As children, most of us heard lots of health advice. Unfortunately, some of it, however well-intentioned, was medically incorrect. See if you've ever heard -- or believed -- any of these common summer health myths.

False: Wait a half hour after eating before you can safely go swimming

This one seemed almost universally accepted when I was a child and is still believed today. The myth involves the possibility of suffering severe muscle cramping and drowning from swimming on a full stomach. While it's true that the digestive process does divert the circulation of the blood toward the gut and to a certain extent, away from the muscles, the fact is that an episode of drowning caused by swimming on a full stomach has never been documented. Neither the American Academy of Pediatrics nor the American Red Cross makes any specific recommendations about waiting any amount of time after eating before taking a swim. There's a theoretical possibility that one could develop a cramp while swimming with a full stomach, but a person swimming in a pool or controlled swimming area could easily exit the water if this happens. As with any exercise after eating, swimming right after a big meal might be uncomfortable, but it won't cause you to drown.

False: Sunburn will fade into a tan

"You need to burn first before you start to tan," is another old saying that isn't true. Sunburn is a burn and not a prerequisite stage for a tan. Sunburn will result in skin damage, redness, and eventual peeling. Any amount of prolonged sun exposure poses a risk of sunburn and may increase your risk for skin cancer.

False: Dark-skinned people don't need sunscreen

People with lighter skin have less melanin, the pigment that absorbs UV radiation and protects skin, than darker-skinned people. While light-skinned people will be very sensitive to the effects of UV rays from the sun, those with darker skin can still be affected by damaging UV radiation. The American Academy of Dermatology recommends everyone use sunscreen with broad-spectrum protection, and SPF of 30 or greater, and that the sunscreen be waterproof.

False: Watermelon seeds will germinate in your stomach if swallowed

Finally, there's the watermelon-seed myth. No, the seeds won't germinate and grow in your stomach if you swallow them. There is a very small risk of damage to the intestine (inflammation, obstruction, or a wound or tear in the bowel) from swallowing any small, sharp object such as a seed. A watermelon or other type of seed could potentially lodge inside the appendix and lead to appendicitis, but this is very unlikely to happen. The benefits of including fruit in your diet far outweigh any risks associated with swallowing seeds.

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