Hassane Zouhal
email: hassane.zouhal@univ-rennes2.fr

Fatma Rhibi

Amal Salhi

Ayyappan Jayavel

Anthony C Hackney

Ayoub Saeidi

Karuppasamy Govindasamy

Claire Tourny

Cain C T Clark

; Abderraouf

Ben Abderrahman

Prof Zouhal Hassane

The effects of exercise training on plasma volume variations: A systematic review

Keywords: Hemoglobin, hematocrit, blood volume, red blood cells

The aim of this systematic review was to summarize the evidence on the acute and long-term effects of exercise training on PV, in both trained and untrained individuals and to examine associations between changes in %PVV and change in physical/physiological performance.

Despite the status of participants and the exercise duration or intensity, all the acute studies reported a significant decrease of PV (effect size: 0.85<d<3.45, very large), and ranged between 7% and 19.9%. In untrained individuals, most of studies reported a significant increase of PV in response to different kind of training including endurance training and high intensity interval training (effect size: 0.19<d<3.52, small to very large), and ranged from 6.6% to 16%. However, in trained individuals the results are equivocal. We showed that acute exercise appears to induce a significant decrease of PV in both healthy untrained and trained individuals in response to several exercise modalities. Moreover, there is evidence that long-term exercise training induced a significant increase of PV in healthy untrained individuals. However, it seems that there is no consensus concerning the effect of long-term exercise training on PV in trained individuals.

Introduction

Sports and physical exercise are important elements of lifestyle which are considered beneficial for overall health [START_REF] Skalenius | Performance and cardiac evaluation before and after a 3-week training camp for 400-meter sprinters -An observational, nonrandomized study[END_REF] and there is a large global interest in competitive sports [START_REF] Aagaard | Performance trends and cardiac biomarkers in a 30-km crosscountry race, 1993-2007[END_REF]. Improving aerobic performance is key in many sports as well as being importance in overall health [START_REF] Malm | Physical Activity and Sports-Real Health Benefits: A Review with Insight into the Public Health of Sweden[END_REF].

Aerobic performance depends on many different factors related to physiological parameters,

Accepted manuscript / Final version such as cardiac output (Q) and blood volume (BV) [START_REF] Kanstrup | Acute hypervolemia, cardiac performance, and aerobic power during exercise[END_REF]. It is commonly accepted that Q represents a major limiting factor to high-intensity aerobic performance. The aerobic contribution could reach 30 to 45% during an all-out exercise such as 30s-wingate test and represents a greater proportion during repeated sprint exercise [START_REF] Mcgawley | Oxygen uptake during repeated-sprint exercise[END_REF]. The Q is determined by heart rate, myocardial contractility, and end-diastolic volume, which is influenced by total BV [START_REF] Ahlgrim | Relations between haemoglobin mass, cardiac dimensions and aerobic capacity in endurance trained cyclists[END_REF][START_REF] Pottgiesser | Current strategies of blood doping detection[END_REF][START_REF] De | Blood volume, aerobic power, and endurance performance: potential ergogenic effect of volume loading[END_REF].

In this context, BV and hemoglobin (Hb) concentration play important roles in oxygen transport and aerobic capacity (e.g. maximal oxygen uptake [V ̇O2max]) [START_REF] De | Blood volume, aerobic power, and endurance performance: potential ergogenic effect of volume loading[END_REF][START_REF] Steiner | Does hemoglobin mass increase from age 16 to 21 and 28 in elite endurance athletes?[END_REF]. As such, the oxygen delivery appears to be the main determining factor of performance during aerobic physical exercise [START_REF] Sitkowski | Interrelationships between changes in erythropoietin, plasma volume, haemoglobin concentration, and total haemoglobin mass in endurance athletes[END_REF].

Alterations in [Hb] and red cell volume are known to be linked to changes in blood volume (BV).

Kanstrup et al. [START_REF] Kanstrup | Blood volume and hemoglobin concentra-tion as determinants of maximal aerobic power[END_REF] demonstrated that an increase in endurance performance and VO 2 max occurs when hypervolemia is associated with an elevated [Hb], but not with reduced [Hb]. However, other investigations have showed that VO 2 max can be increased in response to a BV expansion independent of changes in red blood cells (hypervolemic anemia) in untrained individuals [START_REF] De | Blood volume, aerobic power, and endurance performance: potential ergogenic effect of volume loading[END_REF][START_REF] Coyle | Effect of detraining on cardiovascular responses to exercise: role of blood volume[END_REF][START_REF] Coyle | Maximal oxygen uptake rela-tive to plasma volume expansion[END_REF][START_REF] Krip | Effect of alterations in blood volume on cardiac function during maximal exercise[END_REF].

Moreover, in a critical review, Sawka et al. [START_REF] Sawka | Blood volume: importance and adaptations to exercise training, environmental stresses, and trauma/sickness[END_REF] showed that BV changes occur with human adaptations to physical exercise, environmental stresses, and trauma/illness and as such that erythrocyte volume and plasma volume will change independently of each other and make separate contributions to each adaptation [START_REF] Sawka | Blood volume: importance and adaptations to exercise training, environmental stresses, and trauma/sickness[END_REF]. Warburton et al. [START_REF] De | Blood volume, aerobic power, and endurance performance: potential ergogenic effect of volume loading[END_REF] also performed a critical review to determine the potential ergogenic properties of volume loading and concluded that volume loading does not result in an improvement in VO2max and/or endurance performance in endurance athletes. That is, volume loading in untrained individuals may improve VO2max, but does not bring these individuals to the aerobic capacity of endurance-trained athletes.

Within the blood components, plasma and haemoglobin/erythrocytes are the key transporters of nutrients and oxygen to active muscles [START_REF] Sawka | Blood volume: importance and adaptations to exercise training, environmental stresses, and trauma/sickness[END_REF][START_REF] Rhibi | Increase interval training intensity improves plasma volume variations and aerobic performances in response to intermittent exercise[END_REF]; therefore, it is logical that changes in plasma volume (PV) observed after exercise training could affect aerobic performances [8, 15; 17].

Indeed, several studies have demonstrated that induced PV expansion was accompanied by an increase in aerobic exercise performance capacity [START_REF] Warburton | Blood volume expansion and cardiorespiratory function: effects of training modality[END_REF][START_REF] Pavón | High-intensity intermittent training versus moderate-intensity intermittent training: is it a matter of intensity or intermittent efforts[END_REF][START_REF] Zouhal | Influence of training status on plasma volume variations and plasma lactate concentrations in response to supramaximal exercise[END_REF]. PV variations (PVV) depends on several intrinsic and individual factors, such as sex [START_REF] Deschenes | Effects of gender on physiological responses during submaximal exercise and recovery[END_REF], age [START_REF] Berthoin | Plasma lactate and plasma volume recovery in adults and children following high-intensity exercises[END_REF], training level [START_REF] Moussa | Plasma volume variations induced by sprint exercise in sprinters, endurance-trained and untrained male subjects[END_REF], acute exercise duration [START_REF] Altenkirch | Effect of prolonged physical exercise on fluid regulating hormones[END_REF], environmental factors [START_REF] Marieb | Human Anatomy & Physiology[END_REF] and exercise intensity [START_REF] El-Sayed | Vasopressin and plasma volume response to submaximal and maximal exercise in man[END_REF] (figure 1).

However, hematological and biochemical parameters may vary depending on the type, severity, duration of exercises, and feeding status [START_REF] Cinar | Effect of Football Practices on Certain Blood Values of Athletes[END_REF][START_REF] Demiriz | Prevalence and characteristics of supernumerary teeth: A survey on 7348 people[END_REF][START_REF] Pancar | The effect of 4-weekly low intensity physical activity program in thyroid hormone levels in obese and overweight children[END_REF]. The Hb and hematocrit (Hct) values of athletes subjected to intensive exercise programs, characteristically, decrease and this status is regarded as sportsman anemia [START_REF] Londeann | Low heamatcrits during basic training athlete's anemia[END_REF].

