50 HEALTH FACTS Your Doctor Wants You to Know

Knowing which of these statements have been verified by SCIENCE—AND which are Myths—could boost your health

1 Cold weather makes you sick.

Myth! Germs are the only thing that can make you sick. You can go out in the freezing cold with wet hair, and if there aren’t any germs around, you’ll stay sniffle-free. But there is a correlation: The viruses that cause the common cold thrive in low temperatures.

2 Not all heart attacks involve chest pain.

Truth! A 2012 study of more than

1.1 million heart attack patients found that 31 percent of men and 42 percent of women didn’t have any chest pain before being hospitalized. The American Heart Association recommends calling 911 for other symptoms, too, including shortness of breath, light-headedness, and pain elsewhere in the upper body.

3 Being overweight shortens your life expectancy.

Myth! It’s what researchers call the “obesity paradox,” though the “overweight paradox” would be more accurate. Obesity is linked with a host of health problems, including so-called all-cause mortality, but the evidence isn’t strong for overweightness. A recent review looked at ten studies of more than 190,000 people and found that overweight people had the same longevity as normalweight adults, though they did have a higher risk of heart disease.

4 You shouldn’t ice a burn.

Truth! Most skin damage from a burn comes from the inflammatory response, and ice can damage cells and make it worse. Instead, immerse the burn in cool water for about five minutes. Then wash with mild soap and apply an antibiotic ointment.

5 Antiperspirants cause cancer.

Myth! Antiperspirants temporarily keep sweat from escaping, and some scientists have suggested that letting it build up in the ducts could cause tumors. But research hasn’t confirmed that theory, and the largest study to date on the subject found no link between cancer and antiperspirants or deodorants.

6 CPR doesn’t require mouth-to-mouth breathing.

Truth! A 2017 study found that when bystanders gave CPR to people in cardiac arrest, survival rates were higher when they employed uninterrupted chest compressions rather than pausing for rescue breaths.

7 Carrots help your eyesight.

Myth! Carrots get their vision-boosting reputation from the chemical that gives them their orange color: beta-carotene. Beta-carotene is converted into vitamin A, which helps your eyes see better in the dark. But the conversion process isn’t very efficient, and once you’ve taken in a certain amount, the body stops converting it. For improved eyesight, eat vegetables high in vitamin A itself, including leafy greens such as kale and spinach.

8 Eating too much sugar will give you diabetes.

Myth! Sweet foods don’t directly lead to chronically high blood sugar. But they can contribute to obesity, which is a risk factor for diabetes, so keeping a well-balanced diet and limiting treats is still the right idea.

9 You shouldn’t let someone with a concussion sleep right away.

Truth! For several hours after the initial blow, it’s a good idea to keep the person awake and monitor symptoms. But after that, taking naps and getting plenty of sleep at night are recommended to aid recovery.

10 Tilt your head back if you have a nosebleed.

Myth! Tilting your head back might make you swallow blood, which could irritate the stomach and potentially make you vomit. Instead, tip your head slightly forward and pinch your nose shut for ten minutes.

11 You should eat several small meals throughout the day instead of three big ones.

Myth! While some people who are natural grazers might do better on a small-meal eating plan, others won’t feel satisfied, and the diet will backfire. The goal should be to pay attention to the overall nutrients and calories you’re getting in your meals, not to how you’re spreading them out.

12 Waking up sleepwalkers will give them a heart attack.

Myth! Sleepwalkers might be disoriented or distressed if you manage to wake them up, but you won’t put them at risk of a heart attack or coma. Your best bet is to guide the person back to bed or wake the person gently so he or she won’t be startled.

13 Coffee will dehydrate you.

Myth! The idea that caffeine is a diuretic that leaves your body short of fluids doesn’t hold water. In fact, studies show that coffee and tea drinkers don’t use the bathroom any more than water drinkers. A cup of joe counts as part of your fluid intake and can actually help you hydrate.

14 A person having a seizure is at risk of swallowing his or her tongue.

Myth! Following conventional wisdom and putting a spoon in the person’s mouth won’t prevent tongue swallowing, but it could harm the teeth or jaws. Instead, turn the person on his or her side to prevent choking on saliva or vomit, and cushion the head with a pillow.

15 Frostbitten skin shouldn’t be warmed up by a heater.

Truth! Frostbite numbs the skin, so it could be burned without your realizing it if it’s next to a radiator, fire, or heating pad. Instead, immerse the area in warm water.

16 Peeing on a jellyfish sting will help reduce the pain.

Myth! Urine—or even fresh water— could actually trigger more venom, making the sting even worse. Carefully pluck out any tentacles and rinse with vinegar if you can.

17 Stress will give you an ulcer.

Myth! The two main causes of stomach ulcers are overuse of NSAID painkillers, such as aspirin and ibuprofen, and infection from the bacteria Helicobacter pylori. Stress might make an existing ulcer worse (and having an ulcer might trigger stress), but the current science shows it isn’t a direct cause. 18 You should return to working out after a heart attack.

