Acne's primary cause is the buildup of dead skin cells, skin oil and bacteria in pores. This buildup can be controlled to some extent but not completely stopped. Acne lesions take forms such as blackheads, whiteheads, pustules and papules. Sweating from exercise or any other reason affects these pimples, but not in a positive way. Blackheads can worsen from perspiration without preventive actions.
Blackheads are a mild type of acne lesion, according to the National Institute of Arthritis and Musculoskeletal and Skin Diseases. They develop when your skin oil and dead cells partially block a pore, leaving some space for air to have contact with the blockage. The exposed area turns dark and appears as a black spot on the pimple. A related lesion type, called a whitehead, happens when the pore is blocked completely and no air reaches the material inside of the pimple.
Blackheads and other pimples from sweating happen when the perspiration contributes to pore blockage. Wearing oily makeup compounds the problem, and even oil-free brands contribute to acne if worn during very heavy physical activity, Acne.com warns. Sunscreen also blends with sweat to magnify its pimple-causing effects. Clothes made from fabrics that trap sweat against your skin rather than wicking it away can lead to pimples on your chest, back and other covered areas.
Blackheads usually respond to over-the-counter acne preparations with ingredients such as benzoyl peroxide, sulfur, resorcinol or salicylic acid. These ingredients work in various ways, such as slowing oil production and cell shedding or breaking down blackheads and other pimples. Wear workout clothes that draw moisture away from your body. Prevent sweat-related pimples by showering as soon as possible after you work up a sweat. Medicated cleanser is OK to use in the shower, but do not scrub your skin roughly. You may irritate the blackheads and other pimples and make them even worse.
Exercise-induced sweat and perspiration from other causes may lead to a certain type of acne called pityrosporum folliculitis, according to dermatologist Dr. Cynthia Bailey. These pimples have a different appearance than blackheads, as they usually manifest themselves in white or red bumps. This acne type is common in youngsters who train hard for sports because of the excess sweat caused by their physical activity. The pimples tend to show up in the hairline, on the forehead, jaw, backs and sides of the neck and the upper back and chest. Like blackheads, they are treatable with mild washing and cleansing, although severe cases need medication. Yeast plays a role in these pimples, so your doctor may give you anti-fungal medication.