Why do sprinters wear sunglasses?

[Lone Star]

I have found that most sprinters on tv usually wear sunglasses. Why? Do they just want themselves to look cool? Or sunglasses have other functions for them?

[Wyaconda]

Wearing sunglasses can benefit the sprinters much. It is well known that sunglasses have the function of protecting eyes by blocking UV and UVB. They can effectively reduce glare that will make eyes uncomfortable and let people see more clearly. When sprinters are doing sports in sunny days, they tend to spend a long time in the sunlight. This poses great threat to their eye health. So, they need sunglasses to shield their eyes from harmful sunlight. Sunglasses will also give them an improved vision so that they can see the track clearly. Some sprinters race at night in a stadium. At this time, the stadium will full of intense artificial lights such as stadium lights and camera flashes that will affect the performance of sprinters. The sunglasses can help to block the lights for them.

[Lonetree]

Sprinters wear the sunglasses not only for the purpose of looking cool. This is because that the sprinters require much focused attention when they are running. However, there are many reflection light and refraction light in the field especially when the games are held in the outdoors. Therefore, in order to screen off the annoying light and prevent the light from making the sprinters bad performance, the sprinters usually wear sunglasses. Besides, on sunny days, there are many ultraviolet rays in the sunshine, and wearing sunglasses can well protect the eyes of the sprinters.