Hypoxic sleeping tents represent a technological attempt to achieve the benefits of live high/train low while completely eliminating the need to live and train in different locations, as well as the need to live at high altitude. These devices use generators to create a low oxygen environment within a sleep enclosure that simulates the air at high elevations and thus stimulates the same adaptations in blood chemistry. Numerous studies on the effectiveness of hypoxic sleeping tents on blood chemistry and performance have been conducted. Some have shown benefits while others have not. However, “The bulk of the work on the tents shows that they’re largely ineffective in increasing red cell mass unless you can spend an extraordinary amount of time in them,” Chapman says. “To get a significant improvement in red cell mass, you have to be in the tent 16 hours a day or longer.”
A newer and perhaps better technological solution to the live high/train low problem is exactly the opposite of the hypoxic tent solution. Some elite athletes now live and do all of their training at high altitude, but perform some of their quality workouts indoors while breathing from oxygen tanks. This protocol affords athletes the convenience of living and training in one place, the benefits of spending all day every day at high altitude, and the performance advantage of applying their improved blood chemistry to workouts at simulated sea-level (or even sub-sea-level) elevation, thanks to the oxygen tank.
One of the pioneers of this method is Randy Wilber, a sport physiologist at the Olympic Training Center in Colorado Springs, who oversees training with supplemental oxygen with many resident athletes. In a 2000 study involving cyclists living and training at the OTC, the use of supplemental oxygen over a 21-day period of living and training at high altitude resulted in a 15-second average improvement in a high-intensity cycling test, compared to a two-second improvement in controls who trained without supplemental oxygen.
Among the few triathletes who have made use of this method is three-time Olympian Hunter Kemper. He regularly does treadmill interval runs with supplemental oxygen, and believes he derives great benefits from them. Kemper once tweeted, “My legs love running w/ supplemental O2.”
What is 1.5 percent worth?
According to Robert Chapman, a typical competitive triathlete can expect to improve his Olympic-distance triathlon (non-drafting) bike and run splits by the same 1.5 percent margin by which college runners improved through live high/train low in the study mention above. That translates to a gain of 90 seconds or more for the front-running two-hour racer, or the difference between finishing on the podium or out of the money in many races. (Improvements at the iron distance are likely to be smaller because factors other than aerobic capacity play a greater role in limiting performance.)
Yet even with all that’s at stake at the elite level of the sport, very few triathletes are claiming this free advantage. Boulderites continue to waste their time living and training full-time at moderate altitude. Many elite triathletes continue to get less out of live high/train high altitude camps than they could get out of live high/train low alternatives. And still others are wasting their time (by not spending enough time) sleeping in tents. And a great many more aren’t bothering with any of this stuff at all.
How about you? Would you like to race 1.5 percent faster? Then you need to live high and train low, and you need to do it right. Here’s how.
“The keys to doing it right are making sure you pick the right altitude for living, you pick the right altitude for training, you stay there for the right amount of time, which is a minimum of four weeks, and your iron stores are built up strong before you go up and the whole time you’re there,” says Chapman.
What is the right altitude for living? According to Chapman, the sweet spot is between 6,000 and 8,500 feet. (Anything above 9,000 feet produces negative effects, such as compromised recovery, that counteract the blood benefits.) But the ideal spot within that range differs between individuals. Unfortunately, there’s no way to predict if 6,000 feet won’t be quite high enough for you or if 8,500 will be a little too high. “The only way to know is to actually do it and try to objectively get as much data as you can and subjectively see how you feel,” Chapman says.
What’s the right altitude for training? Studies have shown that 4,200 feet is low enough for most athletes, but some “altitude-sensitive” athletes might need to go a little lower. Of course, supplemental oxygen obviates this issue. With it you can and should go all the way down to the equivalent of sea level, or even lower.
Chapman urges all athletes to have their ferritin levels (an indicator of iron status) checked before and while practicing live high/train low. Altitude exposure is not enough to increase the red blood cell count. The body needs iron as a raw material—more iron than your body normally stores. So it’s necessary to take supplemental iron before and after starting a live high/train low training regimen.
Four weeks of live high/train low are enough to stimulate a 1.5 percent performance improvement, and it’s not clear that additional exposure precipitates additional gains. So you don’t necessarily have to relocate to Flagstaff to practice it. You just need to be able to get four weeks off from work. (Good luck with that.)
The biggest unanswered question regarding live high/train low is how close to races it should cease. In the traditional live high/train high model, it’s important to come down from altitude close to race day, but not too close because, on the one hand, you need time to get used to biking and running at sea level, and on the other hand, you start losing those blood adaptations as soon as you leave the mountain.
But with live high/train low it might not matter so much. Because you’re doing your hardest sessions at sea level already, there’s no need to quit altitude exposure before racing for the sake of adapting the neuromuscular system to sea-level intensity. On the other hand, ceasing to live high several weeks before racing is also potentially workable.
“When you come back [down to sea level], you’re effectively blood doped, so all of your sessions at sea level are that much [faster],” says Chapman. “So even as your extra red blood cells go away, your fitness theoretically would increase because you’re able to hammer that much harder.”
Why isn’t everybody doing this?