Clothing for Hot Weather
The first thing that should be said about outdoor clothing for hot weather is that it should be comfortable. Secondly, a healthy body requires a steady temperature of around 37°C (98.6°F) through the dynamic balance of heat production from muscle work, and heat loss from sweating. When this balance is upset and the body can no longer cool or warm itself properly, a number of heat-related health problems may occur.
How Heat Affects the Human Body
Human bodies dissipate heat by varying the rate and depth of blood circulation, by losing water through the skin and sweat glands, and-as the last extremity is reached-by panting, when blood is heated above 37°C (98.6°F) degrees. The heart begins to pump more blood, blood vessels dilate to accommodate the increased flow, and the bundles of tiny capillaries threading through the upper layers of skin are put into operation.
The body’s blood is circulated closer to the skin’s surface, and excess heat drains off into the cooler atmosphere. At the same time, water diffuses through the skin as perspiration. The skin handles about 90 percent of the body’s heat dissipating function. Sweating, by itself, does nothing to cool the body, unless the water is removed by evaporation, and high relative humidity retards evaporation.
The evaporation process itself works this way: the heat energy required to evaporate the sweat is extracted from the body, thereby cooling it. Under conditions of high temperature (above 32°C or 90°F)) and high relative humidity, the body is doing everything it can to maintain 37 degrees inside. The heart is pumping a torrent of blood through dilated circulatory vessels; the sweat glands are pouring liquid-including essential dissolved chemicals, like sodium and chloride onto the surface of the skin.
Basic points on outdoor clothing for hot weather:
- Wear desert type caps, with flaps to shade your head, shoulders and neck.
- Wear loose fitting clothing to allow air to circulate to naturally cool you.
- Wear lightweight light-coloured clothing for hot weather that reflects heat and sunlight, which will help your body maintain normal temperatures.
- Walk in the cooler times of the day, such as early morning and toward evening, avoiding searing midday temperatures.
- Drink plenty of water or other non-alcohol fluids. Your body needs water to keep cool. Drink plenty of fluids even if you don’t feel thirsty.
Avoid Getting Skin Cancer!
Sunblock with a SPF of at least 15 is commonly recommended for protecting the skin from the sun’s harmful rays; unfortunately it also blocks the pores of the skin, restricting perspiration and evaporation. When buying clothes for outdoor activities, look for clothing with SPF ratings of at least “SPF 15”. Modern outdoor clothing for hot weather rated at “SPF 30” and “SPF 40” is commonly available. In contrast, an ordinary cotton t-shirt offers an SPF rating of only “SPF 5” to “SPF 9” (and, when damp, much less than that) —well below the minimum “SPF 15” recommended by doctors for even minimal exposure.
If you do not take care in hot conditions and pay attention to your outdoor clothing for hot weather you are simply begging for trouble. Initially, exertion in heat and/or lack of water (or loss of water and salt from heavy sweating) will cause cramps. Heat exhaustion comes next, your body temperature is still normal, but your skin is cold and clammy, you’re thirsty, become uncoordinated and feel dizzy. Finally, there is heat stroke, and If you’ve let things get to this stage, you’re in serious trouble. I been involved in search and rescue operations in Australia’s outback and witnessed sad occasions where people who have died as a result of heatstroke.