Explained: How the menstrual cycle affects female athletes’ performance

When Indian boxer Mary Kom reached the semi-finals of the women’s 51kg category at the 2012 London Olympics, she had assured herself and India of an Olympic medal.

But for the former world champion, not only was there a tough opponent in eventual gold medallist and home favourite Nicola Adams, but her own body began revolting against her. A day before her semi-final bout, Kom’s periods began, recalled Dr Nikhil Latey, the former head of sports science at Olympic Gold Quest, who was part of Kom’s team back in 2012. On the day of the bout, Kom was on her second day, a typically tougher day for the boxer.

“You’re going to be a little bit weak, a little bit slow, your muscles are going to be sluggish and it creates a problem,” said Latey to Scroll.

In sports like weightlifting and boxing, where the difference between a good result and elimination from the contest is a matter of small margins, and not being at a 100% at every point in the competition can be disastrous.

Kom ended up losing the semi-final and won the bronze medal. Latey recalled how they realised that she was moving just a fraction slower and her punches were less impactful because of the toll her menstrual cycle was taking on her body.

More recently, after her competition ended at the 2024 Paris Olympics, Indian weightlifter Mirabai Chanu also pointed to the fact that she was on her periods as a possible reason for a slight dip in form. She finished fourth in the women’s 49kg event, missing out on a podium spot by just one kilogram.

The menstrual cycle for female athletes is a natural process around which they have to structure their training and manage their nutrition. But what actually happens in the body during this cycle?

The menstrual cycle explained

Dr Poorni Narayanan, a practicing gynaecologist and obstetrician in Bengaluru for the past 25 years, explained that the menstrual cycle is to do with the reproductive system, the ultimate goal of which is to produce offspring.

“The body starts preparing for this generally between the ages of 11 and 14 for girls, where the uterus forms a lining called endometrium,” Narayanan said to this publication. “This is done in response to the functioning of the ovaries, which every girl has two, that houses millions of eggs.

“When the egg releases from the ovary, the uterus starts to prepare the lining awaiting fertilisation by sperm. And if the egg does not get fertilized, it throws out that lining along with blood a couple of weeks after the egg release – which is menstruation.”

According to Narayanan, the cyclical nature of menstruation, which usually follows the 28-day pattern, does not settle for quite a few years for some girls after they get their first period.

The entire body is impacted during the menstruation phase because it involves the uterine muscles squeezing out the endometrium to clear the uterus of the lining and prepare for the upcoming cycle. Along with the lining there is also additional blood loss which contributes to fluid loss from the body.

“When one wants toothpaste out of the tube, it is not sufficient to just open the tube and wait,” explained the gynaecologist. “One has to squeeze the tube and make sure the paste is ejected.”

“In the same way, the uterus squeezes sufficiently enough to eject the lining. This causes muscle cramps, pain and discomfort in the pelvic region.”

For some women, the muscle is harder than normal which sets off the pain nerve fibres and they experience more pain. This could also lead to nausea, loose motions and giddiness among other symptoms.

Generally there is no discomfort experienced during the proliferative phase which lasts about two weeks or 14 days. Around the time of ovulation, the fluctuation in the ovarian hormones can make the body vulnerable to possible muscle injury.

“The muscles become more amenable to some stretching or pulling because of the decreased neuromuscular control around the pelvic area,” said Narayanan.

“Right before the menstruation phase starts, the level of hormones like oestrogen and progestrone fluctuate once again which could cause some amount of fluid retention and mood swings, known as pre-menstrual symptoms.”

How do athletes manage their periods?

Nisha Miller, a former Olympic swimmer for India, was educated about the knowledge of birth control pills when she moved to Australia for training at the age of 18.

Having received a scholarship from the International Olympic Committee to go train there, Millet had secured qualification for the 2000 Sydney Olympics and decided to practice in the country ahead of the event.

After discussions with her father and team, Millet and her entourage decided to approach the West Australian Institute of Sport in Perth to enquire about how to safely control her periods so that they don’t affect her performance or occur during the Olympics. At that time back in 2000, the only way to do this was to take birth control pills.

