From Dr. Mercola:
According to the Centers for Disease Control and Prevention (CDC), on average, extreme heat causes 658 deaths in the U.S. each year. This is more than those in tornadoes, hurricanes, floods and lightning combined.1 Sadly, many, if not all, of these deaths are preventable.
Occupational Safety and Health Administration (OSHA) reported 2,630 heat illnesses in 2014. These included all conditions related to overheating, such as rhabdomyolysis, heat cramps, heat exhaustion and heat stroke.2
In a study released by the CDC in 2013, researchers found 7,233 heat-related deaths in the U.S. between 1999 and 2009. This data also indicates the numbers are rising.3
In a two-week period in 2012, excessive heat resulted in 32 deaths over four states in the U.S. This is four times the typical average for those same states for the same two-week period between 1999 and 2009.
Just under 70 percent of deaths happen at home and 91 percent of those homes did not have air conditioning. Most of the people who died were either unmarried or living alone.
Factors Affecting Your Potential Risk for Heat Stress
Factors that affect your risk for suffering heat stress include your environment, your work and rest schedules, and your nutrition and training schedules.4 You are most prone to suffering heat stress if you are elderly, have high blood pressure or work or exercise in a hot environment.5
You might think you can only suffer heat stress when temperatures outside are very warm, but it need only be 57 degrees Fahrenheit (13.8 degrees Celsius) to suffer the effects of heat stress.
Humidity is another environmental factor affecting your body’s ability to evaporate sweat, and cool your core temperature. Days of high humidity reduce sweat evaporation, and therefore affect your body’s cooling system. Wind speed will help evaporate sweat and cool your body.
Acclimating to extreme heat is important if you plan to spend time outside working. In this process, you physically adjust to the temperature in your outdoor environment. In a healthy person, this can take up to two weeks; a little faster in the heat and slower in the cold.6
Your physical condition, age and weight are all factors in how quickly you acclimate to your environment. However, this is effective only when you have access to cooling off in times of heat stress. You cannot acclimate to living in an apartment without air conditioning during high temperatures.
Age, medications and metabolic rate are also factors impacting your response to heat.7 As you age, your body’s response to temperature change is reduced, causing higher risk in elderly individuals. Some medications may also interfere with your brain’s temperature regulation.
If your metabolic rate is high, you may feel warm at 72 degrees F (22.2 degrees C), whereas someone with a slow rate will feel cool. How often you rest in the heat, seek a cooler environment and schedule water breaks will also affect your response.
Mild to Moderate Heat Stress
There are varying degrees of heat