High-intensity interval training is great for you—but it won't keep you from aging

Exercise is hard. That should go without saying, but it's worth acknowledging. It's difficult enough to instill a new habit without all the things that make exercise uniquely unpleasant at first. You generally have to go to a crowded place full of cranky strangers, share equipment in close quarters, and sweat and shower alongside them. But on top of that, oh yeah, it's hard. A lot of the movements are weird and awkward for newcomers. Maybe you have to stick your butt up in the air, or wiggle aro