A new study shows that when women exercise, their body processes oxygen a lot faster than men's. This indicates superior aerobic fitness, explain the researchers. In other words, women may be naturally fitter than men.
As society is making more and more progress in the sociopolitical realm of gender equality, there are fields where, in addition to equality and fairness, physical differences between the sexes matter a great deal. Athletic training is one such field.
But new research challenges the traditional belief that men are athletically superior to women. In fact, by measuring women's response to aerobic training, a new study suggests that the opposite may be true.
The new study examined sex differences in the body's response to aerobic fitness; more specifically, it focused on how sex affects the body's ability to process oxygen once it starts to exercise.
Thomas Beltrame, from the University of Waterloo in Canada, led the research, and the findings were published in the journal Applied Physiology, Nutrition, and Metabolism.
Women outperformed men by 30 percent
As Beltrame and colleagues explain in their paper, the previous studies that have decreed men are capable of faster oxygen intake — a standard measure of fitness — than women were conducted in children and older adults.
However, the matter had not been investigated in healthy young adults. So, the researchers hypothesized that in this population sample, too, the findings of previous research would hold true — men would have a faster oxygen turnover.
Beltrame and team set out to test out their hypothesis. They recruited 18 healthy young participants; nine of them were male, nine female. All participants were highly active, with similar ages, weight, and levels of aerobic fitness.
Participants were asked to engage in an "incremental cardiopulmonary treadmill exercise test," as well as in three treadmill exercise tests of moderate intensity.
The tests revealed that "the peripheral and pulmonary oxygen extraction dynamics were remarkably faster in women." More specifically, women circulated oxygen in their body 30 percent faster than men, on a constant basis.
In other words, women may be naturally more athletic. The hypothesis was disproven.
Findings may change athletic training
Richard Hughson, a professor in the Faculty of Applied Health Sciences at Waterloo and a corresponding author of the study, explains the meaning of the test results.
"We found that women's muscles extract oxygen from the blood faster, which, scientifically speaking, indicates a superior aerobic system," he says.
Oxygen uptake is a standard measure of aerobic fitness, and it describes the amount of oxygen that the body can take in and use per minute.
As the American College of Sports Medicine explain, our oxygen consumption rate "provides a measure of the maximal ability to perform high-intensity aerobic work, [and] is strongly associated with performance and health."
Therefore, a higher rate of oxygen processing means that women may be less prone to muscle fatigue and more likely to perform better athletically. They may also be more resilient, as higher oxygen processing also indicates a lower perception of physical effort.
"The findings are contrary to the popular assumption that men's bodies are more naturally athletic," Beltrame says.
"While we don't know why women have faster oxygen uptake, this study shakes up conventional wisdom [...] It could change the way we approach assessment and athletic training down the road."