Living and training at altitude has a number of beneficial effects for endurance athletes. Many high-level endurance athletes, across many different sports, live at altitude full-time, or use periods of altitude training to enhance their performance.
At the 2017 NCAA Cross Country Championships, in Divisions I and II, both the Men’s and Women’s team champions were from schools located at altitude. In Division I on the men’s side, Northern Arizona University, located in Flagstaff at 6,910 feet above sea level, won its second team title. On the women’s side, the University of New Mexico, located in Albuquerque at 5,312 feet, also won its second team title. In Division II, Adams State University, located in Alamosa, Colorado at 7,544 feet, won both the men’s and women’s team races for its 44th and 45th cross country team titles.
Additionally, a survey of medalists from the 2004 Athens Olympics found that 80% utilized altitude training in some form during their preparations.
The difficult questions, when using periods of altitude training rather than living at altitude, are when to go, for how long, and what to do while there in order to make the most of it. Before we can answer these questions, we need to look at the physiological adaptations to altitude to understand why it is beneficial.
How Much Does Altitude Improve Performance?
Altitude training increases aerobic ability by increasing the volume of red blood cells in the body, as well as the density of mitochondria and capillaries. The result is the ability to run faster for the same distance, or further at the same pace, improving endurance performance.According to the USATF, 4 weeks at altitude can improve performance by 1-2%, and even up to 5%. Click To Tweet
According to the USATF, a 28-day stint at altitude can improve performance by 1-2%, and some athletes have improved up to 5%. That doesn’t sound like much, but for a 31:00 10K runner, that is an improvement of 18-37 seconds, and up to 93 seconds.
Physiological Adaptations to Altitude
Living at altitude results in an increase in naturally occurring erythropoietin. Erythropoietin, abbreviated as EPO, is a hormone produced in the kidneys that stimulates the production of red blood cells. Artificial EPO—synthetic or taken from human or animal sources—was originally developed for cancer patients to increase their red blood cell count, but it has become notorious for its use as a performance-enhancing drug, to exceed the levels naturally and safely produced by the body.
This increased red blood cell production depends on the altitude at which you live, and for how long you live there. Higher altitudes and longer residences result in the production of greater amounts of red blood cells.
In addition to greater oxygen availability as a result of more red blood cells, the efficiency of oxygen use also increases, as a result of the increase in bisphosphoglyceric acid, or BPG. BPG stabilizes deoxygenated red blood cells, allowing for greater oxygen removal from the cells to the working muscles.
Training at Altitude Variations
In order to maximize the effects of altitude, there are different ways an athlete can choose to live and train in a high-altitude environment.
Live High Train Low
Live high train low (LHTL) gives the benefits of altitude without as many of the negatives. The athlete still gains the physiological effects of living at altitude, while maintaining the ability to run sea level paces or sea level workouts. This is only possible in a few locations in the U.S., where there is easy access to both high and low altitudes within a short travel distance.
You can also simulate this type of training at sea level with the use of expensive altitude tents or altitude chambers. Altitude tents simulate the effects of altitude by increasing the percentage of nitrogen in the air, which decreases the percentage of oxygen.
Most altitude training, especially when athletes do short periods of it, will be live high train high (LHTH).
Live High Train High
When training at altitude, it is not always easy to travel to sea level or even lower altitudes. In these circumstances, living and training at the same or similar altitudes are employed. This format allows for the physiological changes to occur, but does require some adjustments to be made to training to accommodate the demands of altitude.
Adjusting Your Training
The reduced availability of oxygen essentially results in a reduced ability to run, as well as a reduced ability to recover from hard efforts, especially before adaptations have occurred.
Running slower, especially on easy days, is necessary to allow for proper recovery. This is because not only does living at altitude affect the acute ability to perform work, but the chronic effect slows down the recovery process.At altitude, run for the same number of minutes a typical run for mileage would take at sea level. Click To Tweet
Running for minutes, rather than miles, will result in the effect of running at sea level, without the psychological pressure to hit a certain mileage goal. Running for the same number of minutes a typical run for mileage would take at sea level is a good goal to shoot for. For example, instead of running for 10 miles at a 6:30 pace, at altitude you should just run for 65 minutes.
This same principle can be applied to tempo runs—running at a given effort for the same amount of time rather than a particular distance. This requires some discipline, because it is tempting to run too fast, in an attempt to run sea level pace or what you think altitude pace should be, especially when wearing a GPS watch. However, just like at sea level, when you run your tempo runs too fast, too much lactate is produced and the purpose of the workout is lost.
When performing interval workouts, you can modify them in three different ways for a given workout. If that given workout would be 6×1600 @ 5:00 with 2:30 rest at sea level, here are three examples to modify that.