Truth! “Too often, heart patients use their condition as an excuse to cut back on physical activity when they should be doing the opposite,” says Salim Virani, MD, chair of the American College of Cardiology’s Prevention of Cardiovascular Disease Council. Hitting the standard 20 to 30 minutes most days can help strengthen your heart. Talk to your doctor about creating a safe routine.

19 Bar soap is covered in germs.

Myth! You might transfer germs to the soap while you scrub up, but they won’t last long enough to spread. The most rigorous study on the subject, published in 1965, found that bacteria on a bar of soap die within minutes and are not transmitted to the next person to use the soap.

20 Eggs are bad for your heart.

Myth! The old thinking was that cholesterol in food would raise blood cholesterol levels and in turn increase the risk of heart disease. A recent study of more than 400,000 adults found that eating an egg a day increased good cholesterol and cut the risk of cardiovascular death by 18 percent.

21 Reading in dim light will harm your eyes.

Myth! It might tire your eyes in the short term, but there’s no evidence that it will do any lasting damage. When reading, position light to shine directly on the page rather than from over your shoulder to reduce glare.

22 Coughing too much can make you throw up.

Truth! Little kids are especially prone to vomiting after coughing fits because their gag reflexes are extra sensitive, but it can also happen to adults. It usually isn’t a big deal, but if you keep puking, see a doctor.

23 Cracking your knuckles will give you arthritis.

Myth! Recent studies haven’t found a link between cracked joints and arthritis. But some studies showed that cracking your knuckles can result in soft-tissue damage (which can cause swelling) and a decrease in handgrip strength.

24 You don’t need eight glasses of water every day.

Truth! There’s no scientific evidence that eight is the magic number. You might need more or less than that, depending on factors such as climate and body size. To make sure you are getting enough, just drink water throughout the day.

25 Sitting up straight can be bad for your back.

Truth! “Hunching can certainly be bad for your back. But the opposite is true, too,” says Neel Anand, MD, professor of orthopedic surgery and medical director of spine trauma surgery at Cedars-sinai Spine Center in Los Angeles. “Sitting up straight for too long without a break can also cause strain.” When you’re sitting, keep your lower back supported and your legs uncrossed with your knees at a 90-degree angle, and get up to stretch every half hour or so.

26 People with dark skin can’t get skin cancer.

Myth! Dark skin is less likely to burn, but it isn’t immune to harmful UV rays and the damage they cause. People of all skin types need to use sunscreen.

27 If you don’t have a bull’s-eye rash, you don’t have Lyme disease.

Myth! About 20 to 30 percent of people with Lyme disease will never develop that classic rash. Other symptoms to watch for include fever, headache, achy muscles, and swollen lymph nodes and joints.

28 You need less sleep as you get older.

Myth! Older adults often sleep less as a result of chronic conditions that are more common with age as well as the medications used to treat them. But that doesn’t mean they require less sleep. While sleep needs vary from person to person, the CDC recommends most adults get at least seven hours of sleep for optimal health.

29 Holding in a sneeze is unhealthy.

Truth! As your body gets ready to sneeze, pressure builds in your lungs. When your body tries to push the air out, it needs somewhere to go— and if you’re pinching your nose and mouth, it could be rerouted to the ears. In rare cases, sending the sneeze in that direction can lead to damage such as ruptured eardrums.

30 You can get the flu more than once a season.

Truth! Every year, there’s more than one flu strain circulating. Getting sick from (or being vaccinated against) one of them won’t protect you or your loved ones from the other strains. That’s why it’s important to take everyday preventive actions during flu season: covering your nose and mouth with a tissue while coughing or sneezing, and washing your hands often with soap and water.

31 Leeches are a legitimate medical treatment.

Truth! In 2004, the FDA officially approved using leeches on some postsurgical patients. This is a far cry from the bloodletting of olden days, which was thought to drain disease from the body. That doesn’t work, but studies show that the bloodsucking creatures can safely keep blood from coagulating, which is helpful when surgery patients are at risk of their blood pooling.

32 Eating too much soy can cause cancer in women.

Myth! Soy is a plant estrogen, which made some scientists jump to the conclusion that it could disrupt women’s estrogen hormones and lead to breast cancer. In fact, some studies suggest soy could actually reduce breast cancer, though more research needs to be done.

33 You can stop taking antibiotics when your symptoms go away.

Myth! Even if you’re back in tip-top shape, continue taking your meds as prescribed. The symptoms can fade before the infection clears, meaning you could get sick all over again— and this time it might be more resistant to the antibiotic.

34 You should rinse the toothpaste from your mouth after brushing.

Myth! When you rinse with non-fluoride mouthwash or water, you’re spitting out the fluoride that prevents tooth decay without giving it enough time to work. If you still feel like you need to rinse, studies suggest using a tiny bit of water to swish the toothpaste foam, then spitting it out. This will keep more fluoride on your teeth.

