When sports scientist Dave Hamilton began monitoring the testosterone levels of an international women’s ice hockey team, it was to measure how the athletes were coping with their new higher training loads. Hamilton took daily saliva samples from the players for three weeks, one in the morning and one in the afternoon after physical activity. The study didn’t raise any red flags about their training plans, but it did provide some unexpected results.
“What we found was that relative to a sedentary population, [the women] had high testosterone levels,” said Hamilton, who now serves in a similar high-performance role with the Tampa Bay Buccaneers. “We also found that those who took oral contraceptives had lower testosterone levels compared to those who didn’t.” In fact, women who didn’t take oral contraceptives had, on average, 35 percent higher testosterone levels than those who did. who took the pill.
It’s a fascinating insight into the differences in testosterone levels in female athletes. At a time when the “T” word has become the focus of a heated debate over whether trans and gender development differences (DSD) athletes are allowed to compete in women’s sport – with testosterone levels often being the determining factor – this is Hormone often the crucial factor misunderstood that it exclusively affects men.
Much of the lack of understanding stems from historical underinvestment in sports science research on women.
Unlike current testosterone-trans measures in sports, which measure levels in the blood, Hamilton’s study focused on saliva, or “free” testosterone, which provides a much smaller amount of the hormone. The results revealed sharp changes in response to a variety of stimuli – from exercise and music to coaching feedback, sleep, in a group or alone.
“We guided our program knowing that testosterone responds to both physical and environmental stress,” Hamilton explained. “There is a lot of research showing that when you win testosterone levels go up and when you lose testosterone levels go down. If you think a normal woman has about 20 to 40 pg/mL of free testosterone, you could go from a record of 25 to 55 pg/mL.”
However, there was another significant finding. “We had a large portion of our team reporting testosterone levels in the 80 to 100 pg/mL range, which is in line with the average male testosterone level,” Hamilton said. “There was also nothing in our data to suggest that when ‘x’ had the highest T scores, she was the best athlete. It just wasn’t a thing.”
On the contrary, high levels of testosterone in athletic female populations — entering male ranges — have been found before, according to a 2014 study published in the Journal of Clinical Endocrinology.
Based on blood samples from 693 athletes, the study found that 16.5 percent of the men had low testosterone levels, while 13.7 percent of the women had high testosterone levels, with a complete overlap between the sexes. The newspaper criticized the then International Olympic Committee’s definition of normal testosterone levels for a woman as “unsustainable”.
“There are many men with low testosterone who are good athletes,” said Peter Sonksen, Professor Emeritus of Endocrinology at St Thomas’ Hospital and King’s College, London, who co-led the study and whose research for the International Olympic Committee eventually led to develop an anti-doping test for human growth hormone.
“And there are many women with very high testosterone levels who are also good athletes. The simple problem is always that testosterone makes them super athletes, but that’s B——-.
The issue is so complex and divisive that the IOC — largely due to a lack of data — is now allowing global sports federations to set their own trans policies. It had previously recommended that trans women should keep testosterone levels below 10 n/mol per liter for at least 12 months in order to compete, while the Union Cycliste Internationale requires cyclists to stay below 5 nmol/L for a period of time must be at least 12 months. “It’s an incredibly sensitive area and one where they’re intentionally simplifying and messing with the science,” Sonksen added.
The IOC defended its approach to the “evolving issue” of trans women in sport, stressing that recent studies have not provided a consensus on how testosterone affects performance in all sports. It added: “At this point in time, there is no single correct answer from science, as the scientific evidence needs to be specific to each sport or discipline and how competitive advantage is to be measured there.”
The population of trans women is so small that nearly two decades after the IOC originally ruled that trans athletes could compete in the Olympics provided they had sex reassignment surgery, the sport is still in the early stages of its exploratory mission. to understand if trans women in sport have an advantage over cis women. At the heart of the debate – which intensified earlier this month after trans cyclist Emily Bridges was banned from riding in the National Omnium Championships – is testosterone.
A study published last year in the British Journal of Sports Medicine found that trans women who had undergone hormone therapy for a year continued to have an athletic advantage despite a 15 to 31 percent drop in physical capacity.
Based on transgender men and women who served in the U.S. military, it found that the 15-31 percent athletic advantage trans women displayed over their cis women before they started using gender-affirming hormones feminizing therapy decreased. However, after one year of testosterone suppression, trans women still had a nine percent faster mean running speed.
“It becomes a discussion of how low and for how long,” says Dr. Christina Marie Roberts, a pediatrician and associate professor at the University of Missouri-Kansas City who led the research. She points to a variation in cis women that has flown under the radar in the context of discussion of fairness in sport.
“The IOC originally selected 10 nmol/L because that is the highest naturally occurring testosterone level in women. Some women with polycystic ovary syndrome have higher levels of testosterone than other women. Testosterone, wherever it comes from, is an advantage, so there will be an advantage in women’s sport anyway.”
Charlie Martin – the British racing driver who hopes to become the first transgender driver to compete in the 24 Hours of Le Mans – who competes in mixed-gender motorsport, believes the understanding of testosterone in trans women is often misunderstood. After a medical reorganization that included a full sex reassignment, her body is not producing any real amounts of testosterone. “It’s these simple things that most people don’t think about,” Martin says of the debate over whether trans women should compete in women’s sports.
She adds, “I would say my strength is that of a cis woman who works out as much as I do and eats well and works out. That’s my experience and the experience of pretty much every trans woman I know.”
At the forefront of research in this country is an ongoing study – in which Bridges is participating – at Loughborough University. dr Emma O’Donnell, a lecturer in exercise physiology there, highlights the challenges of the work. “Unfortunately, with such a small transgender athlete population and the differences in the physiological demands of different sports disciplines, it will be several years before we have the data needed to inform sports governing bodies so they can create evidence-based guidelines on transgender sports participation. ”
O’Donnell says testosterone remains an essential element of the study. “Testosterone is an important parameter to consider,” O’Donnell said. “Testosterone levels increase almost 20-fold during male puberty, marking a time of significant physiological changes in men. The testosterone load that an adult trans woman will have been exposed to prior to initiating testosterone-lowering hormone therapy is therefore an important consideration when attempting to understand the effects of hormone therapy on athletic performance.” At this time, these effects are unclear.
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