You have probably heard of elite athletes spending stints in thin mountain air at strategic times during the year to enhance their training. What is the purpose of this? Does it actually help? Let's dive into the specifics of altitude training.
Altitude training is when athletes go to higher altitudes than that they typically compete at in an effort to enhance their fitness. The intention is to boost their fitness by training in a less oxygen rich environment. The exact mechanism responsible for the improved training effect is not widely agreed upon in the research. However, it is accepted that when executed correctly, this training stimulus does have an effect on a large percentage of individuals.
The author and coach Steve Magness describes altitude as a “stressor”. Just like you would run an interval workout, lift weights, or go on a long run to put a “stress” to your body, the intention is for your body to adapt in response to a stressor, thus enhancing your fitness. Altitude training is one of many ways to introduce stress to the body with the intention of stimulating adaptation, and ultimately, enhancing athletic performance.
How Does It Work?
Just as the exact mechanism (or more likely multiple mechanisms) that cause fatigue in the body when exercising are not universally agreed upon, so are the mechanisms behind altitude induced adaptations. Some of the proposed theories behind the fitness boost include improved exercise economy, improved hemodynamic function, and changes in metabolic function.
Exercise economy, which is often expressed as VO2, pertains to how efficiently your body uses oxygen during exercise. The effect of living and exercising in a less oxygenated environment, such as on a mountain, will over time result in the adaptation of your body to require less oxygen at a given speed. Essentially, your body becomes more efficient at using less oxygen at a given running speed.
Hematologic changes refer to the impact on your blood at a cellular level. It is postulated that training at altitude enhances red blood cell production. Having more red blood cells means your body is more readily able to transport oxygen to your tissues, increasing time to fatigue.
It has also been proposed to positively impact your muscles’ “buffer” capacity, or their ability to neutralize the higher pH (acidity) that accumulates as a result of exercise. This means the accumulation of bi products in your blood will not produce fatigue as quickly while running fast.
Some sources conclude that the fitness adaptation is the result of metabolic changes, where your body shifts more heavily towards glucose metabolism. Glucose is a more efficient energy source in terms of oxygen consumption, so this may play a role in the increased exercise efficiency.
How Long Does It Take?
Studies vary widely regarding the ideal parameters for altitude training. This is not surprising, as there is going to be a variation in how different individuals respond to a stimulus, and not all variables can be easily controlled.
One study looked at the response of adolescents aged 14 - 18 with at least two years of structured running experience. Amongst this group, the majority of runners reaped benefits from an 11 day stint at 6,000 feet. This was similar to the results of a study on college-aged students who completed a 10 day camp.
However, other studies have looked at a longer duration period of high altitude exposure in the range of 20 to 30 days. The USATF Distance Initiative Report published in 2015 recommends 28 days or more at altitude to see the benefits, and, at minimum, 21 days. Their rationale for this longer duration is based on the mechanism of red blood cell production driving adaptation, since it takes 15 to 18 days for red blood cell development and turnover.
How High?
There appears to be an ideal altitude “window” that impacts performance, between 6,000 and 8,000 feet. Research on groups of individuals living and training at moderate altitudes lower than 6,000 feet, did not show the same training boost as those studied living at higher altitudes.
Live High, Train Low.
Living and training at higher altitude may not be the ideal model. Several researchers have concluded that living high and training low has a stronger training effect than living and training at high or moderate altitude. Living and sleeping at higher altitude and then going down to lower altitude to perform higher intensity longer interval workouts greater than 300 m has been found to be most effective. Essentially, training at lower altitude allows the athlete to perform higher intensity, faster training than they would be able to in a less oxygen rich environment. Yet, the majority of the time they are living in a less oxygenated environment that will in theory drive adaptation, when compared to controls living low and training low.
Monitor Your Response.
If you want to maximize your response to the stimulus of altitude, it is recommended that you monitor your response, via blood testing, both before and after altitude. Since red blood cell production is a key component of this type of adaptation, if your body’s ability to transport oxygen is compromised before you add in this stimulus, via low iron levels, it will likely prevent you from optimizing the benefits. Thus, making sure you are in a good spot to embrace this type of training, while also monitoring your response afterwards, can be useful.
Training ‘Camp’
From a personal perspective, I have found attending an altitude ‘camp’ to be a beneficial stimulus. For the first few weeks running and living at altitude, I usually feel very fatigued and out of breath when running intervals, even when I travel down to lower altitudes to do so. However, I also find that traveling to higher altitude allows me to buckle down and focus on my training with fewer distractions. It also usually means surrounding myself with talented runners to train with and to help with motivation. For me, this psychological boost may be just as beneficial, if not more so, than the stimulus of high altitude itself.
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