13 Health Rules You Can Break

You've heard them before: Eat your veggies. Get eight hours of sleep each night. Don't cross your eyes, or they'll stay that way. Many health rules are grounded in science and should be followed as part of a balanced and healthy lifestyle, but others? Not so much. Here are 13 popular rules that aren't as hard-and-fast as you might think.

The myth is that this habit will cause arthritis. It may be annoying, but no medical studies prove cracking or popping your fingers will lead to arthritis. However, some doctors say cracking your knuckles repeatedly may hurt your fingers in other ways (besides driving your coworkers crazy), so it's best to avoid the habit. Ever wondered where the popping sound comes from? When you stretch your fingers you pull the bones, creating an air bubble around the joints. When the bubble bursts, it makes a sound.

It may make you feel chilly (wet hair doesn't insulate well), but it won't make you sick. Colds are caused by a virus that is usually spread by droplets from someone's cough or sneeze. To avoid the virus, you're better off washing your hands often and avoiding crowded places or close contact with someone who's sick. What does make you more vulnerable to a cold virus: fatigue, stress, and certain bad allergies.

Sorry, Mom, but there's no evidence that this causes cramps, which could possibly lead to drowning. While it's true that eating diverts some blood to the digestive system, most experts agree your body can still provide enough blood and oxygen during exercise to keep cramps from happening. Eating a big meal may make you feel too full to knock out a bunch of laps, but it won't make you drown.

As long as you're drinking enough so that you don't feel thirsty, you urinate often, and your urine is nearly colorless, you're probably getting enough water. And remember that magic "eight cups a day" includes water you get from foods and other beverages, and those help you gain other nutrients, too. While water is necessary, some healthy alternatives to H20 include broth-based soups and water-laden produce such as grapes, cucumbers, and melon.

You may get a headache and strain your eyes, but experts say poor lighting will not cause permanent damage to your eyesight. Ditto for sitting too close to a television or computer screen. To reduce eye strain, sit at a comfortable distance and take breaks often—at least every 20 minutes.

While too much of it will cause teeth problems, it’s a common myth that sugar creates hyperactivity in children. This theory was tested in a variety of children, including those believed to be sensitive to sugar. Research found that although children consumed well over their average daily intake, neither table sugar or aspartame—an artificial sweetener—negatively affected the children’s behavior. Other research confirmed these findings.

We’ve all heard this one when someone scoops food off the floor, as if germs stand by with a stopwatch to wait to latch onto food. In 2004, a college student named Jillian Clarke tested this theory and found that it was nothing but a myth. However, her research found that food dropped on carpet attracted fewer germs (but more cat hair) than if dropped on a hard surface.

This has been an English wives tale for centuries, but there’s no concrete evidence to support it. One study found that food and starvation both produced a response from the immune system. When it comes to illness, drinking plenty of fluids is key to a quick recovery. As a general rule, if you’re hungry—the way your body tells you it needs nutrition—you should probably eat.

People living in warm climates are usually warned not to consume too much caffeine because of its diuretic properties (a.k.a. it makes you pee), which could lead to dehydration. A 2002 study from the University of Connecticut, which has since been confirmed by others, showed that people who drank decaffeinated beverages only had a three percent difference in water retention, thus showing that caffeine and caffeinated beverages don’t cause dehydration.

Not everyone needs eight hours of sleep a night. Some people run fine on six while others can barely function without nine. In fact, there’s historical evidence that humans used to sleep in intervals: two hours at dusk, a two-hour waking period, and then a second sleep. The amount of sleep you need varies on a variety of factors, including illness, stress, physical activity, and more. As a good rule, if you awake feeling tired, you probably need more or better sleep.

Yes, milk contains tryptophan, the same sedative found in turkey, but you’d have to drink a few cows’ worth to knock you out for the night. The response people feel from it is entirely psychological, so it can help you fall asleep if you think it will. It has the same comforting effect as wrapping up for the night with your teddy bear.

Every child who has swallowed his gum has heard this one. Chewing gum, just like anything else you swallow, will get picked up by the fluids and other food in your stomach and move it through digestion. It doesn’t even take seven dogs years to get through. It usually only needs a few days at most, just like everything else.