Altitude Training and Endurance Performance (Part 3 of 4)
AEROBIC AND ANAEROBIC PERFORMANCE CHANGE WITH ALTITUDE TRAINING
Acclimatisation to altitude initiates a sequence of musculocardio-respiratory and metabolic adaptations that impact oxygen transport and utilisation. The complementary stimulus of environmental hypoxia can compound the typical physiological adaptations to endurance training and speed-up performance enhancements following return to sea-level. We will discuss the physiological implications of altitude training for both aerobic and anaerobic performance specific to the Live-High-Train-Low (LHTL) method.
1. Aerobic Performance
Endurance performance at sea-level is substantially improved after 4 weeks of “living” at elevated altitude (2500m) and training low (1250m). Research reveals a 3% increase in peak oxygen consumption (VO2max), and a performance increment of 1.1% for elite athletes completing a 3000m run-time time-trial. The effectiveness of the LHTL model was later confirmed (5000m run-time time-trial) with additional positive physiological adaptation found (ventilatory threshold & speed at VO2max). No difference was observed in the control seal-level condition. Furthermore, performance was consistent 1, 2 and 3 weeks following altitude training, demonstrating that adaptation and subsequent performance enhancement can last for up to 3 weeks post-altitude acclimatization. More recently, a study of 5 elite female cyclists performing altitude training (LHTL) reported a significant increase (2.3%) in average power output during a 4 minute cycling time-trial.
Overall, the scientific literature describes that larger increases in endurance performance, coupled with an improvement in running economy and mechanical efficiency are possible with LHTL altitude training in elite athletes, when compared to sea-level training. Moreover, the LHTL-method appears to benefit performance to a greater magnitude in middle distance aerobic events lasting 4–10 minutes (i.e. 4000m team pursuit cycling). It seems the altitude elevation, hypoxic stimulus duration, training load and recovery combined is more influential in driving physiological adaptation than by just completing altitude training exclusively.
2. Anaerobic Performance.
To date, limited research into the effect of altitude training (LHTL) on the anaerobic energy system have been conducted. Early investigation observed a 1% betterment in 400m run-race time following a 10 day acclimatization period at 2200m, while training at sea-level. In contrast, no significant difference was measured in the control group. In addition, the altitude training condition ran substantially faster at a blood-lactate level of 5 mmol/L, when compared to the seal-level group. It is suggested that this enhancement to performance is the result of an increase in skeletal muscle buffering capacity, which was confirmed later by Gore et al.’s study. After 3 weeks of altitude exposure (3000m) and training (600m), endurance athletes demonstrated a significant improvement (18%) in muscle buffer capacity, compared to controls.
In summary, sleeping at moderate altitude (2600-3000m) for 3 weeks or more can lead to practical advantages for athletes. However, the majority of potential benefits may result from peripheral physiological change including buffering capacity or mechanical efficiency, rather than haematological adaptation (increased haemoglobin content & VO2max). It appears the optimal altitude stimulus for increased red blood cell (RBC) production and improved seal-level performance is 4 weeks of exposure at an elevation of 2500m for 20 hours per day. However the absolute minimum hypoxic daily does required for RBC generation is defined as 8-12 hours per day. On the other hand, for non-haematological adaptation, a much shorted altitude stimulus is required.
Millet, G.P., Roels, B., Schmitt, L., Woorons, X. and Richalet, J.P., 2010. Combining hypoxic methods for peak performance. Sports medicine, 40 (1), pp.1-25.