It is normal for your body temperature to rise when you exercise. If you have a natural tendency to overheat, however, you may experience heat intolerance -- accompanied by dizziness -- even without exercising. If you are particularly sensitive to heat and tend to get dizzy during exercise, see your physician in order to rule out any type of underlying medical problems.
Symptoms
One of the most common symptoms of heat intolerance is dizziness. When dizziness occurs because of the increase in body temperature, other symptoms may appear as well. You may sweat profusely, overheat or feel extremely hot, faint, or experience heart palpitations, rapid pulse, nausea, vomiting and headaches. Most of these symptoms tend to appear gradually and get worse as you continue to move and exercise. If you have never experienced the symptoms before, or they are accompanied by chest pain, seek immediate medical attention.
Causes
Most causes of heat intolerance are hereditary in nature, and can begin occurring to some degree in childhood or adolescence. Other causes of heat intolerance include medications such as amphetamines, consuming excess caffeine, pregnancy, menopause and hyperthyroidism, or an overactive thyroid. To pinpoint the cause and establish the correct diagnosis, your physician may ask you questions about your heat intolerance and dizziness, such as if it only occurs before exercise, during or after. He may also ask if your symptoms occur occasionally or only when you exercise, and if symptoms persist in cooler weather or only elevated temperatures.
Treatment
If your heat intolerance occurs in high heat conditions and you have been exercising while having high body temperatures, you are setting yourself up for a possible heat illness. This can be serious, as it may include heat exhaustion or heat stroke in which the body temperature rises above 106 degrees F rather quickly. If this is the case, bring your core body temperature down by moving to a cooler environment, drinking plenty of fluids or seeking emergency medical attention.
Most cases of mild heat intolerance can be treated by relaxing, moving to a cool location, cooling the body temperature with ice packs and placing your head between your legs until feelings of dizziness subside.
Prevention
Avoid heat intolerance and dizziness during exercise by drinking plenty of water or sports drinks to keep you hydrated as you lose body fluid. Dehydration can lead to dizziness and rapid heart rate, so make sure you bring along enough fluid for your entire exercise program. Wear cool, loose clothing, and do not purposely overheat your body by wearing multiple layers. Choose a cool location to work out in, such as an air-conditioned room, or run or jog early in the morning or early in the evening when temperatures are cooler.
