Heat exhaustion and heat stroke are both caused by excessive heat, but they are not the same. Heat exhaustion commonly causes heavy sweating, dizziness, headache, nausea, and weakness. Heat stroke may cause confusion, seizures, loss of consciousness and a very high body temperature.
Heat exhaustion requires immediate cooling and attention. Heat stroke is a life-threatening medical emergency. Call 911 and begin cooling the person immediately.
Knowing the difference between heat exhaustion vs. heat stroke can help you respond appropriately when every minute matters.
What Is the Difference Between Heat Exhaustion and Heat Stroke?
Heat exhaustion occurs when the body loses too much water and salt, usually through heavy sweating. The body is struggling with the heat but can still regulate its temperature.
Heat stroke occurs when the body can no longer control its temperature. Body temperature can rise rapidly, potentially damaging the brain and other organs.
The most important difference is mental status. Someone with heat exhaustion may feel tired, dizzy or sick but generally remains alert. Confusion, slurred speech, seizures, fainting or loss of consciousness may indicate heat stroke and require an immediate call to 911.
Heat Exhaustion at a Glance
Common signs include:
- Heavy sweating
- Dizziness
- Headache
- Nausea
- Weakness
- Thirst
- Muscle cramps
- Cool or clammy skin
Move the person to a cooler area, loosen clothing, begin cooling and provide small sips of water if the person is alert and able to swallow safely.
Heat Stroke at a Glance
Emergency warning signs include:
- Confusion or unusual behavior
- Slurred speech
- Loss of coordination
- Seizures
- Fainting or loss of consciousness
- A very high body temperature
- Hot skin that may be dry or covered in heavy sweat
Call 911 immediately. Move the person to a cooler area and begin cooling while waiting for emergency responders. Do not give fluids to someone who is confused, unconscious, vomiting or unable to swallow safely.
Why Can Arkansas Heat Be Dangerous?
Arkansas summers often combine high temperatures with heavy humidity. Your body normally cools itself through sweating, but humid conditions make it more difficult for sweat to evaporate. That can prevent the body from releasing heat effectively.
Heat-related illness can develop during ordinary summer activities, including:
- Working outside
- Mowing or doing yardwork
- Exercising
- Attending outdoor events
- Visiting a park
- Coaching or watching youth sports
- Spending time without reliable air conditioning
You do not have to spend an entire day outside to become sick. Risk increases with strenuous activity, limited water intake, direct sunlight and extended exposure to hot or humid conditions.
How Can You Prevent Heat-Related Illness?
Most heat-related illnesses are preventable. Planning ahead and responding to early symptoms can reduce the risk of a medical emergency.
Drink Water Regularly
Drink water throughout the day instead of waiting until you feel thirsty. Thirst may not always be an early warning that your body needs more fluids.
People working or exercising outdoors for an extended period may also need to replace electrolytes lost through heavy sweating. For most routine activities, water remains the best choice.
People who have been instructed to limit fluids because of a medical condition should follow their healthcare provider’s recommendations.
Plan Outdoor Activities Carefully
Whenever possible, schedule strenuous outdoor activities during the cooler morning or evening hours.
Take frequent breaks in a shaded or air-conditioned location. Pay attention to local forecasts, heat advisories and the heat index, which describes how hot conditions feel when temperature and humidity are considered together.
Dress for the Heat
Wear lightweight, loose-fitting and light-colored clothing. A wide-brimmed hat can provide additional protection from direct sunlight.
Apply sunscreen to exposed skin. Sunburn can interfere with the body’s ability to cool itself and may contribute to dehydration.
Never Leave Anyone in a Parked Vehicle
Never leave a child, older adult, person with a disability or pet inside a parked vehicle, even for a few minutes. Temperatures inside a vehicle can rise rapidly and become deadly.
Always check the back seat before locking and leaving your vehicle.
What Are the Signs of Heat Exhaustion?
Heat exhaustion is the body’s response to excessive loss of water and salt.
Symptoms may include:
- Heavy sweating
- Headache
- Dizziness or lightheadedness
- Weakness or unusual fatigue
- Nausea or vomiting
- Muscle cramps
- Irritability
- Thirst
- Cool, pale or clammy skin
- An elevated body temperature
- Reduced urination
A person experiencing these symptoms should stop all physical activity immediately.
What Should You Do for Heat Exhaustion?
Move the person to a shaded, cool or air-conditioned location. Loosen or remove unnecessary clothing and begin cooling the body with cold compresses, wet towels or cool water.
