Yes, you can exercise and do intermittent fasting! In fact some athletes prefer doing workouts fasted to optimise their energy levels, build more muscle mass, and to burn more fat. This may take some getting used to though, especially if you usually eat before a workout and if you're workouts are vigorous.
Focus on getting your IF schedule under control, which might mean putting your workouts on hold, doing easier forms of exercise, or changing the times you work out to suit your IF schedule. Gradually work up to your regular workout routine; this shouldn't take more than a few weeks.
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