35 Running is bad for your knees.

Myth! Research has found that recreational runners are not at increased risk of having symptoms of knee arthritis or other orthopedic problems. “In fact,” says James Smoliga, PHD, associate director of High Point University’s Human Biomechanics and Physiology Laboratory, “running may strengthen muscles that stabilize the knee, which may help prevent injuries and arthritis.”

36 Sugar causes cancer.

Myth! It’s true that cancer cells tend to get their fuel from sugar, but that doesn’t mean that eating less sugar will prevent or slow down cancer. The body makes its own glucose when you eat less sugar, which could negate any cancer-fighting benefit. That said, obesity is a risk factor for certain cancers, so keeping your hands out of the cookie jar can still have an indirect anticancer effect.

37 Alcohol warms you up when it’s cold outside.

Myth! You might feel warmer and your face may start to flush as you sip that hot toddy, because alcohol causes your blood vessels to dilate, moving warm blood closer to the skin. But this perception of warmth also causes you to stop shivering, which actually brings your core temperature down.

38 Vaccines can cause autism.

Myth! Some people have raised concerns that substances used in trace amounts in certain vaccines— including formaldehyde, aluminum salts, and thimerosal, a mercurybased preservative—could cause autism. But none of these substances has been shown to cause harm in the small doses used in vaccines. Nor is there any evidence that multiple or combination vaccinations, such as those recommended for children, can weaken the immune system and trigger autism, as some people fear.

39 Women should be as worried about colorectal cancer as men are.

Truth! Colorectal cancer is the third most common type of cancer among men but the second most common for women. Men do have a slightly higher risk overall: About 1 in 22 men will develop colorectal cancer, compared with 1 in 24 women.

40 Caffeine is good for hearts.

Truth! It might seem as if anything that makes your heart race would put stress on your ticker, but mounting evidence says just the opposite. Studies suggest that drinking three cups of coffee a day is linked to a lower risk of cardiovascular problems. The antioxidants in coffee may play a role, and caffeine might speed up cellular processes that help repair the heart.

41 A workout won’t counteract the effects of sitting all day.

Truth! A study of almost 8,000 adults found that people who sat the longest overall and for the longest uninterrupted time had the greatest risk for death, regardless of whether they’d squeezed in a workout. That’s not to say exercise is useless, but it’s important to scatter activity throughout the day in addition to a designated workout.

42 Poison ivy is contagious.

Myth! The only way to develop a rash is to come in contact with the plant or its sap yourself. You cannot catch the itch from someone else—as long as that person washed the sap off.

43 Sitting too close to the TV damages your eyes.

Myth! Until the late 1960s, the amount of radiation coming from TVS wasn’t well regulated, so some people worried that sitting too close could cause health problems. Modern TVS don’t pose that risk. Staring at anything for a long time can make the eyes feel tired, but it won’t do permanent damage.

44 Probiotics can help ease diarrhea.

Truth! While studies haven’t pinned down which “good” bacteria, yeast strains, and doses are most helpful against diarrhea, the research is

promising. There’s evidence that probiotics can prevent or reduce diarrhea associated with antibiotics and can ease symptoms in people with irritable bowel syndrome. Other potential benefits of probiotics include weight loss, cold prevention, and protection from tooth decay, though the studies aren’t conclusive.

45 The flu shot might give you the flu.

Myth! Vaccines do contain inactivated viruses in order to produce an immune response. You might experience minor side effects after your shot, such as aches or a low-grade fever, but unless you have a compromised immune system, it’s unlikely that you’ll get the full-blown flu.

46 Alzheimer’s and dementia are two separate conditions.

Myth! The term dementia refers to an umbrella of disorders that affect brain functioning; Alzheimer’s is one of these diseases.

47 Crickets are a healthy alternative to meat.

Truth! A study in the European Journal of Clinical Nutrition found that edible insects aren’t any less healthy than chicken or beef, and they might even have some advantages— more calcium, for instance. Another study found that, compared with having a traditional breakfast, eating crickets in the morning reduced markers of inflammation in the gut.

48 Holding in a fart could damage your GI tract.

Myth! For better or for worse, when you hold back your gas, that flatulence stays right where it is. Eventually, your body will expel it when you aren’t paying attention, no harm done (at least to you—your neighbors might disagree). The only time it could potentially cause harm is if your colon is severely blocked and the pressure builds up to the point of bursting—and even then it’s rare.

49 Caffeine stunts growth.

Myth! People used to think caffeine would leach calcium from the body, meaning weaker bones and slower growth. Newer research suggests that teens can safely drink up to 100 milligrams of caffeine per day (about one cup of coffee or two to three cans of cola).

50 Depression is incurable.

Myth! “Recovery from depression is not only possible; it’s actually likely when people receive the specific kind and amount of help that they need,” says Mark Henick, MS, a mental health advocate.

“When you combine medication with psychological therapy as well as social supports like housing, employment, and engagement, that’s the gold standard for recovery.”