Accepted manuscript / Final version

Endurance training necessarily leads to adaptations in the cardiovascular system [START_REF] Hellsten | Cardiovascular Adaptations to Exercise Training[END_REF]; indeed, many studies have demonstrated that endurance training results in increases in Q, increased vascular conductance, and a greater oxygen extraction, with a consequential increase in aerobic power [START_REF] Saltin | The nature of the training response; peripheral and central adaptations of one-legged exercise[END_REF]. The increase in heart rate is responsible for the majority of Q augmentation during exercise; however, maximal heart rate is relatively unaltered with exercise training, with some evidence indicating that heart rate may be reduced during maximal exercise as a chronic training adaptation [START_REF] Zavorsky | Evidence and possible mechanisms of altered maximum heart rate with endurance training and tapering[END_REF].

Many studies have examined the relationship between PVV, BV variations and performances in response to acute and/or chronic exercise [START_REF] Rhibi | Increase interval training intensity improves plasma volume variations and aerobic performances in response to intermittent exercise[END_REF][START_REF] Ben Abderrahman | Running interval training and estimated plasma-volume variation[END_REF][START_REF] Saidi | Effects of a six-week period of congested match play on plasma volume variations, hematological parameters, training workload and physical fitness in elite soccer players[END_REF]. Previous studies have reported that improved endurance performance was accompanied by increases in PV and decreases in Hct [START_REF] Ben Abderrahman | Running interval training and estimated plasma-volume variation[END_REF]. Since physical exercise and training induces changes in PVV levels, it is important to investigate and understand PVV levels in response to acute and log-term exercise training.

Accordingly, we conducted, a systematic review of the effects of acute exercise and long-term exercise training on PVV levels in untrained and trained individuals. Moreover, we examined associations between changes in %PVV and changes in physical/physiological performance.

Methods

This systematic review was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) Statement [START_REF] Moher | Preferred reporting items for systematic reviews and meta-analyses: the PRISMA statement[END_REF]. The PICOS approach (Population, Intervention, Comparator, Outcomes, Study design) was followed to identify inclusion criteria (Table 1). Only randomized controlled trials and controlled trials that examined the acute and chronic effects of training on plasma volume variations (PVV) in trained and healthy untrained individuals were eligible for inclusion. Studies were included in the current systematic review if they were in accordance with the following criteria: [START_REF] Skalenius | Performance and cardiac evaluation before and after a 3-week training camp for 400-meter sprinters -An observational, nonrandomized study[END_REF] published in peer-reviewed journals; [START_REF] Aagaard | Performance trends and cardiac biomarkers in a 30-km crosscountry race, 1993-2007[END_REF] "physiological adaptation" OR "physiological response" OR "heart rate" OR "oxygen uptake" OR VO2 OR "maximal oxygen uptake*" OR "VO2max" OR "aerobic performance" OR "endurance performance" OR "sprint performance" OR "strength performance" OR "cycling performance") AND (plasma OR "plasma volume" OR "plasma volume variations" OR VVP OR blood OR "blood volume" OR "hematological parameters" OR "hematocrit" OR "Hct" OR "hemoglobin" OR "Hgb" OR "Hb")). In addition, the reference lists and citations (Google Scholar) of the identified studies were explored in order to detect further relevant research papers that may have inadvertently been omitted. Since the scope of this review article is large in terms of outcome measures (e.g. performance, physiological adaptations, health indices), a systematic review, but a meta-analysis was not conducted (i.e., the large number of outcome parameters would have yielded high heterogeneity).

In the current review, only studies using a direct or a valid indirect method to estimate PVV were included. For indirect method, changes in whole blood volume (WBV), red cell volume (RCV) and plasma volume (PV) were calculated from the values obtained for haemoglobin concentration and packed cell volume (PCV) before and after acute exercise or long-term training programs, using the calculations described by Dill and Costill [START_REF] Dill | Calculation of percentage changes in volumes of blood, plasma and red cells in dehydration[END_REF]. The equation of Beaumont [START_REF] Beaumont | Disproportional changes in haematocrit, plasma volume and proteins during exercise and bed rest[END_REF] which has been used to calculate changes in PV on the basis of haematocrit values alone is not applicable as it depends upon a constant red cell volume being maintained [START_REF] Maughan | Estimation of plasma volume changes during marathon running[END_REF]. Thus, studies using Beaumont equation only were not included in the present study.

The final screening was performed by two investigators (FR and AJ) based on the relevance

Accepted manuscript / Final version of the inclusion and exclusion criteria and the identified items for assessing the effects of acute and chronic physical exercise on PVV in trained and healthy untrained individuals using PICOS criteria. If the citation showed any potential relevance, it was screened at the abstract level. When abstracts indicated potential inclusion, full-text articles were reviewed.

A third-party consensus meeting was held with a third author (HZ), if the two reviewers were not able to reach agreement on inclusion of an article.

The methodological quality of the included studies was assessed using the Physiotherapy Evidence Database (PEDro) scale (Hcttp://www.pedro.fhs. usyd.edu.au), which has been shown to have good reliability and validity [START_REF] Maher | Reliability of the PEDro scale for rating quality of randomized controlled trials[END_REF]. The PEDro scale has 11 possible points that examine external validity (criterion 1) and internal validity (criteria 2-9) of controlled trials and whether there is sufficient statistical information for interpreting results (criteria 10-11).

A cut-off points of 6 on the PEDro scale was used to indicate high-quality studies, as this has been reported to be sufficient to distinguish high quality vs. low quality in previous studies [START_REF] Maher | Reliability of the PEDro scale for rating quality of randomized controlled trials[END_REF]. Two independent researchers (FR and AJ) assessed the quality of the studies, if any ambiguity arose, a third researcher (HZ) was contacted and a unanimous decision was achieved.

To evaluate the magnitude of the effects, percent change (Δ%) was calculated (if not available in the individual studies) for each study using the following equation: Values for ES were defined as trivial (<0.2), small (0.2-0.6), moderate (0.6-1.2), large (1.2-2.0), and very large >2.0 [START_REF] Londeann | Low heamatcrits during basic training athlete's anemia[END_REF]. Results for each outcome variable are presented with number of observations (N) of Δ% and ES calculated within the review. All data analysis was processed using Sigma Stat 3.5 software (Systat, Inc, USA). Mean percentages of change at different time points extracted from all studies were presented as mean (Range: minimum and maximum) for all parameters. The ES and Δ% were analyzed in studies where sufficient data was available. A significant difference was indicated when the 95% confidence interval Accepted manuscript / Final version (CI) of the ES did not overlap with zero. In addition, the relationships between Δ% of PVV and Δ% of physical/physiological performance were assessed where sufficient data was available using Pearson's product-moment correlation coefficients (r). The magnitude of correlation coefficients were considered as trivial (r < 0.1), small (0.1 < r < 0.3), moderate (0.3 < r < 0.5), large (0.5 < r < 0.7), very large (0.7 < r < 0.9), nearly perfect (0.9 < r <1.0), and perfect (r = 1.0) [START_REF] Cohen | Statistical power analysis for the behavioral sciences[END_REF]. Statistical significance for all analyses was set at p < 0.05.

Results

Overall, our search identified 3349 records (figure 1). After screening of titles, abstracts and full texts, 30 studies were included in our final analysis. Table 2 illustrates characteristics of the 9 acute and 21 long-term studies. The 15 acute studies [16, 19, 21-22, 33, 41-50] were performed in 6 different countries (France, Japan, Canada, Brazil, United States and United Kingdom) and involved 269 participants. Different kinds of exercise activities (walking, cycling and running) with different durations (30s to >1 h) and intensities (maximal and supramaximal) were used.

