Erythropoiesis with endurance training: dynamics and mechanisms

Abstract

The purpose of the present study was to characterize the progression of red blood cell volume (RBCV) expansion and potential volumetric and endocrine regulators of erythropoiesis during endurance training (ET). Nine healthy, untrained volunteers (age = 27 ± 4 yr) underwent supervised ET consisting of 3-4 × 60 min cycle ergometry sessions per week for 8 wk. Plasma volume (PV), RBCV, and overnight fasting hematological markers were determined before and at ,, and of ET. In addition, plasma erythropoietin (EPO), cortisol, copeptin, and proatrial natriuretic peptide concentrations were measured during a 3-h morning period at baseline and postexercise at and PV increased from baseline (2,405 ± 335 ml) at, , and (+374 ± 194, +505 ± 156, and +341 ± 160 ml, respectively, < 0.001). Increases in RBCV from baseline (1,737 ± 442 ml) were manifested at (+109 ± 114 ml, = 0.030) and (+205 ± 109 ml, = 0.001). Overnight fasting plasma EPO concentration increased from baseline (11.3 ± 4.8 mIU/ml) at (+2.5 ± 2.8 mIU·ml, = 0.027) and returned to baseline concentration at and Higher 3-h-postexercise EPO concentration was observed at (11.6 mIU/ml) compared with (8.4 ± 3.9 mIU/ml, = 0.009) and baseline (9.0 ± 4.2 mIU/ml, = 0.019). Linear relationships between EPO concentration and hematocrit (β = -56.2, < 0.001) and cortisol (β = 0.037, < 0.001) were detected throughout the ET intervention. In conclusion, ET leads to mild, transient increases in circulating EPO concentration, concurring with early PV expansion and lowered hematocrit, preceding gradual RBCV enhancement.

Heat acclimation does not affect maximal aerobic power in thermoneutral normoxic or hypoxic conditions

“…The high inter‐individual variability of EPO in our data renders the difference non‐significant. The increases in EPO concentration seem to be initiated by the PV expansion and a lowered haematocrit, which is similar to what happens after 2 weeks of endurance training (Montero et al., ). There are conflicting reports on changes in resting plasma aldosterone concentrations after HA protocols (Kirby & Convertino, ; Nielsen et al., ).…”

Aerobic but not thermoregulatory gains following a 10‐day moderate‐intensity training protocol are fitness level dependent: A cross‐adaptation perspective

“…The finding that only LF individuals demonstrated a higher EPO response by day 6 suggests that the EPO response is potentiated in the untrained versus trained state when humans are subjected to a similar exercise stimulus in terms of duration and relative intensity. Alternatively, an increased EPO response may serve to counteract the concurrent decrease in Hct levels which was stimulated by plasma volume expansion (Montero et al, ). This possibility, however, is not supported by the fact that the MF people expanded their plasma volume with EPO remaining unaffected and no observed correlation between the changes in Hct and EPO (data not shown).…”

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).…”