There’s a reason why you should never let ’em see — or smell — you sweat. You appear not just less confident, but less competent and less trustworthy as well.
It’s not exactly a revelation, but it is sobering — women are judged differently based on their sweat, according to a new study published in PLOS ONE. Experts in the field of perspiration have broken sweat down into three types: sweat from exercise, sweat in response to heat, and sweat from stress. Each is driven by a slightly different body process — exercise and heat sweat come from the body’s eccrine glands, which pump out clear, odorless water on the surface of the skin that is tinged with a bit of salt (these are the glands responsible for damp foreheads and clammy palms and feet). Stress sweat, however, comes from the more hirsute regions of the body — think scalp, armpits and groin — and is saturated with fats. Those aren’t odoriferous per se, but they serve as food for the bacteria that blanket the skin, and it’s those bugs that emit the hallmark BO signalling sweat under pressure.
And according to scientists from Monell Chemical Senses Center, that odor also affects how people perceive the sweatee. While previous work suggested that people changed their emotional reactions toward others based on their odor, the latest study found that people may also judge others on their compatibility and trustworthiness according to their scent.
The researchers asked 44 female participants to provide samples of underarm sweat at the start of the study, and under three different conditions — after exercising on a stationary bike for 15 minutes, after stressful events that the scientists created, and after the same stressful events but treated with an antiperspirant. The anxiety-producing exercises included preparing a speech for five minutes, doing mental math problems for five minutes, and five minutes of public speaking. Secret provided its Clinical Strength antiperspirant and funded the study, but did not influence its design or data, according to the scientific team.
The researchers then asked 120 male and female volunteers to smell the various sweat samples while watching videos of the women who provided the samples as they went about their daily duties at home, in the office or in a childcare setting. The evaluators rated the women they saw on how stressed or confident they appeared. Those who smelled samples of untreated stress sweat were significantly more likely to say the women to whom the samples belonged were more stressed than those who smelled the treated sweat. What’s more, men were more likely to see the stress-sweating women as less confident, trustworthy and competent when they were asked about those characteristics.
Although the researchers only looked at women for this study, the authors say that prior research showed that inhaling the body odors from men under stress also induced anxiety in female subjects.
The scientists say this is the first study to link sweat odor to social perceptions, so it’s too early to say whether perspiration odor in all societies would have the same effect on trust and competence measures. The American culture places a premium on smelling fresh and on masking body odors, but other societies may not place as much value on hiding natural emanations. So in the U.S., the results could be a boon not just for deodorant and antiperspirant manufacturers, but for video conferencing ventures as well. The next time you’re nervous about a speech or a presentation, you might consider finding ways to not let them smell you sweat.