- The first, and simplest, modification would be to perform the same distance, with the same rest, but at a slower pace to accommodate the altitude. Given an altitude of 7,500 feet, this would result in a workout of 6×1600 @ 5:18 with 2:30 rest. The problem with this workout is that when you go back to sea level and try to race at a 5:00 pace, it will feel challenging neuromuscularly. You will not be efficient at that pace because you have not run it, despite being aerobically fit from the altitude training. This type of modification is good, but it should also be matched with workouts that will neuromuscularly prepare you for the pace of sea level racing.
- The second strategy, to accommodate sea level pace, would be to increase the recovery between the intervals, in order to run them at the same pace. This would result in a workout of 6×1600 @ 5:00 with perhaps 3:00 or 3:30 rest. However, this begins to change the physiological effect of the workout, as the rests become very long between intervals, and the pace is faster than a 10K effort, at the current altitude.
- Finally, you can break the intervals into shorter bouts to increase total rest so that you can run faster paces. A possible permutation of this workout would be 6x4x400 @ 75 with 60 seconds’ rest between reps, and the original 2:30 rest between sets. This modification approximates the results of a sea level workout, allows for sea level paces to be run, and keeps the recovery short enough to continually stimulate the proper energy system. The repetitions are also short enough that the altitude will not affect you as much as it would in longer repetitions.
When you train at altitude, there are a few other things you should know about to stay as healthy as possible.When you live/train at altitude, take iron supplements, get more sleep, hydrate & dress in layers. Click To Tweet
Athletes training at altitude should take iron supplements, as iron is a necessary component of red blood cell production. There are two different types of supplemental iron that can be taken: liquid and pill form. The liquid form is superior because it has a much higher absorption rate, relatively, than pill form. However, it is also more likely to upset your stomach. The recommendation would be to try the liquid form, and if you can’t handle it, take the pill form instead.
Many manufacturers recommend that their iron supplements be taken with food. This will reduce the likelihood of stomach upset, but will also severely impede absorption. To maximize the already low absorption rates, do not take iron within an hour before or after eating, and only pair it with a high vitamin C liquid. Avoid calcium in this period, because it especially impedes iron absorption.
Take iron for a few weeks before the start of altitude training, to build up the ferratin stores that are used when creating new red blood cells. If ferratin stores are too low to create new red blood cells, spending a few weeks at altitude will not have the hoped-for beneficial effects.
While living and training at altitude, it is important to get more sleep, for two reasons. The first is that sleep quality can be worse while at altitude, so spending more time in bed to get the same number of REM cycles and quality becomes necessary. The second is that altitude is an additional stressor on the body, which requires extra recovery.
Most altitude locations have very low humidity. When this is combined with the higher respiration rate at altitude, there is a greater loss of water through expiration and sweating. In order to replace this, it is necessary to drink extra water frequently, and in larger volumes than usual, the whole time you are at altitude.
Because of the elevation, temperature changes are much greater at higher elevations, compared to lower elevations. Keep this in mind when you plan to spend more than a few hours outside. If you are planning on increasing elevation, be prepared for a decrease of anywhere from 3-6 degrees Fahrenheit, depending on conditions, per 1,000 feet of elevation gain. Dress in layers that you can add or remove as necessary.
Altitude sickness is a reaction to increasing altitude too quickly. It usually occurs above 10,000 feet; however, it can occur at any point. The symptoms include a headache, nausea, loss of appetite, shortness of breath, fast heart rate, and fatigue. The only remedy is to reduce your elevation, or take supplemental oxygen. You can preempt altitude sickness by taking iron ahead of time, hydrating properly and adequately, and increasing your altitude a little at a time.
How High to Live
For short stints at altitude, the best elevation seems to be between 7,000 and 8,000 feet. One study suggested that, during a short stint, only athletes that lived and trained in this range had measurable increases in Vo2 max, as well as improvements in 3,000-meter race performances.The comfort of a lower elevation may balance out the larger emotional stress of a higher altitude. Click To Tweet
Any elevation above 3,000 feet is considered altitude, with increasing physiological response as altitude increases, up to about 9,000 or 10,000 feet. The comfort and convenience of a lower elevation might also balance out the extra physiological effects but increased emotional stress of a higher altitude location. Especially with your first trip to altitude, making it an easy and comfortable experience outweighs trying to get as high as possible, or trying for some optimal altitude.
The Optimal Length of Stay at Altitude
There is a clear increase in red blood cells after just one week at altitude, but the increases are exponential for each additional week. This is especially true in the three- to four-week range.A stay of 3-4 weeks will result in the best ratio of red blood cell production to time at altitude. Click To Tweet
Any time spent at altitude will result in some improvement in red blood cell production, but a stay of three to four weeks will result in the best ratio of red blood cell production, compared to time spent at altitude.
Chapman, Robert & Wilber, Randy. “Altitude Training for Sea Level Performance: Best Practices and Timing for Championships.” Handout for 2011 IAAF Athletic Championships, Daegu, South Korea.