Spend any amount of time with trail and ultra runners these days and you’re likely to hear about the value of training at elevation. Over the course of just a few weeks, your body makes adaptations due to the lower level of oxygen in the air, helping you run faster when you return to sea level. And while most of us don’t have the flexibility to move to Flagstaff, Boulder, or Mammoth to train year-round at altitude, many of us can benefit from short stints up high.
Altitude training isn’t going to turn you into superman overnight. However, even brief stints are likely to show benefits for nearly everyone. While researchers continue to evaluate the exact parameters in which altitude training is most beneficial and where some of the individual variability comes into play, there’s a general consensus on much of the value behind it. Like any training plan, some of this will vary by the athlete and even by the trip you take to elevation.
The science behind training at altitude is, at first, pretty simple. “Thinner” air at higher elevations means less air pressure, and accordingly, lower levels of oxygen available because it is the heavier gas in our atmosphere. At 8,000 feet, oxygen in the air is roughly 75 percentage of what it is at sea level. At 16,000 feet, an elevation few people go to and almost no one trains at, oxygen is just about half what it is at sea level.
Oxygen levels are important because they dictate how hard your body works. For example, at 10,000 feet, most runners spend 30 percent extra energy to run at the same pace at sea level. This extra effort is hard in the moment but is what provides benefits when you return to sea level, increasing the number of red blood cells in the body and increasing the load capacity for your heart and lungs, acting as a surplus when you return to normal altitudes and often lasting a few weeks.
One level deeper, the primary goal of altitude training is an increase in red blood cell volume and total hemoglobin mass, which delivers oxygen to the body. This process is a result of increased erythropoietin (EPO) production by the kidneys upon exposure to altitude, which initiates red blood cell production in the bone marrow. More red blood cells lead to an increase in hemoglobin mass, which is how oxygen is carried around the body. The more oxygen you can deliver to working muscles, the faster you can run. In short, your muscles handle higher intensities like racing conditions better upon descent from altitude.
Magda Boulet, Olympic Marathoner, Western States Endurance Run and Leadville 100 Winner
“The effect of altitude on performance is real. When you arrive at altitude your body goes through some adjustments, heart rate increases, metabolic rate increases, energy expenditure goes up, fluid loss goes up, and there’s increased demand for carbohydrates as fuel. The amount of oxygen that is carried by the hemoglobin in the blood reduces resulting in less oxygen delivered to the exercising muscles, which results in below-normal performance,” said Magda Boulet. “All of these adjustments have a detrimental impact on race performance. Acclimatization takes time, but allowing the body to adapt to some of the demands at altitude has a positive impact.”
The key, Boulet says, is to plan ahead. Prior to arriving at altitude, she suggests heat training adaptations to increase plasma volume and red blood cell count, which results in decreased cardiovascular demand at a given workload, increased blood flow to muscles, better nutrient delivery, and improved thermoregulatory control. “Two to three 30-minute sauna sessions for a few weeks will do wonders!”
She also suggests that you supplement with branch chain amino acids and iron, helping reduce the loss of muscle. Once at altitude, you should adjust your training, starting by letting go of the paces and intensities you normally run and giving yourself two full weeks to build up to it. Take extra time recovering between reps and hard runs, sleep more, hydrate more, and continue to supplement.
Dani Moreno, 2x USA Mountain Running Champ
“The goal of a training block at altitude is to gain from it, not come back deficient and in a physical lull. An altitude plan varies a lot depending on how long the training block is, but if I were to name a few primary things to focus on, it would be: hydration, electrolytes, fuel, and recovery,” said Dani Moreno, who also suggests runners think of altitude training as a way to slow down and build strength, not break their muscles by overtraining. “If you did these things as you would at sea level, you might feel good for a few days or even a few weeks. But the lack of compensation for the extra work you are putting in could catch up quickly and hard if you don’t address them when training at a higher elevation.”
Moreno says that exerting oneself at a high level is never easy, especially with less oxygen. Thus, it’s essential to celebrate the good days and not dwell on the tough outings. When at altitude, it’s necessary to take it easy on yourself and know a hard effort is an arduous effort, regardless of the time you see on your watch. “ In essence, if someone can’t gain altitude’s physical benefits, they can effectively make it up in mental fortitude, drive, and focus.”
