Shaving the arms, legs, back, and pretty much any other portion of the body exposed to the water has been shown to minimize frictional drag, enhance streamline, and increase the swimmer's awareness and feel for the water (more on that in a second). Shaving is also fairly popular among bikers and triathletes. The science behind why shaving before a swim reduces drag is simple: The less skin that comes in contact with the water, the less resistance there is to moving through the water. Of course, you still need to be able to breathe underwater but this is true for anyone who doesn't have flippers or a fish tail. One study showed that men who shaved their legs reduced their drag by about 15 percent and women by about 10 percent. There are several reasons why shaving might improve your swimming performance, including: 1 It makes you more aware of your environment. When you shave, you're removing the hair cells that collect information about pressure changes, temperature variations, and other factors that go into determining how fast you swim. By reducing the amount of information you receive from your senses, shaving leaves you feeling like you need to rely even more heavily on math and data to determine what's going on around you. This might make you a better swimmer since you'll have to think harder while you're in the pool. 2 It makes you use different muscles.