Can too much exercise stop your period?

Bottom lineYes, very intense training combined with not eating enough can make periods irregular or stop them, part of a pattern called relative energy deficiency in sport (RED-S); it is a signal to eat more and train less, and stopped or very irregular periods should be checked by a clinician rather than treated as a normal side effect of being fit.

Yes. Very intense or high-volume training, especially when you are not eating enough to match it, can make your periods irregular or stop them altogether.

Why it happens

When the energy you burn consistently outstrips the energy you take in, your body lowers the hormones that drive the menstrual cycle to conserve resources. The result can be lighter, irregular, or absent periods. This is part of a recognised pattern called relative energy deficiency in sport (RED-S), which also affects bone health, mood, and performance.

It is most common in people doing a lot of endurance training, or combining heavy exercise with restricted eating.

What to do

• Treat missing periods from training as a signal, not an achievement - it usually means you need to eat more and train less.
• Make sure you are fuelling enough for your activity level.
• See a clinician if your periods have stopped or become very irregular. Do not assume it is a harmless side effect of being fit.

Moderate, regular exercise does the opposite - it supports a healthy cycle and eases symptoms. The problem is specifically the mismatch between very high training loads and too little fuel. See can exercise affect your period for more.

This is general information, not medical advice.