BY Rebecca White-Martin
Human bodies dissipate heat by varying the rate and depth of blood circulation, by losing water through the skin and sweat glands,and as a last resort—by panting, when blood is heated above 98.6 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 slows 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 90 degrees) and high relative humidity, the body is doing everything it can to maintain 98.6 degrees inside. The heart is pumping a lot 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.
One of the biggest weather hazards that affects our region during the summer is heat. Many people do not realize how deadly heat can be. In contrast to the visible, destructive, and violent nature of floods and tornadoes, heat is a “silent killer”. The Center for Disease Control (CDC) reports that an average of 350 people die each year due to the effects of heat.
A heat wave is a period of excessive heat lasting 2 days or more that can lead to illnesses in people with prolonged exposure to these conditions. High humidity, which often accompanies heat in our region, can make the effects of heat even more harmful.
While heat related illnesses and death can occur with exposure to heat in just one
afternoon, heat stress on the body does have a cumulative effect.
How the National Weather Service alerts you to extreme heat conditions:
The National Weather Service in Paducah will highlight heat indices at or above 100 degrees in its forecasts. Whenever the heat index is forecast to be at least 105
degrees, a Heat Advisory will be issued.
Whenever the heat index is forecast to be at least 110 degrees for at least 2 days, an Excessive Heat Warning will be issued.
The National Weather Service, as part of its mission for protecting life and property, has a measure of how the hot weather “feels” to the body. This table uses relative
humidity and temperature to produce the “apparent temperature” or the temperature the
body “feels” or what we call the Heat Index value. These values are for shady locations only.
Exposure to full sunshine can increase heat index values by up to 15°F. Also, strong winds, particularly with very hot, dry air, can be extremely hazardous as the wind adds heat to the body. The Heat Index Chart is below.
Heat Wave Safety Tips
– Slow down. Strenuous activities should be reduced, eliminated, or rescheduled to the
coolest time of the day. Individuals at risk should stay in the coolest available place, not necessarily indoors.
– Dress for summer. Lightweight light-colored clothing reflects heat and sunlight, and helps your body maintain normal temperatures.
– Cover all exposed skin with a high SPF sun screen, and wear a wide brimmed hat to protect your face and head.
– Drink plenty of water or other non-alcoholic fluids. Drink plenty of fluids even if you don’t feel thirsty. Avoid coffee and tea because they contain caffeine, which increases water loss through urination. Alcoholic drinks also dehydrate by increasing urination. Soda and fruit juices contain more sugar than needed, so they aren’t absorbed as easily or quickly as water or commercial sports drinks. Eat frequent small, lower protein meals (fruits, vegetables & salads).
– Spend more time in air conditioned places. Air conditioning in homes and other buildings markedly reduces danger from the heat. If you cannot afford an air conditioner, spending some time each day (during hot weather) in an air conditioned environment affords some protection. Keep your electric fans running.
– Don’t get too much sun. Sunburn makes the job of heat dissipation that much more difficult.
– Check on the elderly, infants, young children and people with chronic health problems or disabilities. They are more vulnerable to the effects of heat.
– Keep pets indoors, or provide them with shade and plenty of cool water. Refill their water bowls frequently.
– Do not leave pets, or anyone else, in a closed, parked vehicle.
The above information is opinion based except where noted. Always contact a licensed professional for information on the above subject or BEFORE applying or practicing the above information.
HealthyMartin.com is designed to assist you in finding medical doctors, dentists and alternative, organic & holistic health, fitness and sports professionals in the Treasure Coast Florida areas of Martin County, Palm Beach County, Saint Lucie County and Indian River County. “Healthy Martin, working together for better health choices for you, your family and friends”.