Within 10 Minutes of Your Run
If you've been exercising regularly, your muscles and their ATP supply will be ample. Your body will be able to efficiently move oxygen and burn fat and glucose.
But if you're new to exercise, your ATP supply might not be able to keep up with the high demand that running places on your body. You will be fighting the oxygen-producing process. Lactic acid will begin to overwhelm your body, making each minute more cumbersome than the last. Keep pushing.
In this situation, the best thing to do is slow down to a jog. Once you feel OK, then pick up the pace to a run again.
After 30 Minutes on Your Run
Take a bow! It's over. As you slow down and start walking, your energy demand will lessen and you'll begin to breathe normally.
Believe it or not, you may feel pretty accomplished and energized at this moment. That's because your body is producing the mood-elevating hormone called dopamine—the 'feel good' hormone. The increased levels of dopamine may lead to less food cravings—it's a win-win situation.
Sign up for your next race.