No matter what sport you play, exercising in the sun can be extremely dehydrating, Maharam says. "Make sure that you are well hydrated with water or a sports drink like Gatorade, because as you sweat, you can lose a lot of salt, which speeds the dehydration process," he says.
Particularly dangerous can be drinking beer or other alcoholic beverages while playing sports in the sun, Maharam says. Alcoholic drinks are diuretics, meaning that they encourage the loss of fluid. "So water or Gatorade is a better hydration solution," he says. "You don't realize how drunk you are getting in the sun because you are drinking the beer to quench your thirst," he says.
Besides adequate hydration, another universal precaution is the use of sunscreen, says Bruce Katz, MD, director of the JUVA Skin and Laser Center in New York City and an associate clinical professor of dermatology at Columbia University College of Physicians and Surgeons, also in New York.
"People who play sports on the beach are in the sun, even though they are not actively trying to get tan," Katz tells WebMD. "They are getting as much sun as people who are tanning because they are getting sun exposure from above and sun exposure from below because the sun reflects off of the sand."
Katz recommends applying a sunscreen with an SPF (sun protection factor) of at least 15. "Don't rely on waterproof claims," Katz says. "As a rule of thumb, if you perspire heavily or swim a lot, reapply sunscreen every 40 minutes. And, sunscreen should contain either zinc oxide, titanium dioxide, or parsol because these blockers block out both UVA and UVB rays."
Finally, swimming is probably one of the most popular summertime sports -- especially in the ocean. To prevent drowning, the United States Lifesaving Association suggests that swimmers always swim near a lifeguard, never swim alone, don't fight the current, and swim sober.