When Healthy Habits Backfire
Some Healthy Habits Can Cause Trouble; Find Out What to Do
3. Getting a “base tan.” Despite all the negative publicity they’ve gotten in recent years, tanning salons remain popular -- especially with young people. Some people schedule a few sessions of indoor tanning prior to leaving for a sun-filled vacation, believing that a base tan will enable them to avoid sunburn and to tan deeply with less damage to their skin. Not so. “The pigmentation in tanned skin amounts only to an SPF of about 4, so getting a base tan provides almost no additional protection from the sun,” says June Robinson, MD, professor of clinical dermatology at Northwestern University Feinberg School of Medicine in Chicago. More to the point, she says, any degree of tanning damages the skin, causing premature aging and raising the risk for skin cancer. So forget about tanning salons, and heed the familiar advice when venturing outdoors in sunny climes: avoid the sun between 10 a.m. and 2 p.m., when solar radiation is strongest; at other times, wear sun-protective clothing, including a broad-brimmed hat, pants, and a long-sleeved shirt, and make liberal use of sunscreen (SPF 30 or higher).
4. Drinking water. From constipation to kidney failure, the risks of dehydration are well known. But drinking more water than your body needs can cause a perilous drop in the concentration of sodium in the bloodstream. This condition, known as hyponatremia, can trigger fatigue, headache, nausea, and vomiting; severe cases can be fatal. Hyponatremia is more common in people with kidney disease and congestive heart failure, but it also affects athletes -- who, mindful of the need to replace water lost through perspiration, often gulp water during endurance events. In 2002, researchers at Harvard University Medical School tested participants in the Boston Marathon and found that 13% were suffering from hyponatremia. Experts say healthy people should drink according to thirst, ignoring the familiar admonition to consume eight 8-ounce glasses of water a day. “The eight-by-8-ounce rule can potentially lead to diluting the kidneys and impair kidney function,” says Joseph Stubbs, MD, president of the American College of Physicians and an internist in private practice in Albany, Ga. What if you’re running a marathon or competing in another endurance event? “Guidelines generally recommend [consuming] no more than eight ounces every 45 to 60 minutes of exercise,” Stubbs says. “But that can vary according to how much sweating one does.”