Ever hesitated before diving into a pool, trying to remember if it’s been at least 30 minutes since you ate? Health myths buzz around summer pastimes like so many gnats.
“When you’ve heard them from your grandmother and mother…you believe those things.” says Indianapolis pediatrician Rachel C. Vreeman.
Vreeman and fellow Indiana University School of Medicine pediatrician Aaron E. Carroll published studies in 2007 and 2008 debunking medical myths that doctors believe. Among them: Hair and nails continue to grow after a person has died. Reading in dim light ruins your eyesight.
Remembering the many warnings that swimming and outdoor activity inspire, we dug into some of the most pervasive summer health myths.
Myth: Don’t swim for 30 minutes after eating.
If you have a big meal and then go for a swim, the worst thing that could happen is you’d feel uncomfortable or get a cramp, not drown, according to Washington nutritionist Rebecca Scritchfield. (There are no documented cases of drowning or near drowning attributed to eating, according to Vreeman and Carroll.) It’s unlikely that a food-related cramp would disable you, Scritchfield says.
Myth: Swallowing watermelon seeds is bad for you.
Swallowing a few watermelon seeds won’t do any harm, Scritchfield says. Our bodies try to digest them but can’t, so the seeds pass directly through our system. Watermelon seeds are eaten in other parts of the world, such as Nigeria and China, Scritchfield says.
Myth: You can catch poison ivy from someone who has it.
No matter how icky and oozy a poison ivy rash looks, the rash itself is not contagious, Vreeman says. It’s the oil from the poison ivy plant that is contagious, not the reaction to it that is the blistery rash you see on someone’s skin. Poison ivy causes a delayed response; the rash doesn’t appear for 24 to 72 hours after contact with the plant oils. By the time the rash is in full force, it’s unlikely the person would still have the oil on his or her skin. The blisters cannot spread the rash to other people, nor to other parts of the infected person’s body.
Myth: If a jellyfish stings you, urinate on the wound.
That can actually make it worse, said Jennifer Ping, an emergency medicine physician in Honolulu, who has studied the treatments for dealing with jellyfish stings. Jellyfish stings are caused by contact with a jellyfish tentacle, which can trigger millions of stinging cells (nematocytes) to pierce the skin and inject venom, Ping says.
The first line of treatment for jellyfish stings is to get out of the water. Then, remove the tentacles with an object other than your fingers. Deactivate the nematocytes with an acidic compound such as vinegar, either by pouring it directly onto the wound or applying a vinegar-soaked cloth. Once the nematocytes are deactivated, scrape them off with a credit card or other flat object. A paste of vinegar and meat tenderizer also works; scrape it off within 20 minutes or the tenderizer will irritate the skin.
Urine has a different pH than vinegar and, like water, it can cause the nematocytes to swell and release more venom, worsening the sting, Ping says.
Myth: Scratching a bug bite makes it worse.
This one is true. If you scratch a mosquito (or other bug) bite vigorously enough to break the skin, the bacteria from underneath your fingernails could cause a skin infection, according to Vreeman.
An infected bite might also itch more than an uninfected one. Treat the bite with an antibiotic ointment.
And scratching will temporarily inflame the bite further.