*Insert table 2 here*

The 25 included long-term studies were classified as 'high-quality' studies (mean 6.7 in the PEDro scale score), and only six studies were classified as 'low-quality' study (mean 3.8 in the PEDro scale score) [1,4 8-49, 51, 52, 53] (Table 3). A total of 474 participants underwent exercise-training programs and completed the studies. The 25 long-term studies were carried out in different countries from five continents (Australia, France, Sweden, United Kingdom, Japan, Poland, Qatar, Switzerland, Denmark, Austria, Tunisia, Iran, Germany and USA). Nine studies investigated both male and female subjects, 15 studies investigated male subjects and 1 study involved only women [START_REF] Branch | Exercise training and intensity does not alter vascular volume responses in women[END_REF]. Fifteen studies investigated healthy trained participants and 10 involved untrained individuals. The training duration was at least 5 to 8 days [START_REF] Convertino | Blood volume: its adaptation to endurance training[END_REF][START_REF] Stephenson | Mixed Active and Passive, Heart Rate-Controlled Heat Acclimation Is Effective for Paralympic and Able-Bodied Triathletes[END_REF][START_REF] Schumacher | Haemoglobin mass in cyclists during stage racing[END_REF],

for several studies it was around between 3 and 8 weeks, for some studies it was around 3 months and for one study the duration was 6 months [START_REF] Derbré | Effets de l'entraînement de sprint et du désentraînement sur les variations du volume plasmatique induites par un test supramaximal chez des adolescents[END_REF].

*Insert table 3 here*

Table 4 summarizes the acute effects of exercise on PVV in trained and untrained individuals.

Five studies [START_REF] Rhibi | Increase interval training intensity improves plasma volume variations and aerobic performances in response to intermittent exercise[END_REF][START_REF] Ben Abderrahman | Running interval training and estimated plasma-volume variation[END_REF][START_REF] Gillen | Plasma volume expansion in humans after a single intense exercise protocol[END_REF][START_REF] Sellami | Hemoglobin, hematocrit and plasma volume variations following combined sprint and strength: Effect of advanced age[END_REF][START_REF] Uchida | Interval Walking Training and Nutritional Intake to Increase Plasma Volume in Elderly[END_REF] were identified that examined the acute effects of exercise on Accepted manuscript / Final version PVV in moderately trained subjects. Two studies [START_REF] Zouhal | Influence of training status on plasma volume variations and plasma lactate concentrations in response to supramaximal exercise[END_REF][START_REF] Moussa | Plasma volume variations induced by sprint exercise in sprinters, endurance-trained and untrained male subjects[END_REF] involved highly trained endurance and sprint athletes. Despite the status of participants and the exercise duration or intensity, all the studies reported significant decrease of PV (effect size: 0.85<d<3.45, very large). The decreases were ranged between 7% [START_REF] Ben Abderrahman | Running interval training and estimated plasma-volume variation[END_REF] and 19.9% [START_REF] Zouhal | Influence of training status on plasma volume variations and plasma lactate concentrations in response to supramaximal exercise[END_REF]. Only one study [START_REF] Pugh | Blood volume changes in outdoor exercise of 8-10 hour duration[END_REF] observed an increase (+7.3%) of PV after 28-mile walk in hill walkers.

*Insert table 4 here*

Ten studies investigated the effect of long-term training on PVV in healthy untrained men and women (Table 5). Most of studies reported significant increase of PV in response to different kind of training including endurance training and HIIT (effect size: 0.19<d<3.52, small to very large). The increase was ranged from 6.6% [START_REF] Kataoka | Effects of hypervolemia by protein and glucose supplementation during aerobic training on thermal and arterial pressure regulations in hypertensive older men[END_REF] to 16% [START_REF] Montero | Erythropoiesis with endurance training: Dynamics and mechanisms[END_REF]. The study of Mtinangi and Hainsworth [START_REF] Mtinangi | Effects of moderate exercise training on plasma volume, baroreceptor sensitivity and orthostatic tolerance in healthy subjects[END_REF] investigated the effect of 3 months of a combination of strength and endurance training in both men and women and reported an increase of 230 mL of PV (effect size: 1.58, very large). However, Green et al. [START_REF] Green | Response of red cell and plasma volume to prolonged training in humans[END_REF] reported 10% increase of PV after 8 weeks of cycling at 62% V ̇O2max (2 h/d) in men (effect size: 2.71, very large). In untrained individuals, there was no significant correlation between change in %PVV and change in physical/physiological performance.

*Insert table 5 here*

Table 6 depicted the 15 studies that investigated the effects of long-term exercise training PVV in trained individuals. Seven studies observed a significant increase of PV (4.6% to 10%; effect size: 0.15<d<1.35, small to large) in moderately or highly trained individuals, men and women in response to endurance training [START_REF] Saidi | Effects of a six-week period of congested match play on plasma volume variations, hematological parameters, training workload and physical fitness in elite soccer players[END_REF][START_REF] Stephenson | Mixed Active and Passive, Heart Rate-Controlled Heat Acclimation Is Effective for Paralympic and Able-Bodied Triathletes[END_REF][START_REF] Bejder | Plasma volume reduction and hematological fluctuations in high-level athletes after an increased training load[END_REF][START_REF] Lobigs | Validation of a blood marker for plasma volume in endurance athletes during a live-high train-low altitude training camp[END_REF], HIIT [START_REF] Rhibi | Increase interval training intensity improves plasma volume variations and aerobic performances in response to intermittent exercise[END_REF][START_REF] Ben Abderrahman | Running interval training and estimated plasma-volume variation[END_REF] and combined training [START_REF] Sellami | Racial differences in hemoglobin and plasma volume variation: Implications for muscle performance and recovery[END_REF].

Three studies observed no significant changes of PV in response to an interval walking training (5 sets at high intensity (>70% V ̇O2peak) and slow at 40% V ̇O2peak) in active men and women [START_REF] Uchida | Interval Walking Training and Nutritional Intake to Increase Plasma Volume in Elderly[END_REF], or to sprint training in untrained men [START_REF] Derbré | Effets de l'entraînement de sprint et du désentraînement sur les variations du volume plasmatique induites par un test supramaximal chez des adolescents[END_REF], or to endurance altitude training (21 nights simulated live high at 3000m) in men and women endurance trained athletes [START_REF] Lobigs | Validation of a blood marker for plasma volume in endurance athletes during a live-high train-low altitude training camp[END_REF], or to HIIT at 90-95 % HRmax in well-trained sport students [START_REF] Menz | Effect of 3-week high-intensity interval training on VO2max, total haemoglobin mass, plasma and blood volume in well-trained athletes[END_REF] (effect size: 0.22<d<2.79, small to large) or to weightlifting in trained men [START_REF] Tayebi | The Effect of Ramadan Fasting and WeigHct-Lifting Training on Plasma Volume, Glucose and Lipids Profile of Male WeigHct-Lifters[END_REF] and to altitude training in men and women world class endurance athletes [START_REF] Heinicke | A three-week Traditional Altitude Training Increases Hemoglobin Mass and Red Cell Volume in Elite Biathlon Athletes[END_REF]. Two studies reported a significant decrease of PV in response to combined training in track and field 400M athletes [START_REF] Skalenius | Performance and cardiac evaluation before and after a 3-week training camp for 400-meter sprinters -An observational, nonrandomized study[END_REF] and in response to 21 days of endurance altitude training camp in international level road cyclists [START_REF] Sitkowski | Interrelationships between changes in erythropoietin, plasma volume, haemoglobin concentration, and total haemoglobin mass in endurance athletes[END_REF] (effect size: 0.84<d<1.00, large).

Accepted manuscript / Final version

In trained individuals, there was no significant correlation between change in %PVV and change in physical/physiological performance.

*Insert table 6 here* Discussion

To the best of our knowledge, the current review is the first systematic review aiming to study the effects of acute exercise and long-term exercise training on plasma volume variations levels in untrained and trained individuals. The results showed that acute exercise appears to induce a significant decrease of PV in both healthy untrained and trained individuals in response to several kind of exercise activities. Moreover, there is evidence that long-term exercise training induces a significant increase of PV in healthy untrained individuals. However, there is no consensus concerning the effect of long-term exercise training on PV in trained individuals.

