Heat Illness in Children: Prevention and When to Seek Care

An independent educational resource prepared by Mark M. Simonian, MD, FAAP

Sources checked: August 5, 2026     |     Medical review completed: August 5, 2026

This page is for general education only and does not replace individualized medical advice. This resource does not establish a doctor-patient relationship. For questions about your own child, contact your child's current healthcare professional.

Magnolia Pediatrics, Valley Children's Healthcare

2497 E. Herndon Avenue, Suite 101, Clovis, CA 93611     |     559-538-3070

Children can become ill from heat during outdoor play, sports, hot weather, high humidity, or time in a hot car or building. The heat index, which combines temperature and humidity, can matter more than the thermometer alone. Babies, young children, children with chronic health conditions, and active athletes need extra protection.

Urgent Warning Signs - Check This First

Heatstroke is a medical emergency. Begin cooling while emergency help is on the way. Do not give anything by mouth to a child who is confused, vomiting repeatedly, unable to swallow safely, or unconscious.

CALL 911 NOW

  • Confusion, unusual behavior, slurred speech, seizure, fainting, loss of consciousness, inability to wake normally, or signs of shock after heat exposure

  • A very high body temperature with hot skin, whether dry or sweaty, especially with headache, rapid pulse, vomiting, or altered behavior

  • A child found alone in a hot car, a closed vehicle, or another dangerously hot setting. Remove the child if it is safe to do so, call 911, and begin cooling

  • Trouble breathing, blue or gray lips or face, or you believe your child is in immediate danger

GET EMERGENCY MEDICAL CARE NOW

  • Fainting, too weak or unsteady to stand or walk, severe dizziness, severe headache, persistent vomiting, or worsening symptoms after leaving the heat

  • A temperature of 104 F (40 C) or higher after heat exposure, or any heat-related illness with a child who looks seriously ill

  • Severe muscle pain, cramps that do not improve with rest and fluids, dark brown or tea-colored urine, or severe weakness after strenuous activity in heat

  • Signs of significant dehydration: no urine for about 8 hours, very dark urine, dry mouth, no tears when crying, sunken eyes, marked sleepiness, or inability to keep fluids down

CONTACT YOUR CHILD'S HEALTHCARE PROFESSIONAL TODAY

  • Heat-exhaustion symptoms such as heavy sweating, pale or clammy skin, weakness, headache, nausea, muscle cramps, dizziness, or a rapid pulse do not clearly improve within an hour of rest and cooling

  • Fever, dizziness, weakness, vomiting, or dehydration continues after moving to a cool place and offering fluids to a fully alert child

  • A baby younger than 12 weeks has fever or is not acting normally after heat exposure

  • Your child has heart, kidney, lung, neurologic, or other chronic health conditions; takes medicines that may affect hydration or heat tolerance; or has repeated heat symptoms

  • You are unsure whether symptoms are due to heat, infection, medicine effects, or another illness

What to Do for Mild Heat Exhaustion

Use these steps only for a child who is awake, alert, able to swallow safely, and has no emergency warning sign.

  • Stop activity and move the child to air conditioning, shade, or another cool place. Remove extra clothing and equipment

  • Use cool water on the skin, a cool shower or bath, wet cloths, and a fan if available. Do not use ice-cold water that causes shivering

  • Offer frequent small sips of water. For prolonged sports activity, follow the child's usual sports-hydration plan; avoid forcing large amounts at once

  • Do not return to sports, play, or heat exposure until symptoms have fully resolved and the child feels back to normal. Seek medical advice for significant or recurrent episodes

How to Prevent Heat Illness

  • Check the heat index and plan outdoor activity for cooler parts of the day. Build in frequent shade and water breaks, especially during a heat wave or when a child is not acclimated to the heat

  • Encourage water regularly before, during, and after activity. Do not wait for thirst alone, especially in young children who may not recognize or describe thirst

  • Use light, loose clothing and broad-brimmed hats when practical. Take breaks from helmets, pads, or heavy equipment only when it is safe to do so

  • Never leave a child alone in a parked car - not even for a short time and not even with a window cracked. Make a routine of checking the back seat every time you leave the vehicle

  • Watch children closely around hot tubs, very hot baths, saunas, poorly ventilated rooms, and outdoor play areas with little shade

Heat Cramps, Heat Exhaustion, and Heatstroke

  • Heat cramps are painful muscle spasms, usually during or after exertion in heat. Rest, cooling, and fluids can help, but ongoing cramps or other symptoms need medical advice

  • Heat exhaustion usually involves heavy sweating, pale or clammy skin, thirst, weakness, headache, nausea, dizziness, cramps, or fainting. It can progress to heatstroke

  • Heatstroke can include very high temperature, confusion, collapse, seizure, hot skin that may be dry or sweaty, rapid pulse, and loss of consciousness. Call 911 and cool rapidly

  • A temperature number alone does not determine severity. Changes in alertness, breathing, ability to walk, vomiting, hydration, and how quickly symptoms are changing are equally important

Call Preparation

  • Child's age, health conditions, medicines, activity level, time in the heat, heat index if known, and whether the child was in a car or enclosed space

  • Symptoms, timing, temperature and how it was measured, fluid intake, urine output, vomiting, fainting, behavior changes, and ability to stand or walk

  • Cooling steps already used and whether symptoms improved, stayed the same, or worsened

  • Any sports team, camp, or school heat plan and whether the child has had previous heat illness

Related Guides

  • Fever and Illness: When to Seek Care

  • Vomiting, Diarrhea and Dehydration: When to Seek Care

  • Dizziness and Fainting in Children: When to Seek Care

  • Child Safety Checklist: Infants and Young Children

Sources and Medical Review

  • HealthyChildren.org (American Academy of Pediatrics), Extreme Heat: Tips to Keep Kids Safe When Temperatures Soar: Read source

  • HealthyChildren.org (American Academy of Pediatrics), How to Keep Young Athletes & Active Kids Safe in Hot Weather: Read source

  • HealthyChildren.org (American Academy of Pediatrics), Heat Related Illnesses: Read source

  • Centers for Disease Control and Prevention, Infants and Children and Heat: Read source

  • Centers for Disease Control and Prevention, Heat-Related Illnesses: Read source