25 Things You Probably Didn't Know About Your Body and Health

In the spirit of those annoying, addictive, you-know-you're-reading-them-even-though-you-wish-you-weren't Facebook notes popping up everywhere, Health.com presents its list of 25 random things you might not know about the human body, nutrition and exercise, sex, sickness, and health. Go ahead: Pass it on to your friends.

1. Rinsing your nose with salt water can help keep you healthy and ward off allergy symptoms. Nasal irrigation is a cheap and easy way to find relief if you have spring allergies, nasal congestion, stuffy noses or post-nasal drip, says Dr. Melissa Pynnonen, co-director of the Michigan Sinus Center and an assistant professor in the University of Michigan's department of otolaryngology.

2. Dogs can smell cancer and low blood sugar. The Pine Street Foundation, a cancer-education and research center in San Anselmo, Calif., published a study showing it was possible to train dogs to identify, based on breath samples, which patients had lung and breast cancer. Now the organization is recruiting ovarian cancer patients and dogs for a new study. In diabetics, the presence of ketones—substances made by the body during the metabolic process—can be smelled in urine and on the breath when blood sugars are high. Dogs can pick up on other smells that humans can’t when glucose levels drop.

3. Researchers at Cornell University found that people who pass through an entryway near the kitchen tend to eat 15 percent more than those who use the front door.

4. You're more likely to have a heart attack on a Monday, or up to three days after you've been diagnosed with the flu or a respiratory tract infection. The risk of dying from a heart attack increases by a third during outbreaks of the flu and related respiratory diseases, found researchers at the University of Texas Health Science Center at Houston. The study authors estimate that 90,000 coronary deaths could be prevented a year in the United States if more heart patients simply got a flu shot.

5. You can't get a tan from your computer screen. The Computer Tan Web site was created as a hoax to raise awareness about skin cancer.

6. Obese people spend approximately $485 more on clothing, $828 on extra plane seats, and $36 more on gas each year than their thinner counterparts. Researchers say an overweight driver burns about 18 additional gallons of gas a year. Plus-sized clothing costs 10 percent to 15 percent more than smaller-sized clothes. When it comes to jet fuel, a recent issue of the American Journal of Preventive Medicineestimated that the extra weight of obese Americans caused airlines to spend $275 million to burn 350 million more gallons of fuel.

7. Smokers are four times as likely to report feeling unrested after a night's sleep than nonsmokers. Smokers often experience withdrawal symptoms at night, thus causing periods of restlessness and waking. Smokers were also 1.69 times as likely to develop hearing loss than non-smokers, as smoking may affect antioxidative mechanisms or the blood vessels that feed the auditory system.¹

8. Eating fruits and vegetables may help the human body make its own aspirin. Findings from the Journal of Agriculture and Food Chemistryindicate that study participants who received benzoic acid, a natural substance in fruits and vegetables, could make their own salicylic acid, the key component that gives aspirin its anti-inflammatory and pain-relieving properties.

9. A 20-minute nap can improve your overall alertness, boost your mood, and increase productivity. William Anthony, co-author of The Art of Napping at Work (Larson Publications, 1999),says the post-nap boost can last for several hours. In addition, your heart may reap benefits from napping. In a six-year study of Greek adults, researchers found that that men who took naps at least three times a week had a 37 percent lower risk of heart-related death.

10. Your kitchen sink is dirtier than your bathroom: There are typically more than 500,000 bacteria per square inch in its drain. The faucet, basin, and sponge are crawling with germs as well. Bacteria colonies with a total population exceeding 50 million can live on a single dirty sponge. And just think—that's what you use to wipe down countertops, forks and drinking glasses.

11. Four out of five doctors in the UK don't work out enough. Heavy workloads, lack of time and poor motivation contributed to the lack of exercise.²

12. Baking soda can whiten teeth, garlic can help treat athlete's foot, and honey can soothe a hangover.

13. Using a food diary can double a person's weight-loss efforts. Your food diary makes you accountable to yourself and provides you with clues on where the extra calories are sneaking in.

14. Regular exercise can lower a woman's cancer risk—but only if she's getting enough sleep. The National Cancer Institute followed 5,968 women for almost 10 years, during which 604 of them developed some form of cancer. Women in the top half of physical activity levels showed an approximate 20 percent reduction in cancer risk compared to those who exercised less. For a segment of those women, sleeping less than seven hours per night had a decreased benefit to exercise. Their cancer risk was greater than those who exercised but slept more—but still lower than those who exercised the least.

15.Watching yourself run in a mirror can make a treadmill workout go by faster and feel easier.

16. Third-hand smoke—the particles that cling to smokers' hair and clothing and linger in a room long after they've left—is a cancer risk to young children (and pets).

17. Walking against the wind, in the water, or while wearing a backpack burns about 50 more calories per hour than walking with no resistance. People who wear pedometers also tend to burn more calories and lose more weight.

18. Trained sexologists can infer a woman's orgasm history by observing the way she walks.³ In other research news, men find women who wear red sexier than those who wear "cool" colors such as blue and green.

19.Foreign accent syndrome and exploding head syndrome are real (but very rare) medical conditions. The American Sleep Association explains that a person with exploding head syndrome experiences a a loud, indecipherable noise that seems to originate from inside the head. 

20. Vitamins don't seem to help older women guard against cancer or heart disease.

21. Some men experience pain, headaches, or sneezing as a result of ejaculation. The increased activity in the nervous system during orgasm may be the culprit in triggering headaches.

22. Germ-killing wipes can spread bacteria from one spot to another if you reuse them. Researchers at the Welsh School of Pharmacy at Cardiff University in Wales issued their concern on the use of the wipes in hospitals and the importance of a routine surveillance program in reducing risks of infection to patients.

23. Oatmeal, citrus fruits, and honey can boost your sex drive and improve fertility. Oats produce a chemical that releases testosterone into the blood supply, increasing sex drive and orgasm strength. Vitamin C found in citrus fruits improves sperm count and motility, while vitamin B from honey helps the body use estrogen, a key factor in blood flow and arousal. 

24. Twenty-nine percent of Americans say they have skipped filling a prescription due to the cost, and 23 percent use pill splitting as a way to save money.

25. Facebook may be good for your health: Studies show that staying in touch with family and friends can ward off memory loss and help you live longer.