Recently, only Sawka et al. [START_REF] Sawka | Blood volume: importance and adaptations to exercise training, environmental stresses, and trauma/sickness[END_REF] in their review examined critically the influence of several perturbations (physical exercise, environmental (heat, terrestrial altitude, microgravity, stress, and trauma/sickness) on blood volume. They found that blood volume changes occur with adaptations to physical exercise, environmental stresses, and trauma/illness [START_REF] Sawka | Blood volume: importance and adaptations to exercise training, environmental stresses, and trauma/sickness[END_REF]. More specifically, these authors showed that blood volume increases over time with exercise training and that PV expansion can occur within 24 h and during the first 2 weeks of exposure accounts for nearly all of the blood volume expansion response [START_REF] Sawka | Blood volume: importance and adaptations to exercise training, environmental stresses, and trauma/sickness[END_REF]. However, Sawka et al. [START_REF] Sawka | Blood volume: importance and adaptations to exercise training, environmental stresses, and trauma/sickness[END_REF], the authors did not take into account neither the individual status (trained vs. untrained) nor the duration of exercise (acute exercise vs. long-term exercise training).

Consistent reports on the effect of acute exercise on PVV have been shown, where, despite the status of participants and the exercise duration or intensity, significant decreases of PV are demonstrated [START_REF] Rhibi | Increase interval training intensity improves plasma volume variations and aerobic performances in response to intermittent exercise[END_REF][START_REF] Zouhal | Influence of training status on plasma volume variations and plasma lactate concentrations in response to supramaximal exercise[END_REF][START_REF] Berthoin | Plasma lactate and plasma volume recovery in adults and children following high-intensity exercises[END_REF][START_REF] Moussa | Plasma volume variations induced by sprint exercise in sprinters, endurance-trained and untrained male subjects[END_REF][START_REF] Ben Abderrahman | Running interval training and estimated plasma-volume variation[END_REF][START_REF] Sellami | Racial differences in hemoglobin and plasma volume variation: Implications for muscle performance and recovery[END_REF][START_REF] Sellami | Hemoglobin, hematocrit and plasma volume variations following combined sprint and strength: Effect of advanced age[END_REF][START_REF] Hebestreit | Plasma metabolites, volume and electrolytes following 30-s high-intensity exercise in boys and men[END_REF]. In adult male subjects, Berthoin et al. [START_REF] Berthoin | Plasma lactate and plasma volume recovery in adults and children following high-intensity exercises[END_REF][START_REF] Hebestreit | Plasma metabolites, volume and electrolytes following 30-s high-intensity exercise in boys and men[END_REF] and Zouhal et al. [START_REF] Zouhal | Influence of training status on plasma volume variations and plasma lactate concentrations in response to supramaximal exercise[END_REF] reported a significant reduction in PV from baseline after very strenuous exercise. Several factors such as gender [START_REF] Deschenes | Effects of gender on physiological responses during submaximal exercise and recovery[END_REF], age [START_REF] Berthoin | Plasma lactate and plasma volume recovery in adults and children following high-intensity exercises[END_REF] and the level of training of subjects [START_REF] Moussa | Plasma volume variations induced by sprint exercise in sprinters, endurance-trained and untrained male subjects[END_REF] influence the amplitude of the PVV. For all these factors, it seems that the intensity of exercise plays a major role in this decrease. For example, Berthoin et al. [START_REF] Berthoin | Plasma lactate recovery from maximal exercise with correction for variations in plasma volume[END_REF] reported in adult men a maximum fall of 17.2±3.5% following a supramaximal exercise at 120% of maximal aerobic speed (e.g., velocity eliciting maximal oxygen uptake). These values are slightly higher than those observed in other studies such as that of Hebestreit et al. [START_REF] Hebestreit | Plasma metabolites, volume and electrolytes following 30-s high-intensity exercise in boys and men[END_REF] who found in male physical Accepted manuscript / Final version education and sports students, three minutes after a 30-second Wingate exercise, a 16% drop in PV. However, Zouhal et al. [START_REF] Zouhal | Influence of training status on plasma volume variations and plasma lactate concentrations in response to supramaximal exercise[END_REF] indicated that the level of training also affects the magnitude of the PVV. These last authors measured a maximum fall of -19.97±3.05% in athletes specialized in sprinting, -9.45±3.05% in endurance athletes and -9.05±3.31% in sedentary subjects after a 30 second Wingate. Moreover, Derbré et al. [START_REF] Derbré | Effets de l'entraînement de sprint et du désentraînement sur les variations du volume plasmatique induites par un test supramaximal chez des adolescents[END_REF] measured a maximum fall of -9% in adolescents after a 6-second sprint test carried out on an ergometric bicycle.

Accordingly, the values of PVV did not differ before and after training, and even after detraining.

The aging process impairs balance of fluids and electrolytes [START_REF] Rolls | Aging and Disturbances of Thirst and Fluid Balance[END_REF][START_REF] Phillips | A neural gene from Drosophila melanogaster with homology to vertebrate and invertebrate glutamate decarboxylases[END_REF], leading to reduced PV among elderly individuals [START_REF] Lundvall | Fluid transfer between blood and tissues during exercise[END_REF]. Intensity dependent PV losses have been reported in response to exercise lasting 6 min [START_REF] Wilkerson | Influence of recombinant human erythropoietin treatment on pulmonary O2 uptake kinetics during exercise in humans[END_REF] and 20 min [START_REF] Nevill | The influence of crowd noise and experience upon refereeing decisions in football[END_REF] and changes of similar magnitude have been previously reported following sprinting [START_REF] Rolls | Aging and Disturbances of Thirst and Fluid Balance[END_REF][START_REF] Retallick | Plasma volume response to 30-s cycle ergometry: Influence on lipid and lipoprotein[END_REF][START_REF] Tsampoukos | Effect of menstrual cycle phase on sprinting performance[END_REF][START_REF] Whittlesey | Plasma volume responses to consecutive anaerobic exercise tests[END_REF][START_REF] Stokes | The time course of the human growth hormone response to a 6 s and a 30 s cycle ergometer sprint[END_REF]. Moreover, changes (12.5%) in PV postwarmup were followed by a further 5.5% PV reduction immediately post-sprint, reinforcing the potential influence of intensity of exercise on PV change. Although the literature is sparse with respect to the effect of duration of maximal-intensity exercise on PV change, Stokes et al. [START_REF] Sjøgaard | Extra-and intracellular water spaces in muscles of man at rest and with dynamic exercise[END_REF] reported larger decreases in PV 5 min after a 30-s sprint (14.8%) when compared with a 6-s sprint (5.1%). Finally, 20 min after this exercise (sprinting), PV losses were still evident. The persistence of reductions in PV during recovery from sprinting is probably related to water movements into previously exercised muscles [START_REF] Carter | Muscle pump and central command during recovery from exercise in humans[END_REF] probably due to sustain vasodilation [START_REF] Crisafulli | Hemodynamics during active and passive recovery from a single bout of supramaximal exercise[END_REF][START_REF] Raine | The influence of recovery posture on postexercise hypotension in normotensive men[END_REF][START_REF] Costill | Plasma volume changes following exercise and thermal dehydration[END_REF] and is consistent with other studies adopting similar exercise protocols [START_REF] Retallick | Plasma volume response to 30-s cycle ergometry: Influence on lipid and lipoprotein[END_REF][START_REF] Sjøgaard | Extra-and intracellular water spaces in muscles of man at rest and with dynamic exercise[END_REF].

