35 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. 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.
3. 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.
4. 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 tumours. 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.
5. 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.
6. 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 the so-called all-cause mortality, but the evidence isn’t strong for overweightness. A recent review looked at 10 studies of more than 1,90,000 people and found that overweight people had the same longevity as normal weight adults, though they did have a higher risk of heart disease.
7. 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.
8. 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 forwards and pinch your nose shut for 10 minutes.
9. 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.
10. 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—in fact, 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.
11. Carrots help your eyesight. Myth! Carrots get their vision boosting reputation from the chemical that gives them their orange colour: 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 (Wild Cabbage) and spinach.
12. Stress will give you an ulcer. Myth! The two main causes of stomach ulcers are overuse of NSAIDs (Non-steroidal anti-inflammatory drugs) such as aspirin and ibuprofen, and infection from the bacteria Helicobacter pylori. Stress might make an existing ulcer worse (and ulcers might trigger stress), but the current science shows it isn’t a direct cause.
13. 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.
14. 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.
15. 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.
16. 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 hand-grip strength.
17. 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.
18. 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.
19. 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 orthopaedic surgery and medical director of spine trauma surgery at Cedars-Sinai Spine Centre, Los Angeles, USA. “Sitting up straight for too long without a break can also cause strain.” While sitting, keep your lower back supported and your legs uncrossed with your knees at a 90º angle, and get up to stretch every half hour or so.
20. People with dark skin can’t get skin cancer. Myth! Dark skin is less likely to burn, but it isn’t immune to harmful ultraviolet rays and the damage they cause. People of all skin types need to use sunscreen.
21. 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 Centres for Disease Control and Prevention recommends adults get at least seven hours of sleep for optimal health.
22. 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.
23. 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.
24. 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 4,00,000 adults found that eating an egg a day increased good cholesterol and cut the risk of cardiovascular death by 18 per cent.
25. You can stop taking antibiotics when your symptoms go away. Myth! Even if you’re back in tiptop 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.
26. You should rinse the toothpaste from your mouth after brushing. Myth! When you rinse with nonfluoride 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.
27. 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.
28. Running is bad for knees. Myth! Research has found that recreational runners are not at increased risk of having symptoms of knee arthritis or other orthopaedic 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.”
29. 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.
30. 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.
31. 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.
32. Probiotics can help ease diarrhoea. Truth! While studies haven’t pinned down which ‘good’ bacteria, yeast strains and doses are most helpful against diarrhoea, the research is promising. There’s evidence that probiotics can prevent or reduce diarrhoea 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.
33. 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 staying off sweets can have an indirect anticancer effect.
34. Holding in a fart can damage the gastrointestinal 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 neighbours 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.
35. 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.”