baby blue polo shirt Exercise and smelly clothes
Why do some people smell bad after exercise? To start with, freshly secreted sweat has little odor. This is because the long chain fatty acids the axillaries secrete are too big to be volatile. However, smells arise once bacteria break these down. The bacterial by products, together with hormones and sulfur compounds, result in odoriferous molecules (or the post exercise stink).
Sweat is produced by two different types of glands: eccrine and apocrine. Eccrine glands secrete sweat to cool down the body. This sweat is mostly made up of water and salt. Apocrine glands activate when people are stressed (physically or emotionally). These glands they produce a sweat rich with proteins and fatty acids, including a carbohydrate called sialomucin. Sialomucin is a glycoprotein, a protein that has a sugar coating, and the one which bacteria breakdown and this chemical process produces the “sweat odor”.
There is, however, another variable: the type of clothes that the exercising person is wearing. And here there is a big difference: polyester clothes smell worse than cotton at the end of a workout.
To show this, researchers collected t shirts from 26 healthy individuals following an intensive, hour long bicycle spinning session. The scientists then incubated the shirts for 28 hours before having them inspected by a trained odor panel. The polyester clothes were considerably “smellier” than the cotton ones.
The researchers additionally investigated the types of bacteria found on the shirts. The main types of bacteria were the micrococci. There are three common types of bacteria found on the skin: Micrococcus species, Staphylococcus species and Corynebacterium species. Corynebacteria, although responsible for smelly armpits with those who shy away from using deodorant, do not grow well on fabrics.
With the other two bacterial geneses, while Staphylococci do not often produce odors when breaking down human body molecules, the Micrococci are types of bacteria that are adept at breaking down sweat molecules to produce “smells”. In particular, the species M. luteus on human skin transforms compounds in sweat into compounds with an unpleasant odor.
The research also showed that the Micrococci are able to grow much better on polyester than they are on cotton, which further accounts for the polyester gym wear being of a higher odor value. The finding not only covers gym wear. For those who suffer with bad body odor, they may find that wearing cotton helps to reduce the bad smells through keeping the odor producing micrococci at bay.
The findings have been published in the journal Applied and Environmental Microbiology. The research is titled “Microbial odor profile of polyester and cotton clothes after a fitness session”.