Endure: Mind, Body, and the Curiously Elastic Limits of Human Performance

by Alex Hutchinson

But there were two key differences between the groups. First, pain tolerance increased by 41 percent in the high-intensity group, while the medium-intensity subjects didn’t see any change. This shows that simply getting fitter doesn’t magically increase your pain tolerance. How you get fit matters: you have to suffer. Second, despite the similar fitness gains, the high-intensity group saw much bigger improvements in their racing performance, as measured by a series of time-to-exhaustion tests at different intensities. In one test, the interval group lasted 148 percent longer on the bike, compared to a mere 38 percent gain for the medium-intensity trainers. Intriguingly, the individual improvements in the time-to-exhaustion tests were correlated with the individual gains in pain tolerance, meaning that the cyclists who learned to handle more pain from the tourniquet test were the same ones who managed to cycle faster.