Birth control pills are a form of oral contraceptives that essentially halt the ovulation phase from occurring and prevent sperm from entering the cervix for possible fertilisation. In the case of athletes, they are used to accurately predict when the menstruation phase would occur and accordingly schedule it around important tournaments and competitions.

“Birth control is very normal and even 24 years ago, it was common in the West for athletes to use it to control their periods,” Millet told Scroll. “Obviously you don’t want to have your periods [during the Olympics]. They talk about your ligaments and tendons not being as firm and your iron levels might go down [because of the excessive blood loss].

“But it’s very normal to compete in smaller competitions while on your period. Obviously it makes a difference in competitions like the Olympics, but using birth control just for that period of time and then your periods go back to normal, so that was no concern for me,” she added.

Latey, who worked with Indian athletes like shooter Apurvi Chandela and shuttler Saina Nehwal during his time at Olympic Gold Quest, stressed on consultations with doctors, gynaecologists and physical trainers ahead of important competitions for female athletes.

“I would not recommend messing around with your hormones [for extended periods of time],” explained Latey. “But for the purpose of a few days like during the Olympics, as long as you’re under supervision and use those medicines for the sake of controlling your period, it should be fine.”

Latey also included the need to discuss and tailor both training and nutrition according to how each individual female athlete experiences the menstrual cycle.

“When you’re a junior athlete and your cycle hasn’t settled, the coaches can get frustrated at how to manage your health,” Latey added. “As you get older perhaps, you have a more settled team and then you can speak about it openly and discuss ways to manage it safely.”

Also read: Why weight cutting is harder for women in combat sports

Then and now, the changes made

During her playing days a decade ago, former badminton player Aditi Mutatkar was never able to discuss how to manage her training during her periods with her seniors or coaches. Although the 2010 Commonwealth Games silver medallist never knew the importance of tracking her periods, there wasn’t a culture of speaking about the impact of periods for female athletes during her time.

Now heading the athlete and women initiatives at Simply Sport Foundation, a non-governmental organisation, Mutatkar has been conscious about using her experiences to help current athletes and girls in their management of their menstrual cycles.

“Back then, we couldn’t use periods as an excuse to skip training,” recalled Mutatkar. “But now, we understand a little more about the physiology and how it can impact athletes.”

Mutatkar added that she later leant that she was a thalassemia minor, meaning she could have been anemic, causing fatigue during periods.

“But nobody connected why I couldn’t recover from heavy training during my periods and why I felt more tired,” she said. “I was also an athlete that got injured frequently, and you know how your body can get affected during different phases of the cycle. For each athlete it is different.”

Mutatkar also pointed out that the hesitancy around discussing menstruation in public leads to many junior athletes not knowing about the treatments and medication available to manage their menstrual symptoms better for important competitions.

Millet, who now runs a swimming academy in Bengaluru, had talked about how she sits down with parents of children who are interested in enrolling, but have doubts about allowing their daughters to compete in swimming. The former Olympic swimmer has conversations about how it is possible to compete in sport, swimming especially, while managing your menstrual cycle with the right training and nutrition.

Neha Aggarwal, a former Olympic table tennis player and currently the head of partnerships at Olympic Gold Quest, also highlighted how there was very little awareness about proper nutrition and hygiene during menstruation earlier.

Another aspect of managing competition during your menstrual cycle includes how it affects your mind. Aggarwal pointed out that during national competitions, the lack of proper hygiene like clean bathrooms and running water would take a toll on their mental state if they were competing on their periods.

Echoing Millet and Mutatkar, Aggarwal said that “nobody had any clue what was going on” regarding periods and menstrual cycles.

“Some coaches would get angry if girls, especially those who had heavy periods, would take a few days off training,” Aggarwal said. “Now there is information about taking pills that can control the level of bleeding which definitely impact how female athletes compete and train.”

With more information being made available to girls and the stigma around menstruation slowly being eliminated, research is ongoing on the nuances of the menstrual cycle on the female athlete body, especially while they are in-competition.