You don't need to breathe through your nose when you...


January 11, 1994|By Dr. Gabe Mirkin | Dr. Gabe Mirkin,Contributing Writer United Features Syndicate

You don't need to breathe through your nose when you exercise in very cold weather. It's true that air is warmed much more when it comes through your nose than when it comes through your mouth. However, exercise causes your body to produce large amounts of heat, and air taken through your mouth at 40 degrees below zero during exercise will be warmed almost 100 degrees before it reaches your lung tissue. Air at minus -40 degrees would burn your throat and hurt so much that you would lose interest in exercising and seek shelter.

People who exercise with their mouths closed aren't working very hard. You can't get enough air through your nose to meet your needs for oxygen when you exercise vigorously. The cross sectional area of the openings in your nose is less than 1/10 the opening in the back of your mouth. It's so small that when you pick up the pace, you could turn blue.

You will clear more pollutants breathing through your nose when you exercise in polluted air, but it will slow you down. Most people can exercise safely on polluted days, since the pollutants that you inhale through your mouth during exercise are quickly cleared from your lungs. Small hairs, called cilia, line the tubes leading to and from your lungs. They sweep the pollutants up toward your mouth where you swallow them with your saliva and they quickly pass from your body. On polluted days, you may want to wear a mask or try to exercise early in the morning before automobile exhaust has filled the air.

Q: Professional athletes are such important role models for our children. Why do players chew tobacco and take cocaine when they know these drugs can kill them? -- R.T., Wichita, Kan.

A: Unfortunately, these terribly harmful substances actually can improve athletic performance. Chewing tobacco contains nicotine, which increases a person's attention to detail, improves memory and helps to improve the fine hand-eye coordination necessary to hit or throw a baseball. You can't tolerate large doses of smoking tobacco because eight seconds after you inhale, almost all the nicotine is absorbed through the lungs and reaches the brain in a concentrated form, which is likely to make you feel nauseated and shaky. When you chew tobacco, the nicotine is diluted by blood from the rest of the body, and small amounts of nicotine reach the brain continuously over long periods of time.

Cocaine makes an athlete more aggressive and feel that he can do no wrong. It can help a basketball player to take shots farther out from the basket and dribble successfully around an opponent.

Tobacco causes cancers, heart attacks and lung damage. Cocaine causes heart attacks. When the autopsy reads multiple small areas of dead tissue and cardiomyopathy, the odds are overwhelming that the cause of death was cocaine.

Q: I have very oily skin, which gets worse when I exercise. My doctor recommends that I take Accutane to shut off my oil glands. Won't that make my skin too dry? -- Y.P., Palm Beach, Fla.

A: The oil on your skin is worthless. It doesn't prevent flaking, aging or wrinkling. Dry skin is associated with a lack of water, and wrinkling and aging are associated with a lack of collagen.

The only useful function for skin oil was to help protect humans from the cold when they walked around naked thousands of years ago. The hairs on your body lie close to your skin and have small muscles attached to them called arrectores pilorum. When you feel cold, you develop goose bumps, caused by the muscles pulling on the hairs so they stand out almost perpendicular to your body. The hairs trap air between them in the same way that the fibers in a sweater trap air, helping to keep you warm because air is an excellent insulator. Contraction of the arrectores pilorum muscles also causes hair to press against oil glands at the base of the hair shaft and squeeze oil to the surface of the skin. The oil covers the skin's surface and helps to keep the skin warm by reducing evaporation of sweat from the skin's surface. This was useful to our ancestors, but now humans wears clothes and skin oil has no benefit.

Dr. Mirkin is a practicing physician in Silver Spring specializing in sports medicine and nutrition.


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