Going out in winter with wet hair means you're more likely to catch a cold
This old wives' tale seem to make perfect sense, but there is actually no correlation between feeling cold and catching one. More likely, people get sick more often in cold weather because we tend to congregate indoors, passing viruses more readily. Many experiments have investigated the temperature-illness relation over the years, but it’s been found time and time again that chilled and non-chilled participants all caught the rhinovirus at the same rate. Today, some research even suggests that cold temperatures actually stimulate our immune systems, helping protect against sniffles in the future.
Reading in the dark will ruin your eyesight
While it’s true that reading in dim light makes your eyes work a little harder, there is no evidence to suggest that the practice is detrimental in the long run. Like any muscle, eyes may get tired from having to let in as much light as possible while focusing on small text, and they may dry up a little. But this eye fatigue is far from irreversible, unless you read only in the dark, all the time. But then you have other problems to worry about.
You should drink eight glasses of water a day
This myth is based on a game of telephone. Back in 1945, a government agency recommended that we need around eight glasses of fluid per day for optimal health. The eight glasses fact stuck, but what people didn’t notice was that the experts said "fluid" -- which includes coffee, juice, pop etc. -- and not necessarily that we need to drink it (most of our food today contains water). Also, the advice is over 65 years old. This notion has been thoroughly debunked today. So, if you feel thirsty, drink something. If you don’t, don’t.
You should never wake a sleepwalker
About 20% of the population is prone to sleepwalking, which tends to run in the family. Chances are, a lot of these people are going to hurt themselves if left to wander around dark houses in the middle of the night (not to mention those who attempt to cook, eat and drive). It’s commonly believed that waking sleepwalkers will lead to them becoming angry and disoriented, but at the more ridiculous end of the scale, some believe it increases risk of a heart attack. If you’re worried, just guide the person gently back to bed. That should do the trick.
You lose most of your body heat through your head
Time for a little logic here: If your head is uncovered but the rest of your body is, you will clearly lose more heat from up top. However, if your head is covered but an arm or leg is exposed, then that’s where heat will escape. This myth seems to have arisen from an old military study that left soldiers outside (with bodies completely covered) without hats and found significant heat loss through the head. Since then, it has been shown that we actually lose about 10% from our heads and the rest from other parts of the body. So you’ll feel a breeze whether you leave the house without pants or without a beanie.
Skipping meals helps you lose weight
Here’s the reality: No matter how good you think your self-control is, if you skip one meal, you will overeat at the next. It’s been proven. Many times. Eating regularly means your metabolismis working hard and burning calories while turning the food you’ve eaten to energy. When you’re not eating, it switches to standby mode, and fewer calories are being burned. The longer you starve yourself, the slower your metabolism will get, eventually resulting in a less efficient calorie-burning system. So skipping meals in the long run can actually make you gain weight. Also, if you’re combining meal-skipping with exercise, you will have less energy for exercise, and workouts will be less productive.
We only use 10% of our brain
Here’s the thing: We do use all of our brain, just not all at once. Brain damage studies are one of the ways the 10% myth has been disproven. No matter which part of the brain is injured, it affects performance in some way. Brain-imaging technologies show the same thing. So those who have been hoping to tap into the other 90% for telekinesis need to get off their asses and get the remote control themselves.
Cracking your knuckles will cause arthritis
If every crack of a knuckle took us one step closer to arthritis, there would be a lot more aching hands in the population. That pop you hear has nothing to do with the bones; it’s the sound of a small bubble of gas bursting, and there is no evidence to show that it will lead to arthritis, which is most often a symptom of plain old age, weight pressure or previous injury. But if you are a regular cracker, you might want to ease off. It has been shown that it does slightly weaken finger joints, leading to a less impressive grip later in life.
Alcohol kills brain cells
Your slurred speech Saturday night and the Sunday morning hangover may make you feel like you’ve dropped a hundred IQ points, but the actual fact is that drinking (unless you’re drinking pure alcohol, the disinfectant) won’t kill your brain cells. If you’re a raging alcoholic, you might be looking at some damage to how your neurons communicate, but this impairment is largely reversible. The liver problems, not so much.
Eating at night makes you fat
Let’s get this straight: A calorie is a calorie, and calories don’t watch the clock and turn into villains of the night after 6 p.m. You get fat by taking in more calories than you burn, so Krispy Kremes at night are no worse than Krispy Kremes in the morning. What does tend to happen is that people who wait to eat until late evening when they’re super hungry, or are mindlessly snacking on the sofa, consume more. If you eat a huge meal and then lie down to sleep, you may find it hard to drift off, but that’s about it.