Altitude Training a Primer
High altitude training is thought to improve performance. The apparent benefits of high-altitude training include: increases in the blood cell stimulating hormone erythropoietin (EPO), which leads to slow increases in red blood cell volume (RBC), and in turn can result in a higher hematocrit level (the proportion of blood that is made up of RBC), allowing the body to maintain higher blood oxygen concentrations during exercise. While this does occur with altitude exposure, the time course for these adaptations, if they do occur, is not short. A commentary by Duke et al. concluded that in order to elicit performance benefits from altitude, one must live at an altitude of 2,000 – 2,500m (~6,500 – 8,200ft), for > 20 hours daily, for a period of no less than 28 days. Meaning that a ‘stint’ to high altitude by going snowboarding for a week is not a sufficient amount of time to elicit the performance gains from altitude exposure. Furthermore, most high-altitude research lacks solid control populations, as well as placebo control, and some studies have incomplete study design leaving many researchers skeptical to the efficacy of altitude training.
The Power of Placebo
It is important to recognize, psychological fortitude/pain tolerance plays a large role in determining the outcomes of endurance performance. The mind’s ability to effect physiologic outcomes is demonstrated through the placebo effect. This is also one of the potential explanations for improvements to altitude training demonstrated by two studies looking at the concept of live high train low, which requires athletes to live at high altitude, but come to lower elevations to train. In the early 1990’s, Stray-Gunderson and Levine, introduced the concept of “Live-High, Train Low” (LHTL) which was first tested in 1997 with 39 collegiate athletes. Briefly, the first six weeks of the study was spent in Dallas, Texas where two weeks were spent normalizing iron levels. The next four weeks were spent doing a LHTL camp. Over four weeks, the 39 runners improved their 5000m time trial performance by 22s (2.1%). The 39 runners were then separated into three groups, 1) Live High Train High, 2) Live High, Train Low, 3) Live Low, Train Low. Each group trained for another 4 weeks. Within 30hrs of returning to sea level the runners participated in another 5000m time trial. The only group that improved their time trial performance was the Live High, Train Low group and they improved their times by another 1.4%. The authors conclude that performance increases were mediated through, increased red cell mass, and the maintenance of oxygen flux during low-altitude training. Numerous other studies have been done and confirmed these benefits across a variety of endurance disciplines. However, none of these studies used a double-blind design to rule out the effects of placebo mediated increases in performance. Siebenmann et al. investigated the effect of LHTL in a double-blind placebo-controlled study in 2012. This study involved 16 trained cyclists who spent 8 weeks at low altitude (<3,600 ft). After this 2-week lead-in period, athletes spent 16 h/day for the following 4 weeks in rooms flushed with either normal air (placebo group) or normobaric hypoxia, corresponding to an altitude of ~9,000 ft. The results showed no difference in hemoglobin mass, maximal oxygen uptake, and mean power output during a 26.15km time trial. This lack of change in performance between the experimental and placebo group highlights the power of placebo, and how the power of the mind could be influencing performance outcomes.
The example above, illustrates some of the issues associated with altitude training, and some of the apparent pitfalls in the methodology of the research itself. This does not mean that altitude training doesn’t have its place in performance benefits. However, if the benefits to high altitude training do truly occur, they are most likely minimal, they take a long time > 28 days, and would require a large investment in time and money.
For most athletes, unless you plan to race at altitude, it’s probably best to invest your money in things proven to help performance, (i.e. sleep, nutrition, strength training, etc.) rather than pursuing altitude training.