I recently a session at the Asian American Women Leadership Conference to high school and college students about taking care of our bodies. One the topics is common health myths. Despite our best efforts at debunking them, here are 8 pervasive myths:

1. You can catch a cold from being too cold. Growing up, how many of us have heard this from well-meaning parents and grandparents? It’s easy to see how this myth came to be. People do get more colds in the winter. Going outside in the cold without proper protection isn’t particularly pleasant, and if you do it enough, might lead to a weaker immune system. However, we also know that colds are viral infections that are transmitted through viruses. You catch a cold from someone else who has a cold, not from being too cold yourself. So, to avoid catching colds, be diligent about washing your hands (though bundling up in cold weather isn’t a bad idea either).

2. You will get blind if you read in low light. If this is the case, then our ancestors will surely all have suffered from blindness! It’s not true that reading in low light leads to blindness. That said, why strain your eyes unnecessarily? If you have the choice, read in an environment with lighting that is pleasant to you.

3. In order to tan, you must burn first.This is definitely NOT true. Sunburns are potentially dangerous, and can lead to sunstroke and dehydration, not to mention skin cancer. Tanning itself carries similar risks. How much you tan depends on your skin type (there are some people who burn and never tan, for example), but you should definitely not plan to get sunburned in order to tan.

4. Muscle turns to fat if you don’t use it. Anatomically, this just isn’t the case. Muscle and fat are two different types of tissues, and one doesn’t turn into the other. However, there may be some truth overall in that if you don’t exercise, you lose your muscle mass. If you consume the same number of calories as when you were exercising, you will probably gain weight. So make sure to exercise regularly!

5. Alcohol kills brain cells. In junior high, I watched my teacher drop a rat brain into alcohol, and the alcohol seemed to eat away at the brain. So alcohol kills brain cells, right? Well, not exactly. The alcohol that you drink enters your bloodstream, and doesn’t actually attack your brain directly. Of course, there are other ways for alcohol to injure your brain: for example, binge drinking can lead to decrease in breathing and injury to your brain that way, and drinking while driving has many other dangerous effects. As with everything else, drink responsibly, and in moderation.

6. People are fat because they don’t exercise. While exercise is necessary to maintain good health, the primary contributor to being overweight is poor diet. An overweight person will have difficulty losing weight by exercise alone; a good diet with decreased calories is also necessary. Genes also play a role. That doesn’t mean you shouldn’t exercise if you want to lose weight — but make sure you also change your diet.

7. Birth control/HPV vaccine/etc leads to more sex. A myth like is testament to people using anything as “research” to support their views. It’s hard to imagine that anyone will choose to have more sex because they have better information and a few shots in their arm. A better way to think about this is that people are going to be sexually active anyway. Why not empower them with information to make good choices (i.e. birth control and sex education)? The HPV vaccine can guard against cervical cancer; why not protect our young?

8. Women need annual pap smears starting from age 18. This used to be the case, but the guidelines have been revised such that it’s recommended for women to get pap smears every three years, starting from three years after they begin sexual intercourse. This doesn’t mean that you should only see your doctor every three years; an annual woman’s visit is beneficial for a number of reasons, including checking up on your health in general and addressing other aspects of your sexual health.

Many of these myths are partially based on the truth; that’s why it’s so hard to sort them out. Yet, they have been proven time and time again, with a variety of scientific studies, to not be true.

Leana Wen is an emergency physician who blogs at The Doctor is Listening. She is the co-author of When Doctors Don’t Listen: How to Prevent Misdiagnosis and Unnecessary Tests.  She can also be reached on Twitter @drleanawen.