According to the majority of reports, the hemoconcentration observed after acute exercise is influenced by several factors: 1.) Sweating induced fluid loss, which plays an essential role in moderate-long duration endurance exercise [START_REF] Nielsen | Physical work capacity after dehydration and hyperthermia[END_REF][START_REF] Cohn | Dynamic tensile strength of lunar rock types[END_REF], however, it is likely not implicated in sprinting exercise; 2.) The increase in hydrostatic pressure, secondary to the rise in blood pressure which promotes extravasation of water out of the capillaries [START_REF] Selby | Hematocrit and performance: the effect of endurance training on blood volume[END_REF][START_REF] Van Beaumont | Erythrocyte volume, plasma volume, and acid-base changes in exercise and heat dehydration[END_REF]; 3.) An increase in osmotic pressure, secondary to the accumulation of metabolic by-products (H + ions, lactate, ammonium, K +, etc.) especially following sprint exercise [START_REF] Harrison | Effects of thermal stress and exercise on blood volume in humans[END_REF]; and, 4.) The response of the hormones that control the electrolyte balance including aldosterone (ALD), antidiuretic hormone (ADH) and atrial natriuretic factor (ANF) [START_REF] Harrison | Effects of thermal stress and exercise on blood volume in humans[END_REF].

Jabbour et al. [START_REF] Jabbour | High-intensity interval training improves acute plasma volume responses to exercise that is age dependent[END_REF] showed that after HIIT, the acute PVV decreased were attenuated compared to those observed before HIIT program. Mtinangi and Hainsworth [START_REF] Mtinangi | Effects of moderate exercise training on plasma volume, baroreceptor sensitivity and orthostatic tolerance in healthy subjects[END_REF] showed that PVV increased after 2-3 months of exercise training using the 5BX/XBX Royal Canadian Air Force program. In this context, Jabbour et al. [START_REF] Jabbour | High-intensity interval training improves acute plasma volume responses to exercise that is age dependent[END_REF] showed less change in PV in response to a warm-Accepted manuscript / Final version up after HIIT. Similar results have been reported in response to long-term or relatively shortterm continuous exercise training [START_REF] Convertino | Blood volume: its adaptation to endurance training[END_REF][START_REF] Bejder | Plasma volume reduction and hematological fluctuations in high-level athletes after an increased training load[END_REF][START_REF] Carroll | Effect of training on blood volume and plasma hormone concentrations in the elderly[END_REF][START_REF] Hodges | One session of interval work does not alter VO2max, peak power or plasma volume[END_REF]. Convertino et al. [START_REF] Convertino | Blood volume: its adaptation to endurance training[END_REF] showed that PVV increase by +12% after 8 days of graded training on ergometer cycle at 65% V ̇O2max. Similarly, Carrol et al. [START_REF] Carroll | Effect of training on blood volume and plasma hormone concentrations in the elderly[END_REF] showed that PVV increases by +11% after endurance training for 26 weeks at 40-80% HRmax. Recent studies have shown also significant increase in PVV by 8% after HIIT cycling at 40-50% HR [START_REF] Carter | Muscle pump and central command during recovery from exercise in humans[END_REF], by+16% after endurance training at 50-70% of maximal aerobic velocity (MAV) [START_REF] Montero | Erythropoiesis with endurance training: Dynamics and mechanisms[END_REF] and by +6% after cycling exercise training at 60-75% V ̇O2peak [START_REF] Kataoka | Effects of hypervolemia by protein and glucose supplementation during aerobic training on thermal and arterial pressure regulations in hypertensive older men[END_REF].

Most studies showing PV increases have been conducted in physically fit populations (i.e., athletes, active subjects) and they have evaluated the training effects on PV variations reported a significant increase in PV in response to exercise [START_REF] Carter | Muscle pump and central command during recovery from exercise in humans[END_REF]. According to Mtinangi and Hainsworth [START_REF] Mtinangi | Effects of moderate exercise training on plasma volume, baroreceptor sensitivity and orthostatic tolerance in healthy subjects[END_REF], subjects that had higher initial plasma and blood volumes and (i.e., if the peak recorded oxygen uptake is regarded as a measure of fitness), would also the fittest subjects before starting to train. However, the increase in PV has been proposed as a risk factor that could worsen the symptoms of hypertension by increasing the mean circulatory filling pressure due to decreased total vascular compliance, and increasing venous rerun to the heart/cardiac output, resulting in the renal adaptation and an upward shift of the set point of arterial pressure [START_REF] Mtinangi | Effects of moderate exercise training on plasma volume, baroreceptor sensitivity and orthostatic tolerance in healthy subjects[END_REF].

Silva et al. [START_REF] Silva | Biochemical impact of soccer: an analysis of hormonal, muscle damage, and redox markers during the season[END_REF] showed that PV decreased by 11.2% after 12 weeks of specific soccer training and was significantly correlated to the alteration percentage of Hb and Hct changes. In contrast, Heisterberg et al. [START_REF] Heisterberg | Extensive monitoring through multiple blood samples in professional soccer players[END_REF] recorded no significant changes in Hb and Hct levels over a 6-months period in which the training and match load varied considerably. Indeed, PV measured after a 6-week period of match congestion was significantly higher (+ 6.1%).

Gibala et al. [START_REF] Gibala | Physiological adaptations to low-volume, highintensity interval training in health and disease[END_REF] showed that a short-training period involving high intensity intermittent exercises may result in significant variations of PV. Green et al. [START_REF] Green | Supramaximal exercise after training-induced hypervolemia. I: gas exchange and acid-base balance[END_REF] showed that PV increased by 11.6% in response to three consecutive days of intermittent supramaximal interval cycling exercise in moderately trained subjects. According to data provided by Mtinangi and Hainsworth [START_REF] Mtinangi | Effects of moderate exercise training on plasma volume, baroreceptor sensitivity and orthostatic tolerance in healthy subjects[END_REF], significant increases in PV were reported after 2-3 months of exercise training using the 5BX/XBX Royal Canadian Air Force program. Furthermore, Alis et al. [START_REF] Alis | Microcentrifuge or Automated Hematological Analyzer to Assess Hematocrit in Exercise? Effect on Plasma Volume Loss Calculations[END_REF] reported higher PV loss in response to high intensity training protocol for 10 healthy men compared to aerobic running exercise. It has been shown that high intensity training results in a sufficient decrease in PV to increase plasma constituent concentrations [START_REF] Jabbour | High-intensity interval training improves acute plasma volume responses to exercise that is age dependent[END_REF]. Two main mechanisms may explain the increase in PV with training. The first, of two phases, occur with plasma proteins increases, especially albumin [94]. In fact, when plasma protein concentration increases, the oncotic pressure increases, and fluid is reabsorbed from the interstitial fluid into the blood Accepted manuscript / Final version vessels [START_REF] Convertino | Blood volume: its adaptation to endurance training[END_REF][START_REF] Harrison | Effects of thermal stress and exercise on blood volume in humans[END_REF]94]. Thus, the increase of plasma albumin is responsible of the first phase of rapid PV increase, which occurs after the first hour of recovery from an exercise training session [START_REF] Silva | Biochemical impact of soccer: an analysis of hormonal, muscle damage, and redox markers during the season[END_REF]. During the second phase, protein synthesis is upregulated by repeated exercise exposure, and new plasma proteins are formed. The second mechanism is the secretion of hormones that cause reabsorption of water and sodium in the kidneys, which increases blood plasma, namely antidiuretic hormone and aldosterone [START_REF] Convertino | Blood volume: its adaptation to endurance training[END_REF][START_REF] Harrison | Effects of thermal stress and exercise on blood volume in humans[END_REF]94]. The oncotic pressure exerted by the proteins keep this increased fluid in the vascular space. Nearly all of the increase in blood volume during the first 2 weeks of training can be explained by this increase in plasma volume [START_REF] Convertino | Blood volume: its adaptation to endurance training[END_REF][START_REF] Harrison | Effects of thermal stress and exercise on blood volume in humans[END_REF]94].

