As Ternay explains, the cool-down allows the body to return to its regular temperature and brings the heart rate back down ... body time to adjust and reduce post-workout soreness.

Something similar happens when you take a break from cardio exercise, which tweaks the heart, lungs, and energy-producing parts of cells called mitochondria, Glatt said. You can “recover more ...

We spoke with a certified run coach and an exercise physiologist who explain how to tell whether it’s your legs or your lungs and heart keeping ... The best way to build up that toughness ...