When you think of keeping cool, chances are you’re thinking of short sleeved shirts, but if you choose the right long sleeve base layer, that might be a mistake. Is it actually possible that long sleeve shirts might, despite how counter intuitive it sounds, be better for keeping you cool than short sleeve shirts? The answer is yes, albeit a qualified yes.

If you are wearing a cotton Long Sleeve T-Shirt , then a typical cotton tee shirt is going to serve you better for keeping you cool. But in this case, you’re really looking at the lesser of two evils, because neither one is really ideal for regulating body temperature, especially when you’re active.

Cotton is a popular fabric. Partly because, under normal conditions, it breathes well and is comfortable on the skin, and partly because it’s easy and cheap to grow. Cotton, from the point of view of the athlete or, really, anyone who does hard work in it, is that it absorbs water. This is a good quality in a towel, but a bad one in a shirt.

The reason this is bad is because the human body is designed around using water to maintain our body temperature.

When you start getting too hot internally, you sweat, and the sweat carries heat away with it. If you’re not wearing any clothes, this tends to work perfectly well.

If on the other hand you are wearing a shirt made of regular material, usually cotton but this applies to a lesser extent to wool or silk, then the shirt absorbs the water. This, in turn, prevents you from lowering your body temperature, which leads to even more sweat.

This has the dual effects of making you uncomfortable and reducing your ability to do what it is you want to do. If your body builds up too much heat, you will pass out or, in extreme cases, die, so it generally prevents this by slowing you down when it gets too hot. This is good for your health, but less than ideal otherwise.

A good long sleeve base layer or, really, any kind of base layer, will go a long way towards helping the situation.

The idea behind a base layer is to have clothing that is designed to support what your body wants to do rather than work against it. In this case, that means wicking water away from you.

Basically, the fabric in a good long sleeve base layer sucks the sweat away from you and into the air. This allows you to regulate your body temperature better, meaning you play better, and it stops your clothes from sticking to you, which is probably reason enough to do it.