Heat emergencies
Heatstroke; Heat illness
Heat emergencies or illnesses are caused by exposure to extreme heat and sun. Heat illnesses can be prevented by being careful in hot, humid weather.
Causes
Heat injuries can occur due to high temperatures and humidity. You are more likely to feel the effects of heat sooner if:
- You are not used to high temperatures or high humidity.
- You are a child or an older adult.
- You are already ill from another cause or have been injured.
- You are obese.
- You are also exercising. Even a person who is in good shape can suffer heat illness if warning signs are ignored.
The following make it harder for the body to regulate its temperature, and make a heat emergency more likely:
- Drinking alcohol before or during exposure to heat or high humidity
- Not drinking enough fluids when you're active on warmer or hot days
- Heart disease
- Certain medicines: Examples are beta-blockers, water pills or diuretics, some medicines used to treat depression, psychosis, or ADHD
- Sweat gland problems
- Wearing too much clothing
Symptoms
Heat cramps are the first stage of heat illness. If these symptoms are not treated, it can lead to heat exhaustion and then heat stroke.
Heat stroke occurs when the body is no longer able to regulate its temperature, and it keeps rising. Heat stroke can cause shock, brain damage, organ failure, and even death.
The early symptoms of heat cramps include:
-
Muscle cramps
and pains that most often occur in the legs or abdomen
Muscle cramps
Muscle cramps are when a muscle gets tight (contracts) without you trying to tighten it, and it does not relax. Cramps may involve all or part of on...
-
Very heavy sweating
Very heavy sweating
Sweating is the release of liquid from the body's sweat glands. This liquid contains salt. This process is also called perspiration. Sweating helps...
-
Fatigue
Fatigue
Fatigue is a feeling of weariness, tiredness, or lack of energy.
-
Thirst
Thirst
Excessive thirst is an abnormal feeling of always needing to drink fluids.
Later symptoms of heat exhaustion include:
-
Headache
Headache
A headache is pain or discomfort in the head, scalp, or neck. Serious causes of headaches are rare. Most people with headaches can feel much better...
-
Dizziness
,
lightheadedness
Dizziness
Dizziness is a term that is often used to describe 2 different symptoms: lightheadedness and vertigo. Lightheadedness is a feeling that you might fai...
Lightheadedness
Fainting is a brief loss of consciousness due to a drop in blood flow to the brain. The episode most often lasts less than a couple of minutes and y...
- Weakness
-
Nausea and vomiting
Nausea and vomiting
Nausea is feeling an urge to vomit. It is often called "being sick to your stomach. "Vomiting or throwing-up is forcing the contents of the stomach ...
- Cool, moist skin
-
Dark urine
Dark urine
Blood in your urine is called hematuria. The amount may be very small and only detected with urine tests or under a microscope. In other cases, the...
The symptoms of heatstroke include (call 911 or the local emergency number right away):
- Fever -- temperature above 104°F (40°C)
- Irrational behavior
- Extreme confusion
- Dry, hot, and red skin
-
Rapid, shallow breathing
Rapid, shallow breathing
Breathing difficulty may involve:Difficult breathingUncomfortable breathingFeeling like you are not getting enough air
- Rapid, weak pulse
-
Seizures
Seizures
A seizure is the physical findings or changes in behavior that occur after an episode of abnormal electrical activity in the brain. The term "seizure...
-
Unconsciousness
Unconsciousness
Unconsciousness is when a person is unable to respond to people and activities. Doctors often call this a coma or being in a comatose state. Other c...
First Aid
If you think a person may have heat illness or emergency:
- Have the person lie down in a cool place. Raise the person's feet about 12 inches (30 centimeters).
- Apply cool, wet cloths (or cool water directly) to the person's skin and use a fan to lower body temperature. Place cold compresses on the person's neck, groin, and armpits.
- If alert, give the person a beverage to sip (such as a sports drink), or make a salted drink by adding a teaspoon (6 grams) of salt per quart (1 liter) of water. Give a half cup (120 milliliters) every 15 minutes. Cool water will do if salt beverages are not available.
