Can workouts affect your period?

Exercise can have subtle or extreme influences on your menstrual cycle, depending on how your body reacts to physical activity. 

It makes sense that menstruation and fitness are connected - your period is controlled by your body’s production and regulation of hormones, while the physical demands of exercise affect those hormone levels. 

It can impact your body in several ways...

Exercise can lighten your flow

Hormonal changes from a regular fitness routine can make your periods less heavy. One reason for this is down to oestrogen and weight loss.

The more body fat you have, the more oestrogen is produced from the fat tissue. This excess hormone can thicken the lining of your uterus, so more blood builds up in the first half of your cycle. 

When you lose weight through exercise, you have less oestrogen in your body. As a result, your lining gets thinner, and your flow gets lighter.

Workouts can make cramps less painful

You may not have heard of prostaglandins, but you’ve probably felt them. They’re the inflammatory substances that limit blood flow to your uterus and are responsible for some cases of cramping. 

Pain-relief medicines such as ibuprofen block the production of prostaglandins, but exercising is a healthier way to prevent them. 

Working out not only boosts blood flow to your uterus, but it also sparks the production of feel-good (and pain-relieving) hormones called endorphins.

Exercise can cause irregular periods

Working out requires you to tap into the energy needed to run your body daily. When your body doesn’t have enough power to keep your systems running, it bats off the nonessentials - in this case, your reproductive system. 

A region in the brain called the hypothalamus slows down the release of hormones responsible for ovulation, so your period may not arrive when you expect it. 

This usually only occurs with intense, strenuous exercise coupled with a low-calorie diet but the type of training you're doing can play a role, too. Endurance athletes such as marathon runners or triathletes are much more likely to experience irregular periods because that type of exercise has a greater stress on the body. 

In summary

Skipping one or two periods in a year is pretty normal for most women, but any more than that might be a sign that something else is going on and you should speak to your doctor.