The current scientific literature suggests that women’s bodies are less adept at handling the physiological stresses caused by intense exercise than those of biological males. However, a recent feat by a kickass team of female adventurers named the Ice Maidens suggests otherwise.
In a presentation at the Society for Endocrinology annual conference in Glasgow this week, researchers from the University of Edinburgh and the UK Royal Centre for Defence have shared pre-publication results of a study that monitored the Ice Maidens’ bone strength, weight, and hormones before and after their record-breaking two-month ski journey across Antarctica.
"Our findings contain some potentially myth-busting data on the impact of extreme physical activity on women. We have shown that with appropriate training and preparation, many of the previously reported negative health effects can be avoided," lead author Dr Robert Gifford said in a statement.
"These findings could have important relevance for men and women in arduous or stressful employment, where there is concern that they are damaging their health. If an appropriate training and nutritional regime is followed, their health may be protected."
Completed between November 2017 and January 2018, the Ice Maiden expedition was a 1,700-kilometer (1,000-mile) coast-to-coast trek across the frozen continent powered by nothing other than muscle and determination. All active or reserve officers in the British army, the women traveled in extreme conditions characterized by temperatures as low as -40℃ (-40℉) and blistering 96-kph (60-mph) winds for 61 days. With no backup and only two resupply caches along the way, the athletes towed all their own gear and food on 77-kilogram (170-pound) sleds.
When they arrived at the finish line at the Hercules Inlet on January 21, they became the first all-female group to complete such a crossing.
After comparing physiological markers taken one and two months prior to the expedition to those taken 4 to 16 days after it ended, Dr Gifford and his colleagues were surprised to observe that the women’s sex steroids, corticosteroids, and metabolic markers were largely unaffected by the rigorous activity. Only levels of leptin – a hormone involved in fat storage and metabolism – and vitamin D were significantly altered, appearing to fall during the trek but recovering by day 11 afterward.
Markers for bone cell turnover were found to be in flux before (likely due to the intensive training) and immediately after the journey, but these factors also returned to normal levels by day 11. Bone strength and integrity were unchanged.
And quite remarkably, even though hair samples showed that monthly average cortisol was elevated during the emotionally and physically taxing journey, the body’s reactivity to the hormone did not change, as it often does as a result of acute or chronic stress.
Less surprisingly, the Ice Maidens lost an average of 9.5 kilograms (21 pounds) of fat mass; their lean mass was unchanged.
Overall, these changes are similar to what one would see in a team of male athletes.
“This study is unprecedented in women, demonstrating marked resilience in reproductive function, the HPA axis [the hypothalamic-pituitary-adrenal neuroendocrine system], and bone, suggesting that female biological capacity for extreme endurance exercise is greater than anticipated,” the researchers wrote in their study abstract.
Because these results came from a small group of Caucasian women, it would be beneficial to confirm women’s exercise resilience in larger, more racially diverse cohorts. But seeing as physical challenges as hardcore as crossing Antarctica on skis only appeal to a small number of humans of any type, it might take a while to do so.
Meanwhile, the researchers plan to look into how different extreme activities negatively impact health, with the aim of revealing ways of preventing such outcomes.