It was pretty cool to get a glimpse into the details of Kilian Jornet’s Everest acclimatization plan (as I described in an article last month)—the altitude tent, the treadmill workouts with an altitude mask, the bonus week in the Alps before heading to the Himalayas, and so on. But let’s be honest: most of us have neither the time nor the resources to implement a plan like that before our own mountain adventures. The benefits of reading about it are mostly vicarious.
So let’s consider, instead, a humbler approach that’s less convincingly researched but more accessible. Or rather, reconsider it. Back in 2015, I wrote about the idea of training your breathing muscles to improve endurance performance at altitude. At the time, it was an intriguing idea backed by very patchy evidence, but a pair of new studies bolster the case.
When you head to altitude, you have to breathe more deeply and more frequently to compensate for the scarcity of oxygen in the thin air. That means the muscles you use to inhale have to work way harder than normal—in fact, those muscles consume 15 to 30 percent of the total oxygen you inhale at altitude. And they eventually get tired. So training those muscles, using a special device allows you to vary the resistance as you inhale, should prepare you to handle the extra work of breathing at altitude. In January, a research team headed by Jesús Álvarez-Herms of the University of Barcelona published a review of studies linking respiratory muscle training to endurance performance at altitude in Frontiers of Physiology.
They found seven relevant studies, and concluded that a month or two of respiratory muscle training did indeed allow the breathing muscles to fend off fatigue for longer, kept oxygen levels in the blood higher, and increased the amount of blood flowing to the muscles used for running or cycling. Of course, what we’re really interested in is whether it makes you faster or able to perform better. The data on that was mixed, but another new study, this one in the International Journal of Sports Physiology and Performance, adds some encouraging findings. A group at Indiana University led by Robert Chapman put 14 endurance-trained volunteers through a pair of 20K cycling time trials at a simulated elevation of 7,000 feet, separated by six weeks of either real or sham respiratory muscle training—and it worked.
Once again, there was a significant difference in the physiological measurements. Here, for example, is the amount of air the subjects were inhaling (in liters per minute) during their time trials, at 4K intervals. The real training group is on the left, and the sham training group is on the right; the black circles show the baseline time trial, and the white squares are the post-training time trial.