(Please indulge a brief moment of brotherly bragging: My sister, Ali, is a phenomenal athlete ... the most common cause is drinking too much water, which dilutes the body’s sodium levels.

Do you really need eight glasses of water daily? Learn why hydration needs vary and how to listen to your body for optimal ...

He recommends athletes drink water throughout the day -- rather than too much at once. "Not just scheduled water breaks," Anderson said. "Also, you want to have scheduled water breaks in time off.