How to be Cool 22 July 2015

If you’re an adolescent, either because of your age or permanent attitudinal persuasion, you probably think I mean how to be suave, debonair, in vogue or pushing the limits of dress standards and attitude, along with maintaining a particular mindset.

It means walking, dressing and grooming to fit in with other cool people who are not square (no longer the definition of a four-sided rectangle with equal length sides) or nerdy. Nope. I mean cool as in not hot. Whups! Hot also refers to sexual attraction in our society. I can’t win! Funny – or sad and strange – how word meanings have changed.

Anyway, I mean cool as in not being overheated in temperature. For the past week or so, instead of complaining of perpetual clouds and never-ending rain, we’ve shifted into the “man, is it hot today” mode. As I write this it’s 92 degrees outside with 50% humidity. Hot and sticky. Temperatures are expected to be in the mid to upper 90s for a week or longer.

Unclothed (“neck-ed”) people are only comfortable in a temperature range of 75-85 degrees, depending on the relative humidity. But we don’t see many necked people around the streets unless they have a serious problem. We modify our temperature by adding or deleting clothing, finding shelter, staying in the shade and using fans or air conditioning. In effect, we modify our environment through technology.

Our bodies also have a built-in temperature regulation system called perspiration that many animals and plants don’t have. We sweat – or perspire if that word’s too coarse. Tiny glands in our skin release water on our surface that evaporates, cooling us. The only problem with that is that on humid days, sweat doesn’t evaporate as quickly or cool as well as it would if the air was drier.

Working outdoors on these hot days can be very dangerous. We sweat profusely and can easily become dehydrated. It can require drinking up to two gallons of water a day to offset our sweat loss and avoid heat stroke or exhaustion. Excessive sweating during work or exercise also causes us to lose electrolytes – sodium and potassium. There are various liquid electrolyte replacers on the market to offset this loss. But you probably don’t need them unless you are running a marathon or working extremely hard. Our bodies cling tenaciously to sodium and potassium. Drinking plenty of plain water is probably enough.

Not many years ago we cooled off in our homes using evaporative coolers that trickled water through fiber layers, and a fan pulled outside air through the wet pads of excelsior-like material, cooling it. People used to call them “swamp coolers.” They helped quite a bit, but not as well as the refrigerated air conditioners that draw air over their very cold coils.

Many animals don’t have the luxury of evaporative cooling by perspiration. They don’t have sweat glands. Maybe that’s alright. Can you visualize a sweaty, slimy snake! Snakes and lizards regulate their temperature by staying in the shade or hiding in damp, cool places when it’s too hot. If they become overheated heat stroke can kill them. When they get too cool they come out in the sun.

Dogs and cats cool off by panting, losing heat from their moist tongues, lungs, and feet. Animals that live in very hot places like deserts have evolved to have long gangly legs, ears, and bodies that radiate heat and help them stay cool. Snowshoe hares living in cold places have short legs and stubby bodies to reduce their surface areas and stay warm. They also grow a fine, fur undercoat of insulation during the winter. So do cats and dogs. If you have one, you know the fun of them shedding fur all over the place in the spring when the undercoat falls out.

Elephants have very large ears with blood vessels close to the surface, designed to help them lose excess body heat from their otherwise bulky bodies. Flapping their ears like fans helps to increase cooling.

Even plants have adaptations that help them control or cope with the heat. Some swivel their leaves around edge-on to the sun to reduce exposure. Cactuses have thick pads with waterproof surfaces to store water. Other plants have a wax-like “skin” on their leaves that reduces water loss.

For you and me the keys are simple and common sense. Try to limit physical labor to morning or evening when it’s cooler, stay in the shade, wear loose, lightweight, light-colored clothing, drink plenty of water even if you don’t feel thirsty, and don’t over exert. You’ll live longer to enjoy our beautiful fields and forests in all kinds of weather.

Dr. Risk is a professor emeritus in the College of Forestry and Agriculture at Stephen F. Austin State University in Nacogdoches, Texas. Content © Paul H. Risk, Ph.D. All rights reserved, except where otherwise noted. Click to send questions, comments, or request permission for use.