When is the best time to exercise during your cycle? Do you need to change your diet during your cycle to help with exercise? Dr Amélie Roland, Vhi Women’s Health Specialist, answers all our questions about exercise and recovery during the menstrual cycle. 

Do the stages of the menstrual cycle impact exercise performance? 

There are two disclaimers I want to share before getting into detail on this question:

1. It’s important to note straight off the bat that it’s very difficult to study how the menstrual cycle affects exercise, sports or any kind of athletic performance. It has been attempted more in the last few years, but testing is complex, and this makes it hard to gather scientific data on the topic. 
2. There are vast differences in how the menstrual cycle is experienced from woman to woman. This includes cycle length and regularity, PMS symptoms and impacts on lifestyle. 

This means, unfortunately, there are no hard and fast rules about what each stage of the menstrual cycle does or doesn’t do to women’s exercise performance. The luteal phase (the fourth phase, or the phase before you menstruate) is the only slight exception. The luteal phase is the only stage of the menstrual cycle where, scientifically, we know that measurable changes occur across the general female population ─ a woman’s body temperature and heart rate can increase each time she’s in the luteal phase. This doesn’t mean there will be any impact on their exercise performance, however. But there are some general trends regarding the menstrual cycle stages that we see individually and anecdotally (personal accounts rather than facts or research) that we can discuss here. 

The psychological impact of the menstrual cycle on exercise 

Something we see across the female population regarding the menstrual cycle and physical performance is the psychological impact. This is known as the rate of perceived exertion. It’s basically a measure of how hard someone feels they are working during physical activity. We’ve seen that when female athletes push themselves as hard as they can during their period, some will feel that it's much more challenging than when they aren’t menstruating. Also, they may feel their time was slower or their performance was lacking, but most of the time, the data shows  there is no actual change in their performance. Again, this will vary from one woman to another but is commonly experienced to some degree. 

What physical impacts on exercise can some women experience during their cycle?

If we look at women individually, rather than a general population or collective, we can sometimes see differences during the follicular phase (just after menstruation and before ovulation) and during ovulation. When talking about endurance sports and aerobic sports, some people might feel like they can push more during the follicular and ovulation phases, as opposed to the luteal phase. If you're talking about strength training, there is a tiny bit of evidence (but again, no major consensus) that people can recover better and push a little bit more in terms of weight during the luteal phase. But because this all varies from woman to woman, the best advice is for each woman to track their own cycle (there are lots of apps for this) and how they feel in terms of energy, physical ability, mood, PMS and so on. You can then learn how performance and recovery feel in each phase and build your own routine around that. 

Top tip: No matter what stage of your cycle, exercise will always have beneficial effects. The key is figuring out what kind of exercise, intensity and duration works best for you and your body during each phase of your cycle. 

Are there tips for women exercising or taking part in a race during their period?

Yes, there a few things that women can try that may help them:

• The first thing is to make sure you’re as comfortable as possible. Think about what sanitary protection you’ll use ─ testing different methods before a race is a good idea.
• Consider the colour of your workout clothes so you can have extra peace of mind, if staining is something that would bother you. 
• The week before your period, a diet rich in omega 3 (such as oily fish, walnuts, chia seeds, avocado) helps with hormonal balance and period pain for some women. 
• Remember, although you might worry you can’t perform as well (the rate of perceived exertion, mentioned above) during your period, the numbers show you most likely can. If you’re taking part in a race, trust in yourself and the training you’ve done! Equally, don’t be hard on yourself if you just don’t feel up for pushing yourself.
• During the luteal phase, women need an increase in energy intake, varying from +90 to +590 calories per day. Make sure you listen to your body’s hunger cues so you’re fuelling yourself for exercise. 

Are you a seasoned runner or planning to start? Have a read of my blog, ‘Top nutrition and energy considerations for female runners’, for some tips and insights. 

Key takeaways:

• Scientifically speaking, there are no hard and fast rules about what each stage of the menstrual cycle does or doesn’t do to women’s exercise performance. Instead, the effects are individual to each woman. 
• During the luteal phase, a woman’s body temperature and heart rate can increase. 
• Many women will feel their ability to exercise during their period is decreased, but this is mostly psychological. 
• Some women feel like they can push more during the follicular and ovulation phases. 
• During the luteal phase, women need an extra 90 to 590 calories per day, so keep this in mind when fueling your body for exercise. 

This content is for information purposes only and is not intended or implied to be a substitute for professional medical advice, diagnosis, or treatment. Always seek advice from your GP or an appropriate medical professional if you have concerns about your health or before commencing a new healthcare regime. If you believe that you are experiencing a medical emergency call 999 / 112 or seek emergency assistance immediately.