Medically reviewed by David Moore, MD
Most people think of heat stroke as something that happens to other people, like marathon runners in extreme conditions, or someone who spends hours in the direct sun without any water. The reality is that heat-related illness can develop faster and more subtly than that, even in people who feel fine one moment and don’t the next.
The Spectrum of Heat-Related Illness
Not all heat-related illness looks the same. It exists on a spectrum, from mild heat cramps to life-threatening heat stroke, and the difference between them can come down to how quickly symptoms are recognized and addressed.
Heat cramps are typically the first sign that the body is struggling. Painful muscle spasms, usually in the legs or abdomen, occur when physical activity causes excessive sweating and depletes the body of salt and fluids.
Heat exhaustion is more serious. It develops when the body can no longer regulate its temperature effectively and is often accompanied by heavy sweating, cold or clammy skin, nausea, dizziness and a rapid but weak pulse. People with heat exhaustion may feel faint or confused. Moving to a cool environment and rehydrating quickly can help, though medical attention is sometimes needed.
Heat stroke is a medical emergency. It occurs when the body’s core temperature rises to dangerous levels, typically above 104 degrees Fahrenheit, and the cooling system fails entirely. Symptoms include hot and dry skin, rapid heartbeat, loss of consciousness and severe confusion. Heat stroke can cause organ damage and death if not treated immediately. Call 9-1-1 without delay.
Who Is Most Vulnerable
Anyone can develop heat-related illness, though some people face a significantly higher risk. Older adults, young children and people with chronic conditions such as heart disease or diabetes are particularly susceptible. So are those taking certain medications, including diuretics and antihistamines, which can interfere with the body’s ability to regulate temperature. People who work or exercise outdoors and those without access to air conditioning are also at elevated risk.
How to Prevent It
Most heat-related illness is preventable with consistent, practical precautions:
- Drink water regularly throughout the day, not just when you feel thirsty
- Avoid outdoor activity during peak heat hours, generally between 10 a.m. and 4 p.m.
- Wear lightweight, light-colored, loose-fitting clothing
- Never leave children or pets in a parked vehicle, even briefly
- Check on elderly neighbors and family members during heat waves
- Take breaks in shaded or air-conditioned spaces if you’re working or exercising outside
When to Seek Care
Heat cramps and mild heat exhaustion can often be managed at home with rest, hydration and cooling measures. Seek medical attention if symptoms don’t improve within an hour, if the person is vomiting or if confusion develops. Heat stroke requires emergency care immediately.
When every minute counts, WMCHealth’s emergency team is equipped to treat heat-related illness at any level of severity. If you’re experiencing a medical emergency, call 9-1-1 or go to your nearest emergency room right away. For more information on emergency services at WMCHealth, visit wmchealth.org.