'How your bra size is linked to how much you sweat'

Would you believe your bra size determines how much you sweat? Yes, honestly – is indicative of breast size and that’s responsible for sweat production across the breast during physical activities.

A study by has revealed a surprising link between breast size and the amount of sweat breasts produce during exercise.

Sweat production is primarily influenced by factors such as body size, metabolism, and environmental conditions – however, the research team estimated that breast size could also impact the amount you sweat.

The study looked at 22 women of different ages and breast sizes while they ran in a warm climatic chamber.

They measured how much sweat they produced across the breast, how much heat their bodies were producing and how many sweat glands they had on different parts of their breasts.

The research, conducted by postgraduate researcher Hannah Blount at the University’s ThermosenseLab says: “Our thought process was to look at how sports bras offer support and comfort to women of varying breast sizes, especially in hot conditions, when they are more likely to experience issues like chafing and significant sweat accumulation in the ”.

Hannah found that bigger breasts have fewer glands, meaning they produce less sweat when working out.

“Here we got the most exciting finding, as our results indicated that larger-breasted women presented fewer sweat glands, and so they produced less sweat across their breast, she says. “This fundamental knowledge is something we can now use to inform sportswear design that considers the needs of women of varying breast sizes.”

The experiments were conducted in the state-of-the-art climate chamber of the ThermosenseLab housed in the Southampton Clinical Research Facility. Women were asked to jog for 45 minutes in 32C heat while their breast sweat output was monitored.

The lab’s 3D scanning calculated breast surface area, while sweat gland density was measured using iodine-infused paper which, when placed on sweaty skin, changes colour.

Dr Davide Filingeri, Associate Professor in Thermal Physiology at Southampton University, said: “Women are a group of individuals who undergo unique anatomical, physiological and hormonal changes across their lifespan. Consider the impact of the menstrual cycle, pregnancy and menopause, all of which impact a woman’s heat tolerance, thermal sensitivity and comfort. As such, Hannah’s research … has the potential to inform person-centred innovation in sportswear, which will ultimately help women thrive in our warming climate.”

Hannah added: “We’re becoming more sedentary as a society, so if we can do anything to aid women to become more active while making sport more accessible, then that’s really exciting.” You bet.