Red cell volume response to exercise training: Association with aging

Abstract

Red blood cell volume (RBCV) is a main determinant of cardiorespiratory fitness in healthy individuals. However, it remains controversial to what extent exercise training (ExT) enhances RBCV. Therefore, we sought to systematically review and determine the effect of ExT on RBCV in healthy individuals across all ages. We conducted a systematic search of MEDLINE, Scopus, and Web of Science, since their inceptions until February 2016 for articles assessing the effect of ExT interventions (not including hypoxic training) on blood volumes in healthy individuals. A meta-analysis was performed to determine the mean difference (MD) in RBCV between post- and pre-ExT measurements. Thirty studies were included after systematic review, comprising a total of 299 healthy individuals (mean age = 19-71 years, 271 males). Exercise training programs primarily consisted in lower limb endurance training interventions (mean duration = 15.2 weeks). After data pooling, RBCV was not increased following ExT (MD = 49 mL, 95% CI = -11, 108; P = 0.11). In subgroup analyses, RBCV was increased after ExT in young and middle-aged individuals (mean age <60 year) (n = 106, MD = 81 mL, 95% CI = 0, 162; P < 0.05) but not in older study participants (mean age ≥60 year) (n = 110, MD = 13 mL, 95% CI = -76, 102; P = 0.77). Heterogeneity was not detected among studies in young and middle-aged (I = 0%) and older individuals (I = 0%). In conclusion, RBCV is moderately, yet consistently, enhanced by ExT in young and middle-aged but not in older healthy individuals. Therefore, RBCV adaptations to ExT appear to be age dependent.

Blood volume expansion does not explain the increase in peak oxygen uptake induced by 10 weeks of endurance training

“…The changes in BV reported after 6-8 weeks ET (3-4 sessions week −1 ) typically range from 140 to 550 ml (Bonne et al 2014;Helgerud et al 2007;Montero et al 2017Montero et al , 2015aMontero and Lundby 2017b), whereas a meta-analysis reported a mean increase of 267 ml after ~ 15 weeks of ET (range 1-51 weeks) (Montero and Lundby 2017a). A complex interplay of mechanisms causes the BV expansion in ET that may be affected by the training program, the training status of the subjects and their nutritional status (Montero and Lundby 2018;Sawka et al 2000).…”

Hypovolemia and reduced hemoglobin mass in patients with heart failure and preserved ejection fraction

“…A fundamental principle of cardiovascular physiology refers to the strict dependence of cardiac reserve upon blood volume (BV), which facilitates venous return, ventricular filling, and stroke volume via the Frank–Starling mechanism (Guyton and Hall ; Bonne et al ; Montero et al ). Indeed, BV is a tightly regulated fluid varying as little as 4% over several months in healthy individuals, plausibly owing to its central role in maintaining whole body homeostasis (Montero and Flammer ; Montero and Lundby ). In the presence of a failing heart, acute fluid retention leading to BV expansion is considered a disproportionate compensatory response in the attempt to retrieve cardiac reserve, eventually resulting in clinical congestion (Guyton and Hall ).…”

Cardiovascular response to prescribed detraining among recreational athletes

“…EICR has been thoroughly characterized among elite athletes (2,11,18,19,21,33) and has recently been documented among recreational exercisers who typically perform comparatively lower volumes and intensities of exercise training (1,8,13,28,35). Similarly, the hematologic response to endurance exercise training has been described in novice exercisers where a rapid increase in plasma volume (PV) precedes a slow increase in red blood cell volume (16). A recent meta-analysis concluded that increases in red blood cell volume of 4% can be expected over 15 wk of endurance training in young and middle-aged exercisers (16).…”

“…Similarly, the hematologic response to endurance exercise training has been described in novice exercisers where a rapid increase in plasma volume (PV) precedes a slow increase in red blood cell volume (16). A recent meta-analysis concluded that increases in red blood cell volume of 4% can be expected over 15 wk of endurance training in young and middle-aged exercisers (16).…”