Even sitting in the shade, you're at risk of over-exposure to the fierce tropical sun

Our bodies have the capacity to create a lot of heat, particularly internal heat. We normally cool ourselves by sweating, radiating this heat out through our skin and by our normal breathing. Under some circumstances, such as the unusually high temperatures found in the tropics, coupled with high humidity and vigorous exercise, our natural cooling system may begin to fail, allowing internal heat to build up, sometimes to dangerous levels. This increased heat manifests itself in various forms, from heat rash, heat cramps and heat exhaustion, to the potentially lethal heatstroke.

Heat rash is very common here in Phuket. It’s sometimes referred to as prickly heat, sweat rash or miliaria, and new Phuket residents and visitors may find that they develop this condition, as they become accustomed to the heat and humidity. A rash of red or pink dots is generally found on the body, particularly those areas covered by clothing. The dots can look like pimples. It occurs because the sweat ducts become blocked and swell, which can cause discomfort and itching. The rash areas may get irritated by clothing or scratching, and a skin infection will then occur. Most heat rashes heal themselves without problems, with the use of common treatments readily available from supermarkets and pharmacies. Good personal hygiene is also important. If you think you’ve an infection, you should seek medical advice.

Heat cramps occur in muscles after exercise because sweating causes the body to lose water, salt and minerals (electrolytes). The loss of salt and water affects the exercised muscles, which cramp and become painful. Leg muscles, such as the calf or thigh muscles, are usually the most affected. To prevent heat cramps, drink a rehydration or sports drink, such as Gatorade, or take the readily available ORS solutions that you mix with water. People who are adequately hydrated are less likely to experience heat cramps. It’s incorrect to take salt as this is absorbed slowly and is likely to cause stomach irritation. Taking salt can also aggravate the water loss problem, as it will pull fluid from the tissues into the blood system. If you get heat cramps whilst exercising, you should stop physical activity, gently massage and stretch the affected area. Don’t resume vigorous exercise until the heat cramps have gone, as it’s possible to tear and cause serious injury to muscle and soft tissue.

Many people get swollen hands, feet or ankles when they sit or stand for a long time while in a hot environment. This is referred to as heat edema. Heat causes the blood vessels to dilate, so that body fluid is moved into the hands or legs by gravity. The balance of salt in the body is also a risk factor for heat edema. If salt loss is less than normal, the increased salt level draws fluid by gravity into the hands and legs. Older adults have an increased risk of heat edema, especially if they’ve other medical conditions that affect their circulation. Heat edema is also common in women during pregnancy. The best treatment is to use gravity to put the excessive fluid back into the right places, so elevate your feet. This will reduce the swelling. If the edema becomes excessive, to the extent that it affects your daily activities, or it’s painful to walk, consult your doctor. He may give you some medication to get rid of the extra fluid, and correct any fluid balance problems that may become evident.

Heat exhaustion or sunstroke occurs when a person can’t sweat enough to cool the body. It generally develops when a person is working or exercising in hot weather. Symptoms of heat exhaustion include fatigue, weakness, headache, dizziness, and nausea, and skin that is cool, moist and pale, or flushed. Mild cases of heat exhaustion can be treated at home. Keep cool; air-conditioned spaces are best, and use cold towels and water to cool the body. Applying cold compresses to the head, armpits and groin is most effective.

Heat exhaustion can sometimes lead to heatstroke, which requires emergency treatment. Also known as ‘Core Temperature Emergency’, heat stroke is potentially fatal. In this condition, the body’s temperature regulation centre in the brain has been rendered inoperable, and the temperature continues to rise, causing eventual brain damage. Immediate active intervention is necessary to avoid coma and death. To treat heat stroke, immediate cooling of the body is required. Remove clothing. Use ice packs to the neck, groin and armpits. Cover with a wet sheet and use a fan or air-conditioning if available, and be prepared to resuscitate.

Taking minor precautions, drinking lots of fluid and replacing electrolytes can go a long way in beating the heat, particularly if you exercise. You should also remember that your urine output is a good indication of your hydration status, and as well as preventing kidney stones, drinking lots of fluid is generally good for you. If you’re only urinating every three to five hours, or if your urine smells offensive, or is not a light straw color, you aren’t drinking enough.

Peter Davison is the Manager International Services
at Phuket International Hospital.
Tel: +66 (0)76 249400. Email: info@phuketinternationalhospital.com.