Highs and lows are a feature of any athlete’s career, but for some female contestants, these peaks and troughs in performance may come more regularly – driven by hormonal changes associated with their menstrual cycles.
Now, the English Institute of Sport (EIS) is seeking to level the playing field through the rollout of regular saliva testing to track the rise and fall of two key drivers of these monthly changes: oestrogen and progesterone.
Because of the hormones involved, the menstrual cycle underpins many aspects of a woman’s health, from her bone strength to her fertility, immune system and mental functioning. “If they don’t have a healthy menstrual cycle, it means for whatever reason, something’s not quite right,” said Dr Richard Burden, co-lead for female health at the EIS.
Some women also experience symptoms related to their menstrual cycle such as low energy, pain or bloating. According to one recent study of female rugby players, 93% of them reported cycle-related symptoms, and 67% thought these affected their athletic performance.
Even so, the menstrual cycle is among the least studied aspects of human biology. Last year, Chelsea Women became the first football club in the world to start tailoring its players’ training to their menstrual cycles, although there’s little evidence that this is effective.
“There’s a very thin layer of evidence to suggest that there may be ways in which you can manipulate training based on where someone is in their menstrual cycle. The problem is that if you’re not measuring the hormones, you don’t actually know what’s happening. Just because you have a normal cycle length, doesn’t mean that your hormones are behaving in a normal fashion,” Burden said.
“Also, all of the research right now is very generalised, and applying what is happening in a general population to an athlete who is performing at the highest level she possibly can doesn’t really cut it.”
The EIS is now seeking to change this, in the hope of providing more precise and individualised support to female athletes. By tracking their hormones, Burden and his colleagues hope to gain a better insight into how athletes’ training schedules are affecting their health, or their recovery from injury. If abnormalities in their cycles are detected, this could lead to nutritional or other interventions try to correct them.
Last summer, the EIS launched a pilot study involving 15 elite athletes from eight sports, including football, tennis, rowing, cycling, gymnastics and modern pentathlon, which suggested that alternate day hormone testing could provide real-time actionable data.
Though the research is still at a very early stage, the idea is to roll out the technology more widely post-Tokyo, to test whether it really could improve women’s general health and performance in the run-up to the Paris Olympics in 2024.
“I think it’s exciting that girls are talking about how their period affects them, and that we’re finding ways to not fix it, but improve and manage symptoms,” said Pentathlon GB athlete Jess Varley.
Although some athletes already use period-tracking apps, these don’t measure hormones; indeed, any form of regular hormone testing has been difficult, because until recently, this required samples of blood. The Hormonix system, which was developed by Kent-based Mint Diagnostics, in collaboration with the EIS, uses saliva testing instead.
During the pilot study, the athletes took a sample of their saliva in a tube, and then stored these in their freezers until they could be collected and analysed, after which the data was fed back to them. However, Mint Diagnostics is working towards point-of-care testing, where saliva samples could be loaded into a desktop machine, and results delivered almost immediately, allowing coaches to process athletes’ saliva samples and provide real-time feedback about their health.
Also under development is saliva sampling to measure hormones found in both male and female athletes, such as cortisol and testosterone. These could be used to monitor their response to training and recovery, and potentially enhance it.
Case studies
Katy Dunne – professional tennis player
Katy, 26, had fairly regular periods until she was about 14, when she started eating less, on top of competing in junior tennis tournaments. As she grew older, her periods became increasingly sporadic, until they stopped completely. A turning point came in her early 20s, when Katy’s coaches noticed that she wasn’t gaining any strength, even though she was training hard. “They kind of put two and two together and had a conversation with me about my fuelling, and whether I wasn’t eating enough,” she said.
With professional support, Katy began eating more, and gradually her periods returned. “I’d say that I was happy, because I’d gone from having no periods, to having maybe eight or nine in a year,” she said.
Even so, Katy’s coaches were concerned about the low-level injuries she kept sustaining: bruising on her pubic bone; groin strain; stomach strain; a shoulder injury – which were hampering her progression with training.
“The biggest risk to performance in any elite sport is loss of training time. The more days you lose, the probability for high performance gets smaller,” said Burden at the EIS.
Katy was referred to Burden, who enrolled her in the Hormonix trial. This revealed that, although she had the appearance of a healthy menstrual cycle, her hormones were not fluctuating in the way that they should.
“The menstrual cycle underpins most of the physiological systems in a female, and someone like Katie needs all of those physiological systems to be firing 100% because of the training that she’s doing, and the performance that she’s striving for,” said Burden. “If her hormones aren’t really supporting that, then there may be consequences for things such as her immune function and injury susceptibility.”
Katy said: “It has enabled me to see that I need to make another change and keep improving on how I’m fuelling my body. As a result, we’ve brought on more support in a nutritionist, to start improving that.”
Jess Varley – Pentathlon GB athlete
Jess, 26, has always had regular periods, arriving every four weeks without fail. However, she’d noticed that in the three or so days running up to her period, she’d suffer from stomach cramps, feel less energetic and her athletic performance would suffer.
“The most obvious discipline that it has affected is fencing, because you have to be so mentally switched on and aware of what’s happening around you, and then physically explosive in the right moment,” said Jess. “My fencing performances were just very up and down, depending on when they fell in my menstrual cycle.
Jess was also enrolled in the Hormonix trial, which revealed that her menstrual cycle was entirely healthy. Even so, this information was extremely useful, because it ruled out hormonal abnormalities out as the source of her menstrual symptoms. Now, Jess and her support team could start adjusting other aspects of her training and diet to see if this had any impact on her menstrual symptoms, while ensuring that these interventions weren’t adversely affecting her health.
“We tried changing my diet, so we cut out pasta and bread, and lowered [other] carbs a little bit, but not excessively. And because we were tracking the hormones, we knew that I was still fuelling enough day-to-day, to cope with the volume of training that we’re doing,” said Jess. “We found that cutting out that form of carbohydrate, made a huge difference to my symptoms.
“It has given me the confidence to go into competitions and not worry about where I am in my hormone cycle. And to know that I am fuelling correctly and to trust that I can perform at the best of my ability now, any time, which is exciting.”