It has been demonstrated that the enhancement of aerobic exercise performance is associated with an increase in BV, which consists in a PV increase [START_REF] De | Blood volume, aerobic power, and endurance performance: potential ergogenic effect of volume loading[END_REF][START_REF] Sawka | Blood volume: importance and adaptations to exercise training, environmental stresses, and trauma/sickness[END_REF][START_REF] Convertino | Blood volume: its adaptation to endurance training[END_REF][START_REF] Kargotich | The influence of exercise-induced plasma volume changes on the interpretation of biochemical parameters used for monitoring exercise, training and sport[END_REF][START_REF] Gibala | Short-term sprint interval versus traditional endurance training: similar initial adaptations in human skeletal muscle and exercise performance[END_REF][START_REF] Meyer | Routine blood parameters in elite soccer players[END_REF][START_REF] Hansen | Development of aerobic power in pubescent male soccer players related to hematocrit, hemoglobin and maturation: A longitudinal study[END_REF]. Carroll et al. [START_REF] Carroll | Effect of training on blood volume and plasma hormone concentrations in the elderly[END_REF] showed a significant increase of PVV accompanied by an increase of V ̇O2max (+11.2%) after 26 weeks of endurance training program. Gibala et al. [START_REF] Gibala | Short-term sprint interval versus traditional endurance training: similar initial adaptations in human skeletal muscle and exercise performance[END_REF] showed that 3 to 6 of HIIT sessions for 2 weeks could significantly increase endurance performances.

More recently, Ben Abderrahaman et al. [START_REF] Ben Abderrahman | Running interval training and estimated plasma-volume variation[END_REF] showed a significant increase of V ̇O2max and MAV and a significant correlation after HIIT between PVV and (i) V ̇O2max (r = 0.76) and (ii) MAV (r = 0.60). Kataoka et al. [START_REF] Kataoka | Effects of hypervolemia by protein and glucose supplementation during aerobic training on thermal and arterial pressure regulations in hypertensive older men[END_REF] showed that PVV increased by +6% after cycling exercise training at 60-75% V ̇O2peak accompanied by +13% of improvement in V ̇O2peak performances. In addition, Jabbour et al. [START_REF] Crisafulli | Hemodynamics during active and passive recovery from a single bout of supramaximal exercise[END_REF] showed that PVV increased by +8% after HIIT cycling at 40-50% HR. Montero et al. [START_REF] Montero | Erythropoiesis with endurance training: Dynamics and mechanisms[END_REF] showed that PVV increased by +16% after endurance training at 50-70% MAV accompanied by +11% of MAV performances improvement. Similarly, Rhibi et al. [START_REF] Rhibi | Increase interval training intensity improves plasma volume variations and aerobic performances in response to intermittent exercise[END_REF] showed a significant correlation after HIIT between PVV and TTE. In contrast, several studies conducted with endurance athletes and soccer players showed significant negative correlations between Hct and measures of physical fitness, suggesting increased performance with a decreasing Hct value [START_REF] Hansen | Development of aerobic power in pubescent male soccer players related to hematocrit, hemoglobin and maturation: A longitudinal study[END_REF][START_REF] Burke | Comparison of effect of two interval-training programs on lactate and ventilator thresholds[END_REF]. In fact, changes in PV independent of Hb have more complicated effect on both V ̇O2max and endurance performance due to the concomitant hemodilution effect [START_REF] Rhibi | Increase interval training intensity improves plasma volume variations and aerobic performances in response to intermittent exercise[END_REF][START_REF] Heisterberg | Extensive monitoring through multiple blood samples in professional soccer players[END_REF].

Limitations

The limitation of the current review is that several studies dealing with the effect of a long-term exercise training on PVV used the indirect method (e.g., Dill and Costill method [START_REF] Dill | Calculation of percentage changes in volumes of blood, plasma and red cells in dehydration[END_REF]). The

Conclusion

This systematic literature review demonstrates that acute exercise appears to induce a significant decrease of PV in both healthy untrained and trained individuals in response to several kinds of exercises. Furthermore, there is evidence to suggest that long-term exercise training can also induce a significant increase of PV in healthy untrained individuals. However, there is currently no consensus concerning the effect of long-term exercise training on PV in Adapted version of the recommendations in the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) statement [START_REF] Moher | Preferred reporting items for systematic reviews and meta-analyses: the PRISMA statement[END_REF].

Accepted manuscript / Final version

Long-term studies

• ○ ○ ○ ○ ○ • • ○ ○ • 4
Sitkowski et al. [START_REF] Sitkowski | Interrelationships between changes in erythropoietin, plasma volume, haemoglobin concentration, and total haemoglobin mass in endurance athletes[END_REF] 2018

• ○ ○ • ○ ○ • • ○ • • 6 ○ ○ ○ ○ ○ • • ○ ○ • 4
Bonne et al. [START_REF] Bonne | Phlebotomy eliminates the maximal cardiac output response to six weeks of exercise training[END_REF] 1996

• • ○ • ○ ○ • • ○ • • 6
Schmidt et al. [START_REF] Schmidt | Training induced effects on blood volume, erythrocyte turnover and haemoglobin oxygen binding properties[END_REF] 1988 PV was determined using the Evans blue dye dilution method NC +1.9% (0.5) V ̇O2peak

• ○ ○ • ○ ○ • • ○ • • 6
Stephenson [START_REF] Stephenson | Mixed Active and Passive, Heart Rate-Controlled Heat Acclimation Is Effective for Paralympic and Able-Bodied Triathletes[END_REF] 29/ men, women / 28.0 ± 8.0

Para-triathletes and triathletes

Endurance training: 5 Heart rate-controlled sessions and 3 passive heat exposures PVV (%) = 100× (Hb1/Hb2) × ((1-Ht2×10ˉ²)/(1-Ht1×10ˉ²))-100 ↑ (12.7%; 1.5) +4.5% (0.6) peak power output Derbré et al. [START_REF] Derbré | Effets de l'entraînement de sprint et du désentraînement sur les variations du volume plasmatique induites par un test supramaximal chez des adolescents[END_REF] 12 / men / 14.

  included participants 16 years or older; (3) involved trained and/or untrained individuals; (4) used validated methods of PVV measurements; (5) used exercise testing sessions for cross-sectional studies and, in the case of intervention studies, exercise training programs; and (6) all interventions lasted a minimum of 1 weeks (only for long-term exercise training studies). Studies were excluded if they (1) did not meet the minimum requirements of an experimental study design (e.g. case reports), (2) did not meet the minimum requirements regarding training design (e.g. lack of information on volume, frequency, and/or training methodology), (3) were not written in English, or (4) involved individual with diseases. Moreover, review articles were not included in the current systematic review. Accepted manuscript / Final version *Insert table 1 here* Literature searches were conducted in four electronic databases, including PubMed, ISI Web of Knowledge, Web of Science, and SPORTDiscus, from database inception until December 2020. The following key terms (and synonyms searched for by the MeSH database) were included and combined using the operators "AND", "OR", and "NOT": ((exercise OR "exercise training*" OR "high-intensity interval training*" OR "high-intensity interval exercise*" OR "high-intensity intermittent training*" OR "high-intensity intermittent exercise*" OR "interval aerobic training*" OR "interval aerobic exercise*" OR "aerobic interval training*" OR "aerobic interval exercise*" OR "intermittent aerobic training*" OR "intermittent aerobic exercise*" OR "high-intensity training*" OR "high-intensity exercise*" OR "sprint interval training*" OR "sprint interval exercise*" OR "strength training*" OR "resistance training*" OR cycling) AND ("physical fitness" OR

!

