The human body perspires after exposure to high temperatures, with exercise, in response to strong emotions and as a response to certain foods. Perspiration is primarily a function of the body’s need to cool itself. When environmental temperatures rise above the body’s resting temperature -- generally 98.6 degrees Fahrenheit -- temperature receptors on the skin alert the brain to begin the sweating process. Several factors may influence the color of your perspiration.
Bacterial Sweat Stains
In most cases, yellow sweat is not really yellow. Rather, sweat is clear when it leaves the body. When sweat reaches the skin’s surface, bacteria that live on the skin metabolize the fats and oils in the sweat and produce the odor associated with sweat and the colored liquid that transfers to clothing, causing sweat stains. Using a semi-soft antiperspirant, applying it to dry skin and allowing it to dry before dressing may reduce these stains.
Chromhidrosis is a rare condition that a causes perspiration to be colored. The affected sweat glands are primarily located in the underarms. These glands do not become functional until a person reaches puberty. In rare cases, a yellow-brown, finely granular pigment mixes with sweat and sweat appears colored.
Pseudochromhidrosis is a variation of chromhidrosis. This condition occurs when colorless sweat reaches the skin and mixes with agents such as bacterial byproducts, dyes, chemicals and pigments. If the colorant is yellow, sweat will appear yellow. Identifying the colorant and avoiding it will prevent this from occurring. Pseudochromhidrosis caused by bacteria can be treated with antibiotics.