Hot, humid days are already uncomfortable—now imagine that discomfort multiplied as you go all-out during an evening pickleball game or lunchtime run. For some, that heat can be enough to make you not want to exercise outside at all. But, now is the time to use that workout inspiration we’re all getting from the summer Olympics —because, according to experts, working out in the heat can help us get fitter, if we do it correctly.
Why is exercising in the heat so hard? Higher temperatures and stifling humidity make the body work harder. “I always think that exercise and heat is a big cardiovascular challenge,” says Chris Byrne, registered physiotherapist and senior lecturer at the University of Exeter. That’s because our cardiovascular system has to juggle two substantial jobs: circulating blood, oxygen, and metabolic fuel to our muscles, and cooling our bodies down.
“There’s competing demands. Some of..
.the cardiac output from the heart needs to be channeled into losing heat,” Byrne says. “That can start causing problems.
” That’s when what Byrne calls “heart rate drift” can happen. In cooler conditions, your heart rate will remain steady while maintaining the same effort during exercise. In the heat, despite running at the same speed, for example, heart rate starts to drift up.
“And that is a sign of the cardiovascular system putting more focus on heat loss,” Byrne says. What is heat adaptation? “Our physical fitness in the hot environment can.