Are Cotton T-Shirts Good for Workouts?

YOU’VE GOT A stack of cotton t-shirts in your closet that you can toss on any time. But given all the performance shirt options out there, it’s fair to wonder if your favorite comfortable cotton t-shirt is the best choice of apparel for a hard session at the gym. Are cotton t-shirts good for workouts or should you invest in performance gear when it comes to exercising?

While cotton feels good against your skin under everyday circumstances, things can get dicey when you wear this fabric during a workout. That’s not true of all workouts, making the decision of whether to toss on a cotton t-shirt before heading to the gym one that requires some follow-up questions.

Here’s what trainers and a textiles expert want you to keep in mind before dipping into your cotton t-shirt stash for your next trip to the gym.

Are Cotton T-Shirts Good for Workouts?

It depends a lot on how much you plan to sweat. “Because cotton is a hydrophilic fiber, it readily absorbs sweat and other moisture,” says Imran Islam, Ph.D., associate professor of textile development and marketing at FIT. “As the fibers absorb water, they swell, which reduces fabric porosity and airflow.”

Over time, that once-breathable fabric ends up clinging to your skin and trapping in heat, leaving you feeling hot, Islam says. That’s why he recommends using a shirt made from performance fabric instead.

How a Cotton T-Shirt May Impact Performance

It’s a stretch to say that wearing a cotton t-shirt will wreck your workout, but it could make you feel less comfortable while you grind it out. “The feeling of a heavy, soaking-wet shirt is distracting,” says Dani Singer, CPT, from Fit2Go. “Since the sweat is trapped, it limits the body's natural cooling, increasing the risk of overheating and chafing.”

Albert Matheny, CPT, from Soho Strength Lab, calls a wet, heavy t-shirt “annoying” while you’re working out. “If you’re doing some kind of movement and the shirt gets wet and heavy…that’s not fun,” he says. “If you’re someone who sweats a lot, what are you doing wearing a cotton t-shirt?”

That’s where performance shirts come into play. “Performance fabrics are engineered with fibers that wick moisture rather than simply absorb it,” Islam says. “Instead of soaking up sweat, they transport it from the inner surface of the fabric to the outer surface, where it can evaporate quickly.” This helps the shirt stay breathable, dry faster, and you feeling cooler, Islam says. “In a nutshell, for workouts or competitive sports, you want fibers with strong wicking performance, not high absorbency,” he says.

You Might Smell Better in a Performance Shirt, Too

If you don’t mind your shirt sticking to your body, more power to you. But you might not enjoy the odor that can build up in cotton shirts over time when they’re your preferred workout top. Cotton has a standard moisture content of about 8.5% by weight, so 100 ounces of cotton contains about 8.5 ounces of water, Islam says. “This inherent moisture and its cellulose structure support additional dampness and microbial activity inside the fibers, which can eventually lead to odor formation,” he says.

But performance fabrics are usually made from synthetic fibers that hold very little internal moisture. “Because these fibers contain only a negligible amount of water within their structure, they provide a much less favorable environment for microbial growth and odor formation,” Islam says.

There Are Some Situations Where a Cotton T-Shirt Is a Solid Choice

If you’re planning to do low-intensity activities where you won’t break a heavy sweat, like yoga, walking, or stretching, Singer says that a cotton T-shirt is fine. “Cotton and linen are ideal for light workouts, as long as your sweat rate does not exceed how quickly the fabric can dry,” Islam says.

When it comes to choosing the right shirt for your activity, it’s really best to try to gauge in advance how hard you plan to go. “Base your decision on sweating,” Matheny says.