Weather and Headaches
Headaches are an extremely common problem. According to the American Council for Headache Education, nearly 90 percent of men and 95 percent of women report having had at least one headache in the past year. There are several kinds. Tension-type headaches are the most common, accounting for 75 to 90 percent of all headaches. They're characterized by steady pain affecting both sides of the head. A migraine is a vascular type of headache characterized by intense, throbbing pain on one side of the head. About 25 to 30 million Americans are affected by migraines. Three out of four patients are women. For some, the symptoms of migraine can be extremely debilitating. Cluster headaches affect about one percent of Americans. They're characterized by brief but severe pain centering around one eye. The eye may appear red and watery and patients may have nasal congestion on the affected side of the face. The headaches occur in clusters lasting several weeks to several months. About 85 to 90 percent of patients are males.
Many people report an onset or worsening of headache symptoms during certain weather conditions. For some migraine sufferers, a coming change in the weather can trigger a headache. Researchers believe the drop in barometric pressure that precedes bad weather affects certain parts of the brain and leads to a migraine in susceptible people. Extreme heat and cold are also known migraine triggers. For some people changes in the season may trigger cluster headaches. These headaches are most likely to occur during the transition from spring into summer and from fall into winter. Researchers believe changes in the levels of sunlight may be the factors that trigger the onset of seasonal headaches.
Temperature and Health
Extreme temperatures can take a toll on the body, especially on infants, the very old, and patients with severe chronic medical conditions. Exposure to extremely cold temperatures can cause frostbite, or frozen skin. The fingers, toes, cheeks, nose, and earlobes are at greatest risk for developing frostbite. Symptoms include changes in the coloring of the skin (to a white or yellow color), itching or burning, and numbness, redness, or swelling of the skin. Severe frostbite can cause the skin to blister and harden, eventually leading to the death of tissue in the affected area.
Another risk of extreme cold is hypothermia, a condition caused by dangerously low body temperature. Normal body temperature is about 98.6 degrees F. Hypothermia begins to set in at a body temperature of about 96 degrees F. The body first reacts by shivering to produce heat. Other symptoms may include confusion, sleepiness, slurred speech, shallow breathing, weak pulse, and low blood pressure.
At the other extreme of the spectrum is heat. As temperatures rise, the body sweats to remain cool. If it gets too hot and/or humid, the body is unable to cool down, leading to heat illness. Excessive sweating can deplete the body's stores of salt. When combined with low fluid intake, it can lead to heat cramps. These are painful spasms of the muscles due to a lack of salt. It's more common in people who exercise heavily in hot weather. Heat exhaustion sometimes occurs after several days of high temperature and inadequate fluid intake. It can lead to profuse sweating, muscle cramps, weakness or tiredness, paleness, dizziness, headache, and nausea or vomiting. Without treatment, heat exhaustion can progress to heat stroke. As the patient's temperature rises, sweating is no longer effective and the body is unable to cool down. Body temperatures may reach 106 degrees or higher, leading to a stroke. A heat stroke can cause permanent disability or stroke. The elderly, patients with high blood pressure, and people who work outdoors are most at risk for heat-related illnesses.
Cold and hot weather also have effects on health. In cold weather, the hair and nails tend to become more dry and brittle. The skin loses moisture, leading to itching and aggravation of skin conditions (such as eczema). Cold weather is often accompanied by snow, sleet, and freezing rain, increasing the risk of automobile accidents and home injuries (i.e., falls on icy steps, snow blower accidents, or overexertion during shoveling). Less sun in the colder months can cause depression in susceptible people.
In the summer, people tend to spend more time outdoors. Without protection, excessive exposure to the sun can lead to sunburn and increase the risk of developing skin cancer. In urban areas, hot, humid weather traps air pollutants close to the ground, increasing the risk breathing difficulties in people with chronic respiratory problems.
Biometeorology and Health
Biometeorology is the study of how weather affects the health of humans, animals, and plants. To study the interaction between the two, researchers look at historical weather data. They look for the emergence of weather patterns and correlate those events with health records and reports. Today, analysts are using the historical data and high-powered computers to look at emerging weather patterns and predict adverse effects on human health.
There are currently several ways biometeorology is used in the U.S. today. The UV (ultraviolet) index is a forecast of the strength of the sun's rays. The higher the index, the greater the exposure to UV radiation, and the greater the risk of developing sunburn and skin cancer. Air quality indexes correlate the temperature, humidity, wind, and other factors along with estimated pollution levels. People at risk for breathing problems may be advised to stay indoors when air quality levels are poor.
Many public health agencies use forecasts of heat index to plan for potential health emergencies. For example, when a heat wave is forecast, authorities can ensure the elderly and other at-risk people have air conditioning, fans, or other ways to remain cool. Farmers can also benefit from the information, because it gives them time to take steps that can minimize damage to crops and animals.
For information on biometeorology:
International Society of Biometeorology, www.biometeorology.org
For information on headaches:
American Council for Headache Education, 19 Mantua Rd., Mt. Royal, NJ 08061, www.achenet.org
National Headache Foundation, 428 St. James Pl., 2nd Floor, Chicago, IL 60614, www.headaches.org
For general information on extreme temperatures and health: American College of Emergency Physicians, www.acep.org
CDC, National Center for Environmental Health, www.cdc.gov/nceh