Periods and energy · For ages 13–17
Why do I become so tired during my period?
Some people feel more tired around menstruation. If you bleed heavily or the tiredness is severe, it may also be important to investigate whether you have an iron deficiency.
What happens?
There can be many reasons for feeling tired
Energy levels can vary through the menstrual cycle. Pain, poor sleep and other menstrual symptoms can also make you tired.
If you have heavy bleeding, your body may lose a lot of iron. Iron is used, among other things, when the body makes red blood cells that carry oxygen.
Iron deficiency or anaemia can cause fatigue, dizziness and shortness of breath.
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Which describes what you have noticed?
Choose the option that fits best to see guidance on what you can do next.
Energy can vary through the cycle, and pain or poor sleep can also make you more tired.
Pain, changing products at night and losing sleep can drain your energy. Look at what is actually making the days difficult rather than expecting a particular energy level at each point of your cycle.
Breaks, regular meals and relief of symptoms may help. If tiredness increases or continues between periods, other possible explanations should be assessed.
Severe or persistent fatigue should not simply be dismissed. If you also bleed heavily, it is worth asking a doctor whether your iron levels and blood count should be checked.
Explain whether you miss activities, struggle through the school day or feel tired throughout the month. Heavy bleeding can cause iron deficiency, but sleep, illness and other factors may also contribute.
Your GP can assess relevant tests and follow-up. You do not need to begin taking iron supplements yourself to find out whether that is the explanation.
Fatigue together with dizziness or shortness of breath can be seen with iron deficiency or anaemia, among other conditions. It is sensible to tell a doctor.
Describe whether it happens during ordinary activities, when you stand up or even at rest. Your bleeding pattern and how long symptoms have lasted are also relevant.
An assessment should consider the whole situation rather than just the cycle. Sudden severe breathing difficulties, fainting or becoming acutely unwell require urgent help as described on the page.
What can you do now?
If you are much more tired than usual, also explain how much you bleed, your sleep, any dizziness and how the tiredness affects your daily life.
Your GP can assess whether you need a blood test for iron deficiency or other causes. If you suddenly become seriously unwell, faint or have difficulty breathing, you need urgent help.
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