Chapter 8. Training and Performing at Moderate Altitude Cheung SS. Advanced environmental exercise physiology

Role of red blood cell (erythrocyte) Moderate altitude: 2000-3000 M local arterial hypoxia within the kidneys ↑secretion of erythropoietin (EPO) ↑ RBC production in marrow within the long bones hematopoiesis: ↑ hemoglobin; Polycythemia: ↑ RBC mass autologous blood transfusions (the reinfusion of own blood), ↑ VO2max and exercise tolerance times confirms importance of erythrocyte levels in oxygen-carrying capacity and endurance performance Artificial recombinant EPO (rhEPO).

hematoloical pathway for aerobic improvement from hypoxic exposure exposure

Other factors: ↑economy of movement Andeans have ↑ Hb, but Tibetans have similar Hb to low-landers Low correlation between changes in RBC volume and VO2max ↑economy of movement ↓ submaximal oxygen requirements of 3-10% ↑ Electron transport chain, ↓ H+ leakage through the mitochondrial membrane, ↓uncoupling protein 3 (UCP3) after training

Uncoupling protein

Other factors: ↑muscle buffer capacity hyperventilation, attempt to maintain alveo1ar PO2 levels. ↑ removal of alveolar CO2 respiratory alkalosis (H+ + HCO3 -  H2CO3  H2O + CO2) ↑ muscle buffering capacity from ↑renal excretion of HCO3- (bicarbonate) 2-3 weeks at above 2000 m ↑ muscle buffering in trained individuals

Individual responses variations Many non-responders in live high, train high Insufficient training load? Low association between EPO response to hypoxia and genetic markers linked to the EPO gene or its regulators predicting individual suitability and customization of altitude training remain extremely difficult

Live and training in altitudes live low, train high, has minimal ergogenic effect Suitable for lowland athletes preparing for competitions at altitude Live high, train high, for sea level performance remain equivocal Live high, train low, effective Maximize the physiological adaptation from exposure to hypoxia minimize ↓ exercise capacity at altitude 8-10 hr/day in 2000-2700 m, train at < 1000 m

Hyperoxia training Seems promising Result in higher training tolerance Higher training load Overtraining? Research still equivocal

Practical considerations Short-term (6-24 h) passive exposure at 2100-2500 m required for EPO response In LHTL, 12-16 hr/day in hypoxia At shorter durations, may require higher altitude Decay of altitude adaptations Some <1 week, but some maintained > 3 weeks Periodic hypoxia boost to maintain adaptation? How long is required to adapt for high-altitude competition? 47 hr insufficient Arrive as early as possible, or using hypoxic facility