It is Throwback Thursday, so I have picked a post about surviving the extreme heat of summer. This post originally appeared on May 19, 2010.
Summer is upon us, and with it comes fun in the sun and time spent playing at the beach, in the woods or at a local sports field. However, with the summertime sun the dangers of exposure to extreme heat are also prevalent.
Survival in extreme heat is a skill that everyone should have. It does not take much for anyone from any walk of life to suddenly be in a dire situation. Succumbing to the dangers of high temperatures is not just for those stranded in the desert or lost in a steamy jungle. Whether you find yourself stranded on a sun-baked highway or stuck in a heat wave, this guide will help you survive the extreme heat.
Extreme Heat is Deadly
Heat waves have some of the highest mortality rates of all weather phenomenons. The CDC reports that, between 1979 and 1999, there were 8,015 heat-related deaths in the United States alone. When severe weather strikes, it often leaves thousands, or even millions, without the power to run air conditioning or fans. In 1995, a heat wave killed about 600 people in Chicago in only 5 days. As recently as 2003, a heat wave in Europe killed more than 52,000. In the aftermath of Hurricane Katrina, many people who survived the hurricane succumbed to the suffocating heat and humidity.
The leading causes of death in the Chicago and European heat wave were poor air circulation and a lack of air conditioning. Some residents in Chicago decided not to open their windows at night for fear of crime. Other residents decided not to run fans or air conditioning because of the increased cost of power. Those decisions ultimately—and unfortunately—led to death in some cases.
There are three things to consider when you need to survive in an extremely hot environment: water, shade and activity level. Failure to take any one of those into account can result in a dire situation very quickly.
Planning Activity Levels
Development of a buddy system is crucial to ensure the elderly and infirmed get care during a heat wave. Buddy systems are also a good way to keep yourself safe. Often the victims of heat illness do not realize they are succumbing to the heat because of the effect it has on the brain. With a buddy, you can keep watch on each other, so you have a second set of eyes watching for possible symptoms of heat stress. Before being in an extreme heat situation, you should have a plan for what to do when faced with the problems that severe heat brings. Begin by taking an inventory of the tools, equipment and materials to which you have access. Address the needs for shade and water first, then focus on ways to set up an air-flow or other cooling system. Include in your plan a schedule for when to engage in any physical activity at times when heat will have a minimal impact.
Plan to curtail outdoor activity, and limit indoor activity to cool areas. All activity raises your body temperature. The more vigorous the activity, the faster and higher your temperature rises and the more your body must work to keep cool. If you must engage in outdoor activity in the heat, limit your work to the early morning hours when it is the coolest. While walking or working in the heat, breathe through your nose, and keep conversation to a minimum to reduce moisture loss through respiration.
One of the best defenses for high heat is hydration. The human body requires water to function, and sweating in high heat depletes that water supply. In extreme heat, it is possible to lose as much of 2.5 liters of sweat per hour. Hydration is key to replenishing the lost water and electrolytes. Dehydration makes it more difficult for your body to stay cool. Hydration not only is necessary for sweat, but it also helps regulate body temperature by making it more difficult for the body to heat up rapidly. Heating up a liter of water just one degree requires almost 4,000 BTUs (British Thermal Units). If your body is missing those 2.5 liters of water, it is that much easier for the heat to raise your body temperature, and your body will need to sweat that much more to keep you cool.
Drink water when you are thirsty. Going without water in to conserve supplies may seem like a good idea, but because of water’s importance in maintaining body temperature, you should always drink when thirsty to maintain hydration. If you find yourself running low on water, seek other sources. You should not ration water in an extremely hot environment. As you become dehydrated, the risk of overheating increases exponentially. Hydration backpacks are a convenient way to carry as much as 3 liters of water.
Maintaining a proper electrolyte balance is as important as proper hydration. When sodium levels in blood plasma are too low, a condition called hyponatremia can lead to coma or death. Symptoms may include nausea, vomiting and headache, although most victims show no symptoms before slipping into a coma. Hyponatremia can occur through the loss of electrolytes through sweat or through the over consumption of water, known as water intoxication. Hyponatremia can strike when you sweat profusely and do not replenish lost electrolytes. For that reason, when in an extremely hot environment, always remember to replenish electrolytes when you hydrate. A teaspoon of salt per quart of water is all you need to keep the right balance of sodium in your blood plasma. A healthy adult can process up to 15 liters of water per day. The important thing to remember when hydrating is to drink over a period of time, not all at once. To prevent hyponatremia from excess water consumption, make sure you consume no more than a half liter of water every 15 minutes.
Plan to have at least one gallon of water per person per day for drinking, but do not neglect the cooling properties of water. Pools, cold showers, baths or even lakes and streams are important resources to use in the heat.
Shade and Shelter
Shade or shelter is extremely important to protect you from the sun’s radiant heat. Intense solar radiation can heat up your body to a higher temperature even when the air temperature is not that high. Because of that, shade is key to keeping cool. When considering shelter construction in an emergency, try to keep your shelter elevated at least 12 inches above the ground. The sun’s rays can heat up the ground as much as 30 degrees hotter than the ambient air temperature. Even resting in the shade on a stool or branch will keep you cooler than sitting on the ground. When outside in direct sunlight, wear a light-colored, wide-brimmed hat or use a scarf and a loose-fitting, long-sleeved, light-colored shirt and pants. If the heat is still too much, soak the scarf or hat in water. The water will cool your skin and evaporate the same way sweat does. By keeping your skin temperature below 92 degrees, you will minimize sweating and the moisture loss associated with it.
Air conditioning is the easiest way to stay cool in the heat, but if you do not have air conditioning, you will need to take other measures. Consider going to public areas with air conditioning if they are available. During heat emergencies, most municipalities make public facilities, such as libraries, community centers, or sporting arenas, available for the public to use as refuge.
Even if air conditioning is not available, it is important to have airflow from fans or some other source. Air circulation is vital to help the body stay cool. When your body becomes overheated, it opens up capillaries near the surface of the skin and sends a message to sweat glands, signaling them to release sweat. The sweat evaporates into the air, and that evaporative cooling effect reduces the temperature of the skin as well as the blood in capillaries near the skin. Your cooler blood will circulate throughout the body and maintain a proper body temperature. Without air circulation, however, the sweat cannot evaporate as easily. Stagnant air makes evaporative cooling from sweat less efficient. While you do not want high wind, some airflow is necessary to maximize the cooling efficiency of sweat. A high wind in a hot environment acts as a convective oven, increasing the heating effect and dehydration.
If you are indoors and have electricity but no air conditioning, keep windows closed in the morning and use fans for airflow. The radiant heat from the sun rapidly heats up the air outdoors; however, a building’s insulation will keep it cooler than the outside air. As the day heats up, it will be necessary to open windows to move hot, stagnant air out and allow breezes to cool the indoors. By opening windows on the windward side of the structure as well as the leeward, you can create a cross-flow of air through the building.
If you have the equipment, you can set up an evaporative cooling system. The tiny water droplets from swamp coolers or fan-powered misting systems quickly evaporate into the air, causing a 15-20 degree drop in temperature. Though sold commercially, qualified people can build an evaporative cooler with a fan and a few plumbing parts. Always exercise caution when working around water and electricity.
Surviving Extreme Heat
If you have a plan for the situation, you will find yourself at an enormous advantage and will be better able to beat the heat. By staying cool and hydrated in the shade and planning your activities around the hottest parts of the day, you can endure even the worst heat that Mother Nature can muster.
How do you beat the heat? Share your tips in the comment section.