In a previous blog post, we talked about what sweat is and where it comes from, but why is it that we sweat in the first place?...
In a previous blog post (see: Know Sweat), we talked about what sweat is and where it comes from, but why is it that we sweat in the first place?
The primary function of sweat is to cool the body when it begins to overheat. This thermoregulatory role is completed by both types of sweat glands, but much of it is taken care of by the eccrine glands found all over the body (particularly on our hands and soles of the feet). As the water in your sweat evaporates into the air, it takes with it some of the heat the body is producing and thus helps maintain a safe temperature. But why produce sweat that causes odor?
Perhaps in the name of safety.
One of the major theories as to why our sweat smells is that apocrine sweat contains pheromones, chemical molecules that cause behavioral or hormonal changes in another member of the same species. A study found that people can detect alarm scents in the body odor of others, communicating fear and anxiety to those around them. Evolutionarily, nervous sweats could have served as a warning signal to others (now, however, job interview-driven-pit-stains may not send the signal we want them to).
Another study found that individuals can recognize the odors of their kin but cannot recognize stepsiblings or spouses, suggesting that odor could play a role in family relations1. This could historically have been a tool to avoid incest and seek out familiar individuals. Other interesting consequences of sweat-produced pheromones include a newborn's ability to find his mother's breast using the odor released from apocrine glands in the nipple, and the synchronization of women's cycles when living in close quarters.
Perhaps, also, we sweat in the name of love.
Many of the pheromones in our sweat that have been researched thus far have been found to play a role in who we are attracted to, when, and why. One study found that sniffing a particular male pheromone lead to improved mood and sexual arousal in young women2. Furthermore, women have been found to prefer the scent of men with immune systems most different than their own, an adaption that would allow for better defenses against disease in their children.
Men's sexual interest has also been shown to be impacted by scent. In one study, men consistently considered a woman more attractive when in the fertile portion of her cycle. In another, men found the woman's body odor more attractive when she was ovulating and responded with higher levels of testosterone. Who knew sweat was sexy? Perhaps, if we are looking for a mate, we have another reason to put the antiperspirants aside.
I think it is time to Rethink Sweat. It seems as if sweat may, subliminally, be doing more for us than we know. Instead of trying to disconnect from our sweat, perhaps we should embrace it, embrace it in all its sweaty glory.
1 Porter, et al. Odor signatures recognition. Physiol Behav. 1985 Mar;34(3):445-8.
2 Verhaeghe, et al. Pheromones and their effect on women's mood and sexuality. Facts Views Vis Obgyn. 2013; 5(3): 189-195.