Provide frequent small sips of cool water if the person is awake, alert and able to swallow safely. Stay with the person and do not allow a return to strenuous activity that day.
Seek medical care when:
- Symptoms worsen
- Symptoms do not begin improving after cooling
- Symptoms continue for approximately one hour
- The person cannot drink or keep fluids down
- The person has an existing medical condition that increases the risk of complications
Call 911 if the person becomes confused, loses consciousness, experiences a seizure or develops other signs of heat stroke.
What Are the Signs of Heat Stroke?
Heat stroke is the most serious heat-related illness. It occurs when the body can no longer regulate its temperature and requires emergency treatment.
Warning signs may include:
- Confusion or altered behavior
- Slurred speech
- Loss of coordination
- Fainting
- Loss of consciousness
- Seizures
- A very high body temperature
- Hot, dry skin or heavy sweating
- Rapid breathing
- A rapid pulse
A person does not have to stop sweating to have heat stroke. Someone experiencing heat stroke may have dry skin or may continue to sweat heavily.
What Should You Do for Heat Stroke?
Call 911 immediately. Do not wait to see whether the person improves.
While waiting for emergency responders:
- Move the person to a shaded or air-conditioned area.
- Remove unnecessary outer clothing.
- Cool the person with cold water, wet towels or an ice bath when available.
- Place cold, wet cloths or ice packs around the head, neck, underarms and groin.
- Circulate air around the person to increase cooling.
- Stay with the person until help arrives.
Do not force the person to drink. Someone who is confused, unconscious, vomiting or unable to swallow safely could choke.
Who Has a Higher Risk of Heat-Related Illness?
Anyone can develop a heat-related illness, including young and otherwise healthy people. Risk may be higher for:
- Infants and young children
- Adults age 65 and older
- Pregnant individuals
- Outdoor workers
- Athletes
- People without reliable air conditioning
- People with heart disease, diabetes or other chronic conditions
- People taking certain prescription or over-the-counter medications
Some medications may affect sweating, hydration or the body’s ability to regulate temperature. Do not stop taking a medication on your own. Ask a healthcare provider or pharmacist whether you need additional precautions during hot weather.
Check frequently on relatives, friends and neighbors who may have a higher risk, especially during extended periods of extreme heat.
When Should You Contact a Healthcare Provider?
Medical evaluation may be appropriate when symptoms related to dehydration or heat exposure continue, return frequently or involve an existing health condition.
Contact a healthcare provider for concerns including:
- Ongoing dizziness or weakness
- Repeated dehydration
- Persistent nausea or vomiting
- Muscle cramps that do not improve
- Reduced urination
- Questions about how a medical condition affects heat risk
- Questions about medications and hot weather
Healthy Connections provides primary care and preventive services for individuals and families throughout Western and Central Arkansas. Our providers can evaluate symptoms related to dehydration and heat exposure while helping patients manage health conditions that may increase their risk during extreme temperatures.
Heat stroke should not be handled through a routine clinic appointment. Confusion, loss of consciousness, seizures or other signs of heat stroke require an immediate call to 911.
Frequently Asked Questions About Heat Exhaustion and Heat Stroke
Can heat exhaustion turn into heat stroke?
Yes. Heat exhaustion can progress to heat stroke if the person remains in the heat or does not receive prompt cooling and care. Stop physical activity and move the person to a cooler location as soon as symptoms appear.
Should you give water to someone with heat exhaustion?
Small, frequent sips of cool water may be given when the person is awake, alert and able to swallow safely. Do not give fluids to someone who is confused, unconscious, vomiting or unable to swallow.
How long does heat exhaustion last?
Symptoms should begin improving after the person moves to a cooler location, rests, drinks fluids and begins cooling. Seek medical care if symptoms worsen, do not begin improving or continue for approximately one hour.
When should you call 911 for a heat-related illness?
Call 911 for confusion, slurred speech, seizures, loss of consciousness, a very high body temperature or other signs of heat stroke. Begin cooling the person immediately while waiting for emergency responders.
Protect Yourself During the Arkansas Summer
Understanding heat exhaustion vs. heat stroke can help you recognize warning signs and make the right decision quickly. Drink water regularly, limit strenuous activity during the hottest part of the day, take cooling breaks and pay attention when your body tells you something is wrong.
For concerns about ongoing symptoms from heat exposure or help managing a condition that may increase your risk, call Healthy Connections at 888-710-8220 or visit healthy-connections.org.