If you’re a runner, you might not realize that your period can affect how you train. Progesterone, which is highest around days 20-22 of a 28-day cycle, increases water retention and body temperature, so running outside on a hot day at that time of the month isn’t the best idea.

Estrogen, on the other hand, helps us break down fat, delaying that “hitting the wall” sensation and helping us burn more calories. Estrogen levels are highest on about days 14-15 of a 28-day cycle, so this is a great time for a long run.

Being attuned to your body’s fluctuations can go a long way!

READ MORE: What to Eat During Your Period