If you leave the sweat in your hair to dry after your workout, this is where damage can occur. Sweat can dry on your scalp and potentially clog your hair follicles, as it can mix with bacteria and irritate or damage your scalp. The high salt content can also impact your hair colour if it's been dyed.
Good news: for most people, it's okay to skip washing your hair after a workout, even if you worked up a sweat. How often you need to wash your hair ultimately depends on your hair type, texture and personal preference. Thin, fine hair typically requires more frequent washing than thick, coarse hair.
Does Sweating Cause Hair Loss? Without proper care and cleaning of your hair and scalp, sweat can lead to hair loss by clogging hair follicles and disrupting hair growth. Sweating is a part of the body's natural mechanisms and serves an important purpose in regulating body temperature.
Though sleeping with wet hair won't give you a cold, Dr. Shah says that it does increase your risk of developing a fungal infection of the scalp. Fungi, such as Malassezia, can lead to conditions like dandruff or dermatitis, according to Shah, who recommends going to sleep with dry hair when possible.
Healthy Hair Growth
Researchers agree that too much sweat can be dangerous, but the same study suggests that sweating promotes hair growth. After a heavy workout, your body will sweat a lot, and this helps unclog the hair follicles. What this means is that there will be more space for new hair to grow.
Sleeping with wet hair can lead to a host of problems for the scalp: unwanted bacteria, fungal infections, skin irritation, itchiness, dryness, redness, and dandruff," says hairstylist Miko Branch, co-founder of hair care brand Miss Jessie's Original.
Use dry shampoo before your workout.
Instead, mist the product throughout your roots before you hit the gym. That way the formula can soak up excess oils and debris while you sweat. Try it: (L to R) Amika Perk Up Dry Shampoo, $22; sephora.com. Moroccanoil Dry Shampoo Dark Tones, $26; sephora.com.
"Sweat glands secretion are mixed with bacteria if not washed, it can lead to formation of fungal infections," says stylist Kristine Cruz, who does recommend a wash after some excessive sweating. And with that, my sweaty—but not dirty!
"The hair and scalp end up smelling because there's a build-up of sebum and sweat, and it makes it a breeding ground for yeast, dead skin cells, and bacteria," dermatologist Francesca Fusco, MD, says.
Sweat Can Clog Up Your Hair Follicles
But the reality is that when sebum and a buildup of sweat combine, that can create a substance that ends up clogging up your hair follicles. And yes, over time, that can result in hair loss if you're not careful.
Sweating from your scalp helps unclog your hair follicles, allowing room for new hair growth. It also opens up the pores on your scalp, releasing any buildup inside your pores that could be stunting the growth of your hair.
Apply Baking Soda to the Scalp: Baking soda is a powerful antidote for smelly hair, as it absorbs all the bad odours and excess oil from your hair and scalp. Prepare a paste by mixing one part of baking soda and three parts of water. Apply this paste to your damp hair and rinse it off after 5 minutes.
If your hair smells bad within a few hours of washing well, you might be having 'smelly hair syndrome'. This is a condition that leaves a terrible odor from the scalp. The smell is so strong that you can't help but notice. Medicated shampoos and anti-fungal hair care products can help.
The buildup of sebum, dead skin cells, sweat, and product residues marinate your roots, making it the ideal environment for bacteria to proliferate. But over-washing isn't the cure to eliminating smelly hair. Shampooing your mane too often can strip the natural oils from your strands, causing them to dry out.
Sweat is the body's way of naturally cooling you down and eliminate toxins. But despite being a natural process, sweat can also bring damage to the hair. Due to the salt content of the sweat, letting it sit in your curls for awhile will definitely cause some dryness in your strands and scalp.
Your hair could smell nasty or stop growing
Hair traps moisture, Lamb said, meaning that built-up bacteria on unwashed scalps can start to pick up a mildewy or sour smell after several days or a week, especially if exercise is involved.
Rossi generally tells his patients they should wash their hair once or twice per week. But if you've had chemical treatments that can make your hair drier — such as bleach, perms or relaxers — you might want to wash it less than once weekly to avoid breaking or brittle hair or split ends, he said.
Typically, there should be no fragrance at all. However, if you smell something unusual, pungent, or bad on your fingertips after brushing your hair, this implies you have a smelly scalp and hair.
According to Redway, if you're doing heavy cardio daily, you should wash your hair two to three times a week. “Rinsing your scalp in between shampoos will help clean it. And if you have curly or textured hair, co-wash [with conditioner but not shampoo] in between.
Many beauty experts say that it's okay to skip your hair washing after a workout. Rinsing with water may be enough. In addition to saving time, skipping your post-workout hair washing every once in a while can actually be beneficial for your scalp health.
“While it isn't recommended to wash your hair every day after a workout to avoid frizz and dryness, it is important to maintain hygiene as unwashed hair can be a source of bacteria and fungi,” says Dr Deshmukh. She also suggests using a separate towel or tissues to dab the sweat off your scalp.
Water is effective at washing away dirt, dust, and other water-soluble debris from the hair and scalp without stripping the hair of this sebum. However, Mamelak notes that if there are other oils in the hair (from a haircare or styling product, for example), a good portion of these will be left behind as well.