  % = (%&'() -%&+,)/%&+, × 011 Where Mpost represent the mean value after (acute exercise or long-term of training) and Mpre the baseline mean value. Effect sizes (ES) were computed to present standardized effect of acute and long-term training on the outcome variables (e.g. PVV and physical performances). The different ES were calculated using Cohen's d [40] by dividing the raw ES (difference in means) by the pooled standard deviations: 23 = (45678': <) = (=0 -=>)/?@ A55B7<)

  indirect methods available have clear disadvantages when judging PV change because RCV and the number of erythrocytes cannot assumed to be constant. The method described by Dill and Costill can be accurate for acute exercise responses but not for a long-term exercise training effects. In fact, Dill and Costill's description of the RCV-space assumes an unaltered number Accepted manuscript / Final version of erythrocytes in the circulation which can hardly be expected in the long-term exercise training. Thus, this is a clear limitation of the Dill and Costill method. Most certainly more studies using more accurate and precise methods to describe PVV after long-term exercise training are needed.

  trained individuals. Therefore, further studies are needed to investigate the effects of long-term exercise training on PV in highly trained athletes, especially those associated with high intensity endurance training, sprint training, strength training.

  Hb: Hemoglobin; HIIT: High intensity interval training; HIIR: high-intensity interval running; Ht: Hematocrit; MAV: maximal aerobic velocity; BV: blood volume; V ̇O2peak: maximal oxygen uptake; PVV: plasma volume variation; h: hour; d: day; W: week; PV: plasma volume; HRmax: heart rate max; Ht1 = resting Ht (original% Ht); Ht2 = Ht exercise (% final Ht); tHb: Total hemoglobin mass; V ̇O2max: maximal aerobic consumption; TTE: time to exhaustion during intermittent exercise; Ppeak: power peak; NC: no change; SJ: squat jump.

Figure legends:Figure 1 :

 1 Figure legends:

Figure 1 :

 1 Figure 1: Selection process for research articles (n = 21) included in this systematic review.

  Tayebi et al.[START_REF] Tayebi | The Effect of Ramadan Fasting and WeigHct-Lifting Training on Plasma Volume, Glucose and Lipids Profile of Male WeigHct-Lifters[END_REF] 40/ men / NM Trained weight-lifters Weightlifting (1 month with 3 sessions at 90 min per week) PVV (%) = 100× (Hb1/Hb2) × ((1-Ht2×10 ˉ²)/(1-Ht1×10ˉ²))-100 NC NM

Table 2 .

 2 Characteristics of the studies that examined the acute and long-term effects of exercise training on plasma volume in healthy untrained and trained individuals. : velocity; s: maximal aerobic second; MAP: maximal aerobic power; HR: hear rate.

MAV

Table 3 :

 3 Physiotherapy evidence database (PEDro) score of the included acute and long-term studies.

Table 4 :

 4 Effect of acute exercise on plasma volume variation in trained and untrained individuals.

	Hb: Hemoglobin; HIIT: High intensity interval training; Ht: Hematocrit; HRmax: heart rate max; MAV:
	maximal aerobic velocity; PV: plasma volume; PVV: plasma volume variation; Ht1: resting value; Htx :
	value at the time of exercise; d: day; V ̇O2max: maximal aerobic consumption; V ̇O2peak: maximal oxygen uptake;
	W: week.

Table 5 :

 5 Effect of long-term exercise training on plasma volume variation in healthy untrained individuals.

Hb: Hemoglobin; HIIT: High intensity interval training; Ht: Hematocrit; HRmax: heart rate max; MAV: maximal aerobic velocity; PV: plasma volume; PVV: plasma volume variation; Ht1: resting value; Htx : value at the time of exercise; d: day; V ̇O2max: maximal aerobic consumption; V ̇O2peak: maximal oxygen uptake; W: week.

Table 6 :

 6 Effect of long-term exercise training on plasma volume variation in trained individuals.

Table 1 :

 1 Inclusion criteria according to the PICOS approach.

	PICOS components	Details
	Population	Trained and healthy untrained humans
	Intervention	Acute and long-term exercise training
	Comparator	Active and passive controls
	Outcomes	Measures of plasma volume variations (VVP), physical fitness (e.g.
		aerobic performance [VO2max], anaerobic performance),
		physiological responses (e.g., maximal oxygen uptake [VO2max]),
		and hematological parameters (hematocrit, hemoglobin, blood
		volume)
	Study Design	Randomized controlled trials and controlled trials

Table 2 .

 2 Characteristics of the studies that examined the acute and long-term effects of exercise training on plasma volume in healthy untrained and trained individuals.

	Study	PEDro scale	Year	Country	Gender / Status	Sample size	Age, years (mean ± SD or range)	Exercise & Training characteristics	Duration
					Acute studies
	Sellami et al. [43]		2019	France	Men, women / Moderately trained	36	20.8 ± 0.2	Running-based anaerobic running test
	Sellami et al. [44]		2021	France	Men / Moderately trained	28	40.9±2.1	Wingate test, 30s
	Rhibi et al. [16]		2019	France	Men / Moderately trained	39	21.9±1.3	Intermittent exercise
	Uchida et al. [45]		2018	Japan	Men and women /active subjects	27	68.2 ± 1.0	Graded cycling test
	Pereira et al. [46]		2017	Brazil	Men / runners	14	29±4	21.1 km road race
	Tsampoukos et al. [47]		2014	United Kingdom	Women / University sport players	8	23.6 ± 1.8	Maximal 30s sprint
	Ben Abderrahman et al. [33]		2013	France	Men / Moderately trained	15	21.1 ± 1.1	Maximal graded test
	Zouhal et al. [19]		2007	France	Men / Endurance and sprinters highly trained	18	21.2 ± 0.7	Wingate test, 30s
	Moussa et al. [22]		2003	France	Men / Sprinters Endurance highly trained	21	21.1 ± 0.6	Wingate test, 30s
	Berthoin et al. [48]		2000	France	Male	8	Unable to access	maximal exercise and Supra maximal Exercise
	Berthoin et al. [49]		2002	France	Male	16	Unable to access	Incremental and maximal exercise
	Berthoin et al. [21]		2003	France	Male Adult, Children	17	Adult 21.9±1.9 Children 11.3±1.1	maximal exercise and Supra maximal Exercise
	Hebestreit et al. [50]		1996	Canada	Active Boys and adult	10	Adult 24.9±4.9 Children 9.6±0.9	High Intensity Exercise
	Pugh [41]		1996	United Kingdom	hill walkers	6	NM	28-mile walk
								Eight 4-min bouts of exercise at
	Gillen [42]		1985	USA	Active subjects	6	17-23	85% maximal O2 uptake with 5-min recovery periods between
								bouts.

Table 3 : Physiotherapy evidence database (PEDro) score of the included acute and long-term studies.

 3

	4						Training camp (Aerobic
	Skalenius et al. [1]	2019	Sweden	Men / 400 m athletes	23	20.9±2.3	exercises, sprint, jumping,
							strength and agility)

Table 4 :