-
For
muscle cramps
, give beverages as noted above and massage affected muscles gently, but firmly, until they relax.
Muscle cramps
Muscle cramps are when a muscle gets tight (contracts) without you trying to tighten it, and it does not relax. Cramps may involve all or part of on...
-
If the person shows signs of
shock
(
bluish lips and fingernails
and
decreased alertness
), starts having
seizures
, or loses consciousness, call 911 and give first aid as needed.
Shock
Shock is a life-threatening condition that occurs when the body is not getting enough blood flow. Lack of blood flow means that the cells and organs...
Bluish lips and fingernails
Cyanosis is a bluish color to the skin or mucous membrane that is usually due to a lack of oxygen in the blood.
Decreased alertness
Decreased alertness is a state of reduced awareness. A coma is a state of decreased alertness from which a person cannot be awakened. A long-term co...
Seizures
A seizure is the physical findings or changes in behavior that occur after an episode of abnormal electrical activity in the brain. The term "seizure...
Do Not
Follow these precautions:
- Do NOT give the person medications that are used to treat fever (such as aspirin or acetaminophen). They will not help, and they may be harmful.
- Do NOT give the person salt tablets.
- Do NOT give the person liquids that contain alcohol or caffeine. They will make it harder for the body to control its internal temperature.
- Do NOT use alcohol rubs on the person's skin.
- Do NOT give the person anything by mouth (not even salted drinks) if the person is vomiting or unconscious.
When to Contact a Medical Professional
Call 911 if:
- The person loses consciousness at any time.
- There is any other change in the person's alertness (for example, confusion or seizures).
- The person has a fever over 102°F (38.9°C).
- Other symptoms of heatstroke are present (like rapid pulse or rapid breathing).
- The person's condition does not improve, or worsens despite treatment.
Prevention
The first step in preventing heat illnesses is thinking ahead.
- Find out what the temperature will be for the whole day when you will be outdoors.
- Think about how you have dealt with heat in the past.
- Make sure you will have plenty of fluids to drink.
- Find out if there is shade available where you are going.
- Learn the early signs of heat illness.
To help prevent heat illnesses:
- Wear loose-fitting, lightweight and light-colored clothing in hot weather.
- Rest often and seek shade when possible.
- Avoid exercise or heavy physical activity outdoors during hot or humid weather.
- Drink plenty of fluids every day. Drink more fluids before, during, and after physical activity.
- Be very careful to avoid overheating if you are taking drugs that impair heat regulation, or if you are overweight or elderly.
- Be careful of hot cars in the summer. Allow the car to cool off before getting in.
- NEVER leave a child sitting in a car exposed to the hot sun, even after opening windows.
References
Platt M, Vicario S. Heat illness. In: Marx JA, Hockberger RS, Walls RM, et al, eds. Rosen's Emergency Medicine: Concepts and Clinical Practice . 8th ed. Philadelphia, PA: Elsevier Saunders; 2014:chap 141.
Sawka MN, O'Connor FG. Disorders due to heat and cold. In: Goldman L, Schafer AI, eds. Goldman's Cecil Medicine . 25th ed. Philadelphia, PA: Elsevier Saunders; 2016:chap 109.
-
Heat emergencies - illustration
Heat emergencies are of three types: heat cramps (caused by loss of salt), heat exhaustion (caused by dehydration) and heat stroke (shock). Remove the victim from the heat and have him lie down. Apply cool compresses, elevate the feet, drink fluids and use a fan to blow cool air. Get medical help if needed.
Heat emergencies
illustration
-
Heat emergencies - illustration
Heat emergencies are of three types: heat cramps (caused by loss of salt), heat exhaustion (caused by dehydration) and heat stroke (shock). Remove the victim from the heat and have him lie down. Apply cool compresses, elevate the feet, drink fluids and use a fan to blow cool air. Get medical help if needed.
Heat emergencies
illustration
Review Date: 11/4/2015
Reviewed By: Jesse Borke, MD, FACEP, FAAEM, Attending Physician at FDR Medical Services/Millard Fillmore Suburban Hospital, Buffalo, NY. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.