Roxanne Vogel, Exercise Physiologist
“Most altitude training camps last at least 2-3 weeks at moderate (6,000-8,000 feet) altitude for benefits to be fully realized upon return to sea level. Major physiological changes occur within the first few days to start the process of acclimatization, but it takes prolonged exposure to solidify those changes so that they persist even after you leave,” said Roxanne Vogel. “It’s worth noting, it seems that our cells may have a sort of “hypoxic memory” built-in that allows for quicker re-acclimatization upon subsequent altitude training. That is, we adjust more quickly the more training camps to altitude we take over the long term. Elite athletes often do multiple altitude training camps per year for this reason.”
Vogel says that time trial performance in elite-level endurance athletes has been reported to increase by ~2 percent from altitude training. That may not sound like much at first, but in reality, it’s often the difference between a gold medal and not making the team at the Olympics. In sub-elite or recreational athletes, there may be an even bigger increase. There is a lot of room for individual responses to altitude training, with some athletes benefiting much more than others. It comes down to the athlete’s unique physiology and how they tolerate hypoxia, or low oxygen availability.
“There is some variance between athletes, but between 7,000-8,000 feet appears to be the optimal training level at which maximal EPO production is stimulated but without the negative effects of ascending to higher altitudes, which can manifest as impaired performance, fatigue, acute mountain sickness (AMS), or high altitude cerebral edema/pulmonary edema, the latter of which can be life-threatening,” says Vogel. Once you get above about 10,000 feet endurance performance sharply declines and the risk of altitude sickness increases dramatically due to the low available oxygen. Consistently training above 8,000 feet is a point of diminishing return if your intent is to perform better at sea level”
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Hayden Hawks, Broken Arrow, Laveredo, Black Canyon, Speedgoat Winner
“Altitude training offers some of the most important performance benefits for endurance sport athletes. If you look at all the top endurance athletes in the world they either live at altitude or do training camp stints at altitude. This is especially true in the ultra and trail running world where most of the races are held at or rise up to altitude at some point in the race, and getting used to that can be very beneficial. Altitude training not only increases performance at a cellular level but also on a physiological level,” said Hayden Hawks. “Just as important as the physical adaptations is the mental component. Training at altitude is hard and that psychological toughness will help you come race day.”
Hawks emphasizes that altitude training needs to be respected. It’s a lot of additional stress on the body and all runners should plan an adjustment phase when they arrive at altitude. The optimal training takes place when you sleep high and train low. Optimal recovery happens at lower elevations where more oxygen is present. He suggests that you avoid going too high in altitude for a long period of time, primarily because it is harder to recover and sleep, which is crucial. “It’s all about finding a balance, just like other parts of training. If done right you’ll be in a good position to see large improvements though.”
Matthew Laye, Professor of Exercise Physiology, USA 100-Mile Champ
“The minimum time to see benefits seems to be 3 weeks. However, there does not seem to be a time limit on when you stop adapting. One recommended strategy is periodization of training camps that occur frequently and are not limited to a single 3-week block,” said Matthew Laye, a professor of exercise physiology at the College of Idaho. “Many elites will do 3-6 trips to altitude each year. These shorter periods are likely sufficient for the non-hematological adaptations.”
Laye says improvement in aerobic capacity can be up to 4 percent in elite runners. The change in a runner’s threshold is less clear, but there does seem to be a documented improvement. He suggests that these benefits can be maximized by monitoring factors such as an athlete’s iron status and system inflammation, starting before runners arrive at altitude. Neglecting these variables is there much of the individual variability on performance outcomes comes into play.
Like others, Laye said training too high results in slowed recovery due to poor sleep, additional stress, and delayed recovery. Too low and you don’t get the red blood cell response that you want. So the sweet spot is about 7,000 – 8,000 feet. And in an ideal world you could get to a lower altitude for fast training.
“Performance is basically how much oxygen you can consume, how efficient you are, and how close to your max oxygen consumption you can maintain for a long period of time. There are both blood related and non-blood related improvements for runners at altitude. The blood improvement is in red blood cell mass which corresponds to how much oxygen you can deliver to muscles, an important component of performance. Non-blood improvements include an increase in running economy potentially through mitochondria being more efficient due to the hypoxic environment.”
After five years and 200,000 miles of #trucklife living in his Toyota Tacoma, Andy now lives in Jackson, Wyoming with his dog Bea. He works as a freelance producer, writer, and photographer and focuses on supply chains, systemic problems, and clever solutions.