Despite that fact that we make up half of the world’s population, research into how our menstrual cycle affects our fitness levels is thin on the ground. We sought some expert opinion…

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A lot of questions emerged from Chinese swimmer Fu Yuanhui’s remark that she didn’t reach her full potential in the Olympic 4x100m medley relay last week because she had her period. There was puzzlement in her homeland as to why the pool didn’t turn red (only around 2% of Chinese women use tampons) and how she was able (allowed?) to swim at all, which is reminiscent of the Georgian swimming pool that banned women from swimming during menstruation just a week earlier, on account of the potential for periods to ‘contaminate’ the water. The ignorance, and of course the struggle, is real when it comes to periods.

The thing is, and not to excuse the shame and stigmatisation attached to periods in many parts of the world, menstruation is a relatively unstudied subject, particularly in the sporting arena. According to a review by the British Journal of Sports Medicine of more than 1300 sports and exercise studies, research participants were on average 61% men and a measly 39% women, and it’s said that this degree of imbalance is an issue in medical research generally, which is deeply worrying where drugs trials in particular are concerned. Given that we’ve had periods since the dawn of time, and that menstruation is essentially responsible for the fruition of humankind (getting a bit melodramatic there but...true story), it’s simultaneously frustrating and frankly a bit dangerous that we’ve not been put under the microscopic more intensively.

Of the studies that have been published, findings from the Neuralplasticity Laboratory at the Rehabilitation Institute of Chicago indicate that menstruating women are more prone to leg injuries, as soaring oestrogen levels can slow down muscle reflexes, meaning that more women typically suffer the likes of ACL injuries than men (women are reportedly twice as likely as men to incur this type of injury at certain points in their menstrual cycle). Research suggests that fluctuating hormones can also affect our metabolism and body temperature, which could both have a bearing on our fitness levels, while iron deficiency is another little studied factor that can affect the physical performance of menstruating women. Irregular periods amongst athletes are also relatively unchartered waters in the sports research domain, while the wave of fitness apps and gadgets that initially launched didn’t account for hormonal shifts during the menstrual cycle at all, which is inconsiderate to say the least but not surprising when considering the significant gaps in data on the topic.

Tides are beginning to turn, with UCL and St Mary’s University conducting surveys amongst 789 female athletes, in addition to a group of London Marathon runners, on whether they feel that their menstrual cycles affect their performance. Tellingly, of a group of 1073 women in total, close to a third felt that their physical performance was affected, and 36% disclosed that they suffered from very heavy bleeding. Bleeding heavily can lead to iron deficiency aneamia, symptoms of which include fatigue, shortness of breath and heart palpitations, which would have obvious negative implications on sporting performance. Georgie Bruinvels of St Mary’s University is currently studying the effects of the menstrual cycle on iron deficiency in female athletes for her PhD project, with the help of crowdfunding.

With little decisive evidence either way as to how having our periods could affect a PB (after all, Paula Radcliffe broke a world record during the week of her period), we asked sporting, wellbeing and medical experts for their tips on how to ride out period week, but how you go about scheduling your workouts is of course personal to your own body, menstrual cycle and experiences.

The medical opinion

Dr Jane Leonard, GP

“Exercising during this time will not cause any harm, but don’t be too hard or tough on yourself. Always listen to your body, allow yourself adequate rest and you’ll feel re-energised for your next gym session.”

“Having said that, exercise naturally releases endorphins in your body. This can be so beneficial if your mood is on the lower side of ‘normal’ and you’re feeling more irritable both during the PMS stage and when your period actually arrives.”

“It’s worth noting that you may also feel bloated around the time of your period- this is due to raised levels of oestrogen which can lead to fluid retention, making your body, feet, hands and fingers feel swollen. As well as leaving you feeling sluggish, you could also find that you particularly crave sugary and carby foods. Try not to alter your diet too much during menstruation to keep energy levels steady- a treat is fine, but moderation is key.”

“Finally, I think education regarding the menstrual cycle should also be encouraged to help women understand their bodies and how to optimize their health and wellbeing. In particular if you tend to bleed heavily, it’s worthwhile to visit your GP for a full assessment and to check your full blood count to ensure that you’re not anaemic.”

The PT opinion

Katie Gray, Personal Trainer and founder of Train.Tone.Transform

“For me personally I continue to exercise as normal throughout my period as thankfully I don't suffer from crippling cramps, although I know that some others do. I tend to have some bloating with my cycle, but to be honest I'm used to this having suffered with IBS for years and so I know how to deal with this with exercise choices. When I experience bloating I find that sticking to cardio is more comfortable for me than resistance training, therefore I would pick either a spinning class, the stairmaster or interval sprints or an incline walk on the treadmill. I would also avoid ab exercises as trying to crunch or twist can be super uncomfortable!”

“Some tips I recommend to clients who continue to train during their period are as follows:

Take a magnesium supplement. Magnesium acts as a muscle relaxant and so can be super helpful in relieving painful cramps or lower back pain.

Increase your water intake. During our cycle we tend to hold on to an increasing amount of water, which in turn can make us feel heavy and bloated. Surprisingly increasing our water intake reduces water retention, so make sure you are drinking at least two litres a day.

Listen to your body. If you can't face your usual training that day, don't do it! Switch up your rest days, or do something more gentle such as a walk, yoga or pilates. You don't want to add unnecessary stress to the body by pushing yourself too hard or over training.

Go to bed early! Sometimes our period can zap the energy out of us meaning that we have none left to exercise. Combat this by going to bed earlier than usual to give you an extra boost in the morning.”

Esmée Gummer, personal trainer and  1Rebel instructor

“'When you feel tired and that you can't be bothered to exercise, surprisingly HIIT training could be your golden choice. High intensity interval training means expending short bursts of energy over a period of time. 20 seconds of your maximum effort with a short break will keep you engaged and your energy levels will go through the roof. Or for that extra release, try boxing - there is nothing better than beating a bag down and letting all your troubles melt away. Remember that your body temperature is higher than usual, so sweat out that heat and finish with a cool shower.''

If you don’t feel physically up to taking on a punch bag, Esmée has a few more gentle back ups:

“'Bloating is horrid when you are on your period, especially when you are exercising. It makes you feel a lot worse than you otherwise would. Swimming is a great way of exercising in a low impact way, and it’s a good way of naturally relaxing tension through motion.''

“Yoga is also beneficial for not only relaxing the body and mind but also to release muscle tension in the back. The downward facing dog in particular will loosen tense muscles.''

Which leads us to...

The yogi opinion

Libby Limon, Yoga Teacher and Nutritional Therapist

“I don’t personally practice during the first few days of my cycle, but that is more because it’s really not what I feel like doing and it gives my body and mind a natural break. I would say listen to your body and do what feels good. Traditional advice is to avoid inversions during menstruation, as this may be linked to endometriosis, although I have never seen any evidence of this, so it could well just be a yogic old wives tale…”

Whether you feel that your period affects your fitness levels or not, taking care of yourself by staying hydrated, getting enough sleep and eating a balanced diet will all serve you in the strength and stamina department. If there was ever a time for a bit of TLC, whether that’s taking a rest day or treating yourself to boutique fitness class, it’s now. No excuses.

PMS sufferer? For advice on treating it holistically,  see our SOS page

Follow Katie on Instagram  @katiegrayfit , Esmée  @esmee_gummer , Libby  @libbylimon  and Anna  @annyhunter