Technical T-shirt or cotton: which is better for working out?

If you really sweat during your workout, a well-made polyester technical T-shirt is usually the better choice: it absorbs hardly any water and feels dry again sooner. Cotton is pleasantly soft, but it soaks up sweat and stays wet for a long time. Cotton is fine for calm sessions and everyday wear; for classes, strength training in a warm gym or indoor sports, polyester or a blend is the better choice.

Why does a cotton T-shirt feel wet when you exercise?

Because cotton holds water. Öko-Test (a German consumer magazine, in German) says the fibre can absorb up to 65 per cent of its own weight in water and describes exactly that as a drawback in clothing: moisture from sweat or rain is released only slowly. The shirt gets heavier, clings to the skin and cools you down during breaks.

According to the same source, polyester textiles absorb hardly any moisture and move sweat on quickly. How well that works in the finished shirt, however, does not depend on polyester alone but on the fibre shape, the knit and the finish of the fabric. The sweat spreads across the surface of the fabric and evaporates there. That is why a thin technical T-shirt often dries on the hanger within a few hours after training, while a thick cotton T-shirt does not.

When is a technical T-shirt the right choice?

Whenever you sweat for a long time: in a fitness class, during circuit training, in a sports hall or when you train at the gym for more than an hour. Look for light fabrics and open mesh zones where the heat builds up.

The Nike Pro top is made of 100 % polyester with mesh panels on the back and sides. The PUMA Train Favorite tank, made of recycled polyester and elastane (spandex), has mesh panels, a racerback cut and flatlock seams against chafing. For women, the Erima Celebrate 125 technical T-shirt is made of a light, quick-drying box-mesh fabric.

What can cotton-polyester blends do?

Blends are a compromise: the cotton gives the soft feel, the polyester makes the fabric dry faster and keep its shape better. The higher the polyester share, the closer the shirt comes to a pure technical T-shirt. Blends suit anyone looking for a T-shirt for the gym and for everyday wear afterwards.

The Nike Dri-FIT Fitness T-shirt is a little over half cotton; the rest is polyester with Dri-FIT technology. The Under Armour B Logo Wordmark T-shirt is 60 % cotton and 40 % polyester. The Jako Iconic T-shirt is made of a cotton-polyester blend that Jako describes as soft and hard-wearing.

When does cotton still make sense?

When you hardly sweat, change your T-shirt straight after training or like the relaxed drape of a heavy cotton T-shirt. For stretching, mobility exercises at home or as a layer over a technical top on the way to the gym, there is nothing wrong with pure cotton. In the weights room, too, many people deliberately wear loose cotton T-shirts.

The Nike NAC T-shirt is made of 100 % midweight cotton with a loose cut and dropped shoulders. The adidas Copa Sign T-shirt is also 100 % cotton, in single jersey with a regular fit.

Are there alternatives to polyester and cotton?

Yes, above all blends with merino wool. They are used more for outdoor sport in the cold season than in a warm gym. The Craft Core Wool Merino set, for example, is a base layer set made of a merino wool and polyester blend that Craft describes as soft and designed to keep you dry and warm all day. For the trip to training in an Eifel winter or for sessions in an unheated room, a base layer like this under your training T-shirt is worth considering. In a warm studio room it is too much.

A practical middle way for many people: a technical T-shirt for the session itself and a cotton or blend T-shirt to change into afterwards. That way you stay dry while training and have something soft and fresh on for the journey home.

Does polyester smell faster than cotton?

Many people find that it does. In its care guide, Nike explains that it is not sweat itself that smells, but the bacteria that break it down, and that these collect mainly on the inside of clothing. That leads to practical advice: do not leave a wet T-shirt in your bag after training, hang it up, and turn it inside out before washing. Some brands give their fabrics an odour-control treatment; if so, it is stated in the product description. More on this in how to wash gym clothes.

How can I tell the fabric in a store?

From the sewn-in label: it shows the composition in per cent. Brand names such as Dri-FIT, dryCELL, Climacool or HeatGear tell you that the brand promises moisture-wicking, but not how much cotton is in the fabric. One Nike shirt with Dri-FIT can be more than half cotton, another pure polyester.

• 100 % polyester (often with elastane): quick-drying, for lots of sweat
• Blend with mostly polyester: close to a technical T-shirt, a little softer
• Blend with mostly cotton: soft, good for everyday wear, dries more slowly
• 100 % cotton: soft, absorbent, for calm workouts and everyday wear

The bottom line and checklist

• Lots of sweat, a long session, a warm room: technical T-shirt
• Gym and then into town: blend
• Stretching, gentle exercise, little sweat: cotton is fine
• Change out of a wet T-shirt after training, especially in winter
• Check the composition on the label, not just the brand name

An overview of all the fabrics in gym clothes, from leggings to comfort trousers, is in our guide gym clothes: which fabrics. If you also run outdoors, you will find tips for the cold season in winter running clothes.