�

Weather has always influenced the way people live, determining what they eat, how they dress and the kind of diseases they grapple with. Often, cold, heat or relentless sun are a source of ailments with varying consequences but a common cause: extreme temperatures.�

�

Damage from the sun
Summer brings with it a large number of problems associated with heat. The biggest and most common are sunstroke and heat flashes. The first is the body's response to excessive exposure to the sun. The hardest-hit organ is the head. The symptoms include headache, a bloated face, a feeling of fatigue, muscle cramps, convulsions, excessive sweating and circulatory and respiratory disruptions. There may also be nausea and vomiting.

�

Heat flashes have a similar cause but may appear even if the person has not been directly exposed to the sun. A high temperature with lots of humidity may be enough. The risk increases when the temperature goes above 30 �C and the humidity is more than 40 percent. The problem stems from a failure in the body's temperature-regulating mechanisms. In these cases, even though the signs of the ailment are similar to those of sunstroke, the person will have dry skin, since there is little sweat. The skin is also red and very hot. In fact, if a person experiencing sunstroke does not sweat, he or she can slip into a heat flash. Overweight people are particularly vulnerable because they have a harder time sweating, as well as older people, cardiovascular patients and people who suffer from malnourishment. Also, remember that doing strenuous exercise in hot weather can lead to a heat flash.�

�

Learning prevention
To avoid these two problems, physical activity should be done early in the morning or in the evening. Always cover your head, stay in cool, well-ventilated areas and consume lots of fruit, fresh juice and water. Also, avoid drinking a lot of alcohol because it contributes to dehydration. If symptoms have already appeared, first aid involves taking the patient to a cool, shaded place, applying cool compresses and giving him or her water to drink little by little. A fizzy aspirin tablet may also help. If the problem is heat flash, don't give aspirin. Try to lower the person's temperature by bathing them in cool water. If the symptoms do not subside, call or go see a doctor.

�

When temperatures drop
But health problems can also arise when temperatures fall, and it doesn't have to be snowing. The ocean or rivers can cause disruptions in digestion because of the cold water. The problem stems from a sudden lack of blood supply to the brain and heart. The blood has to reach the surface of the body to maintain its internal temperature. Sometimes the problem arises simply from drinking very cold beverages or spending a long time in places that are draughty or too cold. The latter are also the cause of those pesky summer colds, which stem from abrupt changes in temperature.

�

There are theories which say cold does not cause a cold, but rather that the latter comes from germs whose spread and contagion have nothing to do with temperature. However, we do know that excessive cold lowers the temperature of nasal mucous, making it easier for cold-causing agents to get inside the body. Indeed, as necessary as it may be in summer, air conditioning has many critics for this and other reasons. It dries out the air, and if the stream of cold air is not aimed properly and hits a certain part of the body head-on, it can cause muscle contractions, especially in the neck and back area. Also, the fact that air conditioned rooms are sealed shut so that the cold does not escape leads to improper ventilation in which viruses floating around the air have an easier time infecting people.