 4 Effect of acute exercise on plasma volume variation in trained and untrained individuals.

	Study	Population (N/ sex /age)	Status	Acute exercise intervention	Methods of PV measure	Outcomes (% of change)	Effect size (d-Cohen)
	Rhibi et al. [16]	39 /men / 21.9±1.3	Moderately trained	IE at 100% MAV IE at 110% MAV	PVV (%) = 100× ˉ²)/(1-Ht1×10ˉ²))-100 (Hb1/Hb2) × ((1-Ht2×10	↓ (11.6%)	0.7
			Endurance and		PVV (%) = 100×
	Zouhal et al. [19]	18/men/21.2 ± 0.7	sprinters highly	Wingate test	(Hb1/Hb2) × ((1-Ht2×10	↓ (19.9%)	3.5
			trained		ˉ²)/(1-Ht1×10ˉ²))-100
	Berthoin et al. [21]	8 male and 9 prepubertal children	Physical education students and prepubertal children	maximal aerobic power and exercise supramaximal	ˉ²)/(1-Ht1×10ˉ²))-100 PVV (%) = 100× (Hb1/Hb2) × ((1-Ht2×10	↓ (16.9)	1.5
			Sprinters		PVV (%) = 100×
	Moussa et al. [22]	21/ men / 21.1 ± 0.6	Endurance highly	Wingate test	(Hb1/Hb2) × ((1-Ht2×10
			trained		ˉ²)/(1-Ht1×10ˉ²))-100
					PVV (%) = 100×
	Ben / 21.1 ± 1.1	Moderately trained Maximal graded test	(Hb1/Hb2) × ((1-Ht2×10	↓ (7.0%)	0.3
					ˉ²)/(1-Ht1×10ˉ²))-100
	Pugh [41]	6 subjects	Hill walkers	28-mile walk	Determined from blood volume and Ht	↑ (7.3%)	NA
				Eight 4-min bouts of
				exercise at 85%
	Gillen [42]	6 men (17-23)	Active subjects	maximal oxygen uptake with 5-min	PV was determined using the Evans blue dye dilution	↓ (15.0%)	NA
				recovery periods
				between bouts.
	Sellami et al. [43]	28 / men / 21.2±1.2 / 40.9±2.1	Moderately trained Wingate test	PVV (%) = 100× ˉ²)/(1-Ht1×10ˉ²))-100 (Hb1/Hb2) × ((1-Ht2×10	↓ (12.7%)	0.8
				Running-based
	Sellami et al. [44]	36 / men, women / 20.8±0.2	Moderately trained	anaerobic running with 10 s of recovery test; six 35-m sprints	PVV (%) = 100× ˉ²)/(1-Ht1×10ˉ²))-100 (Hb1/Hb2) × ((1-Ht2×10	↓ (12.6%)	1.3
				in-between.

MAV: maximal aerobic velocity; PVV: plasma volume variation; Ht1: resting value; Htx: value at the time of exercise; W: week, ↓: decrease.; ↑: increase; NA: not available.

Table 5 :

 5 Effect of long-term exercise training on plasma volume variation in healthy untrained individuals.

	Study	Population (N/ sex /age)	Training intervention	Methods of PV measure	PVV (% of changes; d-Cohen)	Physical performances and physiological outcomes (%changes; d-Cohen)
	Kataoka et al. [58]	21 / men, women /69.0±1.0	Cycling exercise training: 3 sessions per week. Session of 60 min at 60 -75% of VO2peak	PV was determined using the Evans blue dye dilution method	↑ (6.6 %; 0.9)	+12.8% (2.2) V ̇O2peak
	Montero et al. [59]	9 / men, women / 27.0±4.0	Endurance training at 50 to 70 % MAV	PVV (%) = 100 × [(Hb1/Hbx) × (100 -Htx)/(100 -Ht1)] -1.	↑ (16%; 0.3)	+11.4 % (0.4) V ̇O2max
	Mtinangi and Hainsworth [60]	11 / men, women / 40.0 ±0.1	Strength and endurance training	PV was determined using the Evans blue dye dilution	↑ (230 ml; 1.6)	Data unavailable
				Red cell mass measured by Cr-labeled
	Green et al. [61]	8 / men / 21.3 ± 1.4	Cycling 62% VO2max (2 h/d)	RBC and PV by 1-labeled human	↑ (10%; 2.7)	+17.2% (1.9) V ̇O2max
				serum albumin
					↑ (6 %) cycle
	Branch et al. [54]	26 / women / 32 ± 5	Treadmill training or cycle training 3-5 times / W at 80% VO2max during 12 W	PV was determined using the Evans blue dye dilution	training training ↓ (5 %) treadmill	NM
	Jabbour et al. [86]	30 / men, women /38.0 ±3.0	HIIT cycling at 40-50% HRmax	PVV (%) = 100× (Hb1/Hb2) × ((1-Ht2×10 ˉ²)/(1-Ht1×10ˉ²))-100	↑ (8.4%; 0.2)	NM
			Endurance training (uphill treadmill
	Carroll et al. [87]	38 / men, women/ 67.5±5.2	walking) for 26 weeks: 1W-4W: 40-50% HRmax 5W-W14: 60-70% HRmax	PV was determined using the Evans blue dye dilution	↑ (+11.2%; 3.5)	+11.2% (0.5) V ̇O2max
			>15W: 75-80% HRmax
	Convertino et al. [53]	4 / men / 22.0 ± 2.0	Graduate training on ergometer cycle at 65% VO2max (2h/d)	PVV (%) = 100× (Hb1/Hb2) × ((1-Ht2×10 ˉ²)/(1-Ht1×10ˉ²))-100	↑ (12.3%; 0.3)	+11.2% (1.9) V ̇O2max
	Bonne et al. [100]	9 / men / 27 ± 3	60 min; 4 times weekly at 65% VO2max for 6 W	PVV (%) = 100× (Hb1/Hb2) × ((1-Ht2×10 ˉ²)/(1-Ht1×10ˉ²))-100	↑147 ± 168 ml (5 ± 5%)	+10 ± 7% V ̇O2max
	Schmidt et al. [101] 6 / men / 23.6 ± 2.3	Three weeks ergometer training 5 times a week for 45 min	PV was determined using the Evans blue dye dilution	↑ (13%; 0.9)	+10% (1.1) V ̇O2max

Table 6 :

 6 Effect of long-term exercise training on plasma volume variation in trained individuals.

							Physical
	Study	Population (N/ sex /age)	Status	Training intervention	Methods of PV measure	PVV (% of changes; d-Cohen)	performances and physiological outcomes (%changes; d-
							Cohen)
	Skalenius et al. [1]	23/men/20.9±2.3	400 m athletes	Aerobic exercises, speed endurance, short sprint, jumping, strength, core and agility exercises	PVV (%) = 100× (Hb1/Hb2) × ((1-Ht2×10ˉ²)/(1-Ht1×10ˉ²))-100	↓ (4.5 %; 1.0)	-2.0% (0.6) 300m sprint test
	Sitkowski et al. [10]	32 / men, women / 20.3±2.6	International level road cyclists	21 days of endurance altitude training camp	PV were determined by optimized carbon monoxide (CO) re-breathing method	↓ (0.3 L; 0.8)	NM
	Rhibi et al. [16]	39 / men / 21.9±1.3	Moderately trained	HIIT at 100% MAV and 110% MAV)	PVV (%) = 100× (Hb1/Hb2) × ((1-Ht2×10ˉ²)/(1-Ht1×10ˉ²))-100	↑ (8.0%; 0.7) +32.5% (2.0) TTE
	Ben Abderrahman et al. [33]	15 / men / 21.1±1.1	Moderately trained	HIIT at 100% -110% MAV	PVV (%) = 100× (Hb1/Hb2) × ((1-Ht2×10 ˉ²)/(1-Ht1×10ˉ²))-100	↑ (5%; 0.3)	+6.8% (0.4) V ̇O2max
	Saidi et al. [34]	18 / men /20.1 ± 0.4	Soccer players	Low/moderate intensity continuous running at 50-70% HRmax HIIR at 90-100% HRmax)	PVV (%) = 100× (Hb1/Hb2) × ((1-Ht2×10ˉ²)/(1-Ht1×10ˉ²))-100	↑ (6.1%; 0.6) +2.5% (0.5) SJ
				Combined sprint and resistance training
	Sellami et al. [43]	28/ men/ 21.2±1.2 / 40.9±2.1	Moderately trained	(sprint cycling at 100% PMA, sprint running at 50%VMA and resistance exercise at 40-	PVV (%) = 100× (Hb1/Hb2) × ((1-Ht2×10ˉ²)/(1-Ht1×10ˉ²))-100	↑ (4.6%; 0.7)	+10.9% (1.1) V ̇O2max
				65% 1-RM)
	Uchida et al. [45]	27 / men, women / 68.2±1.0	Moderately trained	Interval walking training (5 sets at high intensity (>70% V˙O2peak) and slow at 40% V˙O2peak)

No funding was received for the conduct of this review and/or preparation of this manuscript.

Data sharing not applicable to this article. All data extracted are presented in tables.

Abbreviations:

HR: hear rate; MAV: maximal aerobic velocity; MAP: maximal aerobic power; s: second; NM: not measured. Scumacher et al. [