Is it harder to run fast and lift things while you're on your period? A lot of athletes say yes, but the science is lagging behind, so it's hard to know whether there's a real performance dent or what you should do about it. Here are some tips from top athletes that might help.
Picture: Kurt Bauschardt/Flickr
BBC Sport interviewed several elite athletes, including women's marathon world record holder Paula Radcliffe, about what they do when something important (like, oh, say, your Olympic race) falls on the worst day of the month.
Radcliffe's take is simple: "I broke the world record [while on my period] so it can't be that much of a hindrance, but undoubtedly that's why I had a cramped stomach in the final third of the race and didn't feel as comfortable as I could've done."
Jessica Judd, a middle-distance runner, says her performance varies wildly depending on where she is in her cycle; that's why, she says, she ran a 3000m race in nine minutes and 15 seconds, then a week later ran the same distance in nine minutes flat. For a key race in 2013, team doctors gave her norethistrone to delay her period. Radcliffe says the medics should have known that this would make her performance worse, not better.
She told BBC Sport that the doctors' decision was based on what little scientific knowledge they had on the subject, but they simply don't have the whole story. There haven't been large studies on how to control your period to promote better athletic performance, because only small numbers of elite athletes have even tried.
Recent research suggests that your cycle probably doesn't have an effect on strength or aerobic performance, but endurance may suffer in the second half of your cycle (that is, the two weeks just before your period). The research is mainly on women with natural cycles, so if you're on the contraceptive pill, the science is inconclusive.
So, what can you do about it? While we wait for more science to roll in, getting to know how your performance changes throughout the month is going to be more helpful than piecing together a plan based on scraps of research that don't definitively answer the question. Here are some more tips that may help.
- Go easy on yourself. Don't assume you'll perform badly just because it's That Time of the Month. Lots of things can affect your performance in sports, and you may have better return-on-investment focusing on those other aspects.
- Keep a training diary to track what's going on. Maybe your mile time does really dip every 28 days, or maybe workouts are harder when you're crampy but your finish time is the same. Careful records can also help you figure out whether there's something you can do to minimise the symptoms, like if it helps to hydrate more on those tough days.
- Consider telling your coach/trainer or modifying your workouts if you know you won't be able to do your usual work, or lift the same weights, those days.
Sadly, whether you tell a trainer or teammate is, the athletes noted, a double edged sword. It helps to keep the subject from being taboo, so athletes can compare notes and learn from each other. On the other hand, badminton champion Gail Emms remembers a teammate who had her period when she lost a doubles competition. The teammate's (male) partner, she says, is "still fuming" because he thinks that's why they lost.
Curse or Myth - Do Periods Affect Performance? [BBC Sport]