OUT INT HE HEAT
How far you are prepared to go this July depends on how well you understand your body in the summer

Humidity
Lots of places in Oman might be dry and hot, but pay special attention to how humid your area might be. Only people who are acclimatised should exercise outside in high heat and humidity, and you’re better off without vigorous activity. So, short and slow type of activities, if any, ought to be conducted at this time of heat stress.

If you have a temperature of 37ºC and humidity of 30 per cent or less, that doesn’t carry with it the same risk of heat stress as having a lower temperature, say 32ºC, with humidity of 60 per cent. There are a lot of unexpected heat problems in situations where the temperature is not that high, but humidity is around 90-100 per cent.

Age
Two age groups that are the most susceptible to heat are the young and the old. One of the problems is that older people just can’t handle the heat stress like they could during their youth. The reason kids absorb more heat from their environment is because they have a higher body mass ratio than adults. The smaller the child, the faster the heat is absorbed. Adults are at danger because there are subtle age-related differences in body fluid balance. Elders must practice a more gradual acclimatisation to heat, with emphasis on hydration, as they are more likely, normally, to be dehydrated. If you add dehydration to excessive heat you are dramatically increasing the risk for heat stress.

Exercise and acclimatisation
Finally, athletes and exercisers who spend a lot of time training and competing in the hot daylight hours typically do not drink enough to match fluid loss. Why? Exercise and activity increases the core body temperatures to a point that your body’s air conditioning or sweat turns on. As sweat evaporates from your skin, it cools the body.

Also, as blood circulates between the skin and hot muscle it helps transfer heat out of the body, keeping your body’s core temperature in the safe zone. When exercising in the heat, your core temperature rises more rapidly, because the warmer air makes it harder to dissipate heat from the body.

Your body adapts to warmer weather, as acclimatisation, by learning to sweat sooner and to sweat more, helps keep the body from reaching dangerous heat levels. By sweating sooner and faster, you lose more fluids than before. This means that dehydration is more likely when you’re acclimatised to heat. Seems strange, but it’s true.

If you do add exercise to heat, you will expend more energy. If you start sweating immediately after starting to exercise, that’s a classic example of being acclimatised to heat. The earlier the onset of sweating and the more you sweat, the less likely you are to suffer heat illness. But remember that men sweat while women glow. Why? Because the core temperature of a woman must be about 1.5 degrees higher than a man before she starts sweating. It may take her longer to acclimatise to heat, and she may be more susceptible to heat illness.

Heart stress
If you exercise in the heat, consider the acceleration of the heart rate that occurs just with heat exposure, and add to that the acceleration of heart rate with exercise. This is called a synergistic effect, or one plus one equals three. That means you get more caloric expenditure, but also much more stress on the heart. That’s the reason that people that have heart disease of any type should avoid vigorous exercise in the heat.

Dressing
The head is a prominent place to lose heat, but also to gain it. You should be much more concerned about the harmful effects of direct sun on the head without a hat than with what you would lose covering the head as far as being able to dissipate heat.

You need to dress as lightly as possible, but you also need to avoid sunburn. If you are going to be exposed longer than 15-20 minutes out of doors, you should use a sunscreen of an SPF rating of at least 20 to 30.

Sometimes, our instinctive reaction to getting out in the sun – wearing as little as possible, is exactly the opposite of what you should do. Think sensibly, and enjoy this summer.