Why you feel better when the sun shines - how weather affects our emotions - column

Nation's Business, April, 1990 by J.W. Savage

Why You Feel Better When The Sun Shines

More than most of us realize, the weather shapes our lives. Changes in the atmosphere can send our emotions to the depths or the heights. The body responds profoundly to changes in temperature, humidity, barometric pressure, and sunlight.

"Weather is a known catalyst for mood swings," says Dr. Norman Rosenthal, a psychiatrist with the National Institute of Mental Health in Bethesda, Md., and author of Seasons of the Mind: Why You Get the Winter Blues (Bantam Books). "As the human body responds to the outside weather elements, it makes inside adjustments that subtly affect our emotional well-being," he says. According to his studies, 92 percent of us are aware of such changes.

Temperature affects the hypothalamus, that part of the brain that serves as the body's thermostat. Sunlight alters the balance of hormones. Changes in humidity and barometric pressure lead to changes in blood flow and the amount of oxygen reaching the brain.

The elation that so many of us feel in springtime is in fact a physiological response to the increased hours of sunlight. As sunlight strikes our skin, it releases a dormant type of vitamin D into the endocrine system of the thyroid, adrenal, and pituitary glands. Ultimately, sunlight helps to trigger the release of the hormones epinephrine and norepinephrine by the medulla of the adrenal glands.

Both hormones stimulate the heart to produce more blood and also constrict the blood vessels, so that blood pressure rises. Additionally, epinephrine speeds up the transformation of glycogen into glucose, or sugar, within the liver. Within minutes of these changes, the body is in high gear. More oxygen flows to the brain, and you feel expansive and upbeat.

But if the mercury keeps climbing, the temperature and humidity in effect "force the human body to boil over," says Dr. Maria Simonson, founder and director of the Johns Hopkins Health and Stress Clinic, in Baltimore. As the body throws off heat through perspiration, blood vessels on the surface of the skin expand. Less oxygen reaches the brain. A pent-up, exasperated feeling grows, and petty annoyances can "become the cause for a major confrontation," Simonson explains.

On overcast days when barometric pressure falls, so too does the level of oxygen in the blood. The weight of the atmosphere pushes down on the skin, constricting capillaries. Less blood - and so less oxygen - gets to the brain. The brain becomes sluggish; it's common to be forgetful or overlook details.

But if it's gloomy outside and you feel grumpy, there's something that can be done. "The key is oxygen," Rosenthal says. As more oxygen is metabolized within the system, the brain "functions more clearly and with purpose." If the sun comes out, take a brisk walk in direct sunlight; or try whistling. Five minutes of even quiet whistling gives a "boost to the oxygen levels in the bloodstream," Rosenthal says. He also recommends that you eat more vegetables and salads during the late winter months and on hot summer days because "they quickly convert into nutrients and give a mental lift."

No matter what the weather, sometimes we must take medication. And when the temperature is in a normally comfortable range - between 72 and 78 degrees Fahrenheit - most medicines have no side effects. But when the temperature is higher or lower, some drugs can cause the body to act contrary to the needs of nature.

Take caffeine. A cup of coffee on a hot day can turn your body into a miniature furnace. The hypothalamus instructs the body to sweat and slow down, but the caffeine in the coffee overrides the order. It mimics the natural hormone epinephrine; blood vessels constrict rather than expand, and instead of slowing down, the heart rate quickens. Some medicines that have the same effect are atropine (Butibel), benztrophine (Cogentine), chlorpromazine (Thorazine), and diazepam (Valium).

The opposite happens when you take common aspirin for a headache or fever. It expands the skin's blood vessels, contributing to the loss of heat - a potentially serious effect in cold weather. Other drugs - alcohol, dextroamphetamine (Dexedrine), insulin, and methysergide (Sansert) - also contribute to heat loss.

Humans are the only creatures who act "contrary to the weather laws of nature," Rosenthal says. Animals give themselves time to adjust to mood shifts by taking cover in a corner or a den, he says, but "social dictates force us to interact with others even though our instincts may be negative." Humans fight nature, he says, "at our own emotional expense."

PHOTO : If you're making a big decision, should you wait for the sun to come out?