At age 14, Kiera Habenick's body was telling a story that researchers at the University of Southampton had never fully documented before: the moment when a girl's sweat glands begin to reorganize their entire strategy. Pedaling through 36°C heat for 40 minutes in the university's climate chamber, wearing absorbent patches that would map her perspiration, she was helping to solve a puzzle that has implications for everything from teenage sports participation to public health messaging about heat vulnerability.
Until now, researchers knew that children sweat differently from adults, but the specifics remained murky. The study, led by Dr. Hannah Blount, a postgraduate researcher in thermal physiology, followed 28 girls aged 8 to 25 through controlled exercise sessions, tracking exactly where and how much they sweated. The findings reveal a decisive turning point: age 14 marks the moment when girls' sweating patterns shift fundamentally toward the adult distribution, with a marked increase in sweat production from the torso—chest, abdomen, and back—rather than concentrating on the hands and feet, where younger children primarily cool themselves.
"We found that at the age of 14, girls begin to sweat across their torso more than from the extremities of hands and feet," Dr. Blount explained. The increase in sweat across the torso rises linearly with age, likely driven by higher sweat output per gland. The discovery matters immediately in one practical way: it reveals what sportswear designers have been missing. Until girls reach this pivotal age, they need different cooling strategies. By 14, however, moisture-wicking fabrics on sport tops become essential, along with more ventilated designs that allow sweat to evaporate effectively from the core.
This physiological finding arrives at a critical moment. Girls in their teenage years experience a well-documented dropout from sports—a pattern that barriers to comfort and performance only worsen. By understanding exactly when and where girls' bodies change their cooling mechanisms, designers can build better sportswear that keeps teenage girls comfortable enough to stay engaged. "Anything we can do to help reduce the barriers to participation in sport for girls and women of all ages in a warming climate is a positive," Dr. Blount said.
The research also reshapes how we think about vulnerability to heat stress. Traditional public health messaging assumes children are universally more at risk because they sweat less and cannot cool down as efficiently. But Professor Davide Filingeri, co-author and Professor of Human Thermal Physiology, points out the reality is more nuanced: "This research has demonstrated there are parts of children's bodies that sweat less, but also parts that sweat more." The finding adds precision to our understanding of who faces genuine heat vulnerability and why—information that becomes increasingly urgent as global temperatures rise.
The teenage participants themselves recognized the significance of their contribution. Kiera, 13, reflected on the experience: "It felt surreal that my results would contribute to something so important, but that made it exciting that I was helping with something meaningful—even though I was just cycling." Beatrice Filingeri, 9, captured the spirit more simply: "It was a sweaty experiment but real fun to do!" The research, published in Experimental Physiology, opens a new chapter in understanding how girls' bodies mature—and how that knowledge can keep them cooler, more comfortable, and more likely to embrace sport during the crucial teenage years.