by John Stanton
When shopping for running gear, you’ve likely seen or heard about “moisture wicking” as a desirable feature. But what does that term really mean, and will wearing this type of clothing actually help your training? Don’t sweat it—we’ve got a quick lesson for you about this impressive textile technology.
Moisture wicking fabrics like Dri-FIT and CoolMax are made from polyester (a synthetic material) as opposed to cotton (which is derived from a natural source, the cotton plant). Interestingly, the moisture wicking action of technical fabrics mimics a process seen in nature, called “capillary action.”
Capillary action is the ability of a liquid to flow in narrow spaces without the assistance of external forces like gravity. Remember the classic elementary-school science experiment where a stalk of celery is placed in a cup of water mixed with blue food colouring? The liquid is drawn upward through vertical veins in the celery, causing the tips of the leaves to turn blue. It’s a visible demonstration of capillary action, and the same principle applies to moisture wicking fabric.
Technical fabrics can have subtle variations, based on the structure of the yarns used and the treatments applied to them. The main thing to know is that these specialized polyester fibres are “hydrophobic,” meaning they repel water. Their job is to quickly and efficiently move moisture away from its source. So, as the sleeve of a technical tee sits against your skin, droplets of sweat are pulled up through tiny channels in the fabric to the outer surface of the shirt, where they can evaporate more easily.
The net result? Because moisture is transferred away from your skin and evaporates into the surrounding air, your shirt stays dry, and so do you.
In contrast, cotton fabric retains moisture. Cotton will absorb 7% of its weight in water, whereas polyester can only absorb 0.4%. When cotton gets wet, it stays wet, so unless you want to be weighed down by a damp, heavy shirt, skip the cotton tee on your next workout.
There are many benefits to staying dry and comfortable during a walk or run. Sweating is your body’s temperature control mechanism, and by speeding up the evaporation of your sweat, you’re helping cool yourself off. As a result, you are less likely to experience overheating (and its associated complications) while exercising in hot or humid weather.
In addition, if you feel physically comfortable on your run, you will enjoy the experience more—meaning you’ll want to continue with your running routine and cover longer distances. Finally, many races give out a technical t-shirt (usually printed with the event name and date) with your registration package, so you get the added pride and motivation that come with wearing it during your training.
In summary, if the concept of moisture wicking sounds high-tech, that’s because it is. Companies are constantly adapting and innovating their materials to bring you the most breathable and comfortable apparel possible. Now, when you see “moisture wicking” on a product tag, you’ll know what the garment is promising to do.
If you’re going to be spending your time on the roads and trails this summer, you deserve to enjoy the experience rather than be drenched in sweat. Investing in high quality athletic clothing will keep you cooler, drier and happier on the run.
John Stanton is the President and Founder of the Running Room. He is the author of 10 books about running, walking and family fitness.