Heat-related illnesses and injuries are the most frequent cause of environmentally related death in the United States, resulting in over 400 deaths annually. Risk factors include dehydration from a lack of water consumption, obesity, and certain medications. Minor heat injuries include heat rash and heat cramps. Moderate heat injury is heat exhaustion, while major heat injury is the life-threatening heat stroke with a core temperature over 104°F. Prevention focuses on proper hydration, limiting outdoor activity during peak heat hours, and recognizing symptoms to promptly treat potential illnesses or injuries.

1. Heat Related Illness
and Injuries
John W. Lyng, MD, FACEP, NREMT-P
Medical Director, Office of the Medical Directors
North Memorial Ambulance & Air Care
Emergency Physician, Dept. of Emergency Medicine
North Memorial Medical Center

2. Heat Related Illness and Injuries
Most frequent cause of environmentally related death
 More than lightning, tornado, hurricane, flood, cold, and
winter-related fatalities
Incidence:
 ~ 1 per 1 million for 5-44 y/o
 ~ 5 per 1 million for >85 y/o
 Males and females are equally affected
~400 deaths annually (about 8 per state!!)
 Risk of death from Heat Stroke 10-75%, and increases if
treatment is delayed >2 hours after onset of severe symptoms
~60,000 cases seek medical attention each year in the US

3. Risk Factors
Not drinking enough water
 Dehydration
 Results in decreased ability to cool the body by sweating
 Each 1% decrease in body weight due to dehydration can = a core
temp increase of 0.2-0.5°F
 Athletes voluntarily drink only 50% of volume lost via sweating
Obesity
Constant exposure to heat without air conditioning or night
cooling
Certain medications used to treat high blood pressure, heart
conditions, and fluid retention in the legs

5. Minor Heat Injury
 Heat Edema, Heat Rash
(Prickly heat)
 Heat Cramps
 Due to deficiency in
electrolytes and fluids
 Heat Fainting
 Dizziness when sitting or
standing
 Does not represent
significant dehydration
 Treat with fluids, rest, and
removal from hot
environments

6. Moderate Heat Injury: Heat Exhaustion
Significant dehydration
 Weakness, lightheadedness, dizzyness, nausea, vomiting,
headache, muscle aches
Fast pulse, fast breathing, sweating, fainting
Core temperature from normal (98.6°F) to 104°F
Mental Status is NORMAL
 Treat with fluids, rest, and removal from the hot
environment

7. Major Heat Injury: Heat Stroke
Mental Status Change (confusion, disorientation,
lethargy, unconsciousness)
Core temp >104°F
Lack of sweating is present in about 50% of cases
Represents complete breakdown of the body’s ability to
regulate its temperature
Primary cause is increased heat production but can be
related to inability to escape excessively hot
environments

8. Heat Illness: Prevention
 Ensure adequate hydration with water
 For every 2 bottles of water
drink 1 bottle of sports beverage
 Avoid energy drinks, pop/soda, and other beverages
that contain caffeine
 Schedule sports practices, games, yardwork
and other outdoor physical activities
during cooler times of day
 Provide shade
 Provide cooling/misting fans
 Take frequent heat breaks
 Encourage use of sunscreen

9. If you suspect someone is suffering from aIf you suspect someone is suffering from a
heat-related injury or illness:heat-related injury or illness:
Call 911
Remove the victim from the hot environment if possible
Loosen and/or remove clothing
Spray the victim with with room temperature water and
use a fan to blow air across the victim’s body
Apply cold packs to the groin, neck, and armpits
Do not fully immerse in cold water

10. You can prevent dangerous injuries andYou can prevent dangerous injuries and
illness from excessive heat:illness from excessive heat:
Do not allow children or pets to sit in any motor vehicle
unattended for any period of time
Check in on older adults to ensure they have access to a
cool environment
Drink plenty of fluids
Limit consumption of caffeine and alcohol
Make sure pets have access to plenty of fresh water and
shade
Avoid outdoor activities during the hottest part of the
day