2. It takes a long time for your heart rate to slow down
When you’re physically fit and exercising, your heart beats faster to pump needed oxygen throughout your body. Your heart rate can be anywhere between 140 and 190 beats per minute, depending on your age, when you’re considerably exerting yourself. When you stop, your heart rate will decrease by about 20 beats per minute until it’s back at a normal pace, says Livestrong.com. But if you’re out of shape, it could take much longer. The fitter you are, the faster you’ll recover.