What's a Fasted Run?

Fasted running is just that. You run after a long stretch without eating – before breakfast, for example. The result of this is that your body has little to no glycogen reserves (which you build up by eating carbohydrates) to use as energy, so it switches to using your fat reserves.

How long should a fasted run be?

Is It OK to Run In a Fasted State? If you can't stomach eating before a run, it's OK to sometimes go into the session fasted as long as the effort is easy, 60 min or less in duration and you are adequately hydrated.

Is it OK to run fasted?

If you'd rather use your pre-run time in the morning to sleep in a little bit or you can't handle the idea of eating early in the morning, sure, it's OK to do fasted cardio. ... Because of limited glycogen, don't regularly plan long (90 or more minutes) or hard workouts when fasted.