Excess Heat

Extreme heat and high humidity can be very dangerous and even life-threatening if you don’t take the proper preventive actions. People suffer heat-related illness when their bodies are unable to compensate to high temperatures and properly cool themselves. The body normally cools itself by sweating. But under some conditions, sweating just isn’t enough. In such cases, a person’s body temperature rises rapidly. Risk factors for excess heat include age, obesity, fever, dehydration, heart disease, mental illness, poor circulation, sunburn, and prescription drug and alcohol use.¹

• Historically, from 1979-2003, excessive heat exposure caused 8,015 deaths in the United States. During this period, more people in this country died from extreme heat than from hurricanes, lightning, tornadoes, floods, and earthquakes combined.¹
• Elderly people (65 years and older), infants and children and people with chronic medical conditions are more prone to heat stress.¹
• People living in urban areas may be at greater risk from the effects of a prolonged heat wave than those living in rural areas due to stagnant atmospheric conditions and poor air quality in cities. Also, asphalt and concrete store heat longer and gradually release heat at night, which can produce higher nighttime temperatures known as the “urban heat island effect.”²
• Air-conditioning is the number one protective factor against heat-related illness and death.¹

High heat and humidity can cause several heat-related illnesses as a person’s body temperature rises. Very high body temperatures may damage the brain or other vital organs.¹

• Heat stroke occurs when the body is unable to regulate its temperature. When the body’s temperature rises quickly it is unable to sweat properly and can’t cool down. Body temperature may rise to 106°F or higher within 10 to 15 minutes. Heat stroke can cause death or permanent disability if emergency treatment is not provided. Warning signs of heat stroke may include:¹
  • An extremely high body temperature (above 103°F, orally)
  • Red, hot, and dry skin (no sweating)
  • Rapid, strong pulse
  • Throbbing headache
  • Dizziness
  • Nausea
  • Confusion
  • Unconsciousness

• Heat exhaustion is a milder form of heat-related illness that can develop after several days of exposure to high temperatures and inadequate or unbalanced replacement of fluids. It is the body’s response to an excessive loss of the water and salt contained in sweat. Those most prone to heat exhaustion are elderly people, people with high blood pressure, and people working or exercising in a hot environment. If heat exhaustion is untreated, it may progress to heat stroke. Seek medical attention immediately if symptoms are severe or the victim has heart problems or high blood pressure. Otherwise, help the victim to cool off, and seek medical attention if symptoms worsen or last longer than 1 hour. Warning signs of heat exhaustion include:¹
  • Heavy sweating
  • Paleness
  • Muscle cramps
  • Tiredness
  • Weakness
  • Dizziness
  • Headache
  • Nausea or vomiting
  • Fainting
  • The skin may be cool and moist. The victim’s pulse rate will be fast and weak, and breathing will be fast and shallow.¹

• Heat rash is a skin irritation caused by excessive sweating during hot, humid weather. It can occur at any age but is most common in young children. Heat rash looks like a red cluster of pimples or small blisters. It is more likely to occur on the neck and upper chest, in the groin, under the breasts, and in elbow creases.

To help prevent health and safety risks due to excess heat, see below for suggested actions you can take²:

• Install window air conditioners snugly; insulate if necessary. Check air-conditioning ducts for proper insulation.
• Weather-strip doors and sills to keep cool air in.
• Cover windows that receive morning or afternoon sun with drapes, shades, awnings, or louvers. (Outdoor awnings or louvers can reduce the heat that enters a home by up to 80 percent.)
• Never leave children or pets alone in closed vehicles.
• Stay indoors as much as possible and limit exposure to the sun.
• Stay on the lowest floor out of the sunshine if air conditioning is not available.
• Consider spending the warmest part of the day in public buildings such as libraries, schools, movie theaters, shopping malls, and other community facilities. Circulating air can cool the body by increasing the perspiration rate of evaporation.
• Drink plenty of water; even if you do not feel thirsty. Avoid drinks with caffeine. Persons who have epilepsy or heart, kidney, or liver disease; are on fluid-restricted diets; or have a problem with fluid retention should consult a doctor before increasing liquid intake.
• Dress in loose-fitting, lightweight, and light-colored clothes that cover as much skin as possible. Avoid dark colors because they absorb the sun’s rays. Protect face and head by wearing a wide-brimmed hat.

For contact information of partner organizations that might be able to provide help with excess heat hazards in your home, visit our Get Help page.

¹Centers for Disease Control and Prevention: Extreme Heat: A Prevention Guide to Promote Your Personal Health and Safety (http://emergency.cdc.gov/disasters/extremeheat/heat_guide.asp)
²Ready.gov: Extreme Heat (http://www.ready.gov/heat
³U.S. Department of Housing & Urban Development: Healthy Home Rating System – Operating Guidance (http://portal.hud.gov/hudportal/documents/huddoc?id=operating_guidance_hhrs_v1.pdf)