Heat Emergencies in Children: Recognizing Heat Exhaustion and Heat Stroke
Children overheat faster than adults. Knowing the difference between heat exhaustion and heat stroke — and acting within minutes — can save a life.
Children are significantly more vulnerable to heat-related illness than adults. Their bodies produce more heat relative to their size, they sweat less efficiently, and they are less likely to recognise or communicate early warning signs. On a hot summer day, a child playing outside can progress from overheated to dangerously ill in under 30 minutes.
Heat-related illness exists on a spectrum — from mild heat cramps to life-threatening heat stroke. Understanding this spectrum and knowing when to intervene is essential for every parent and caregiver.
The Heat Illness Spectrum
| Condition | Signs & Symptoms | Severity | Action |
|---|---|---|---|
| Heat cramps | Painful muscle cramps (usually legs or abdomen), heavy sweating during exercise | Mild | Move to shade, rest, sip cool water, gentle stretching |
| Heat exhaustion | Heavy sweating, cool/clammy/pale skin, nausea, headache, dizziness, weakness, fast weak pulse | Moderate — can progress to heat stroke | Move to cool area, remove excess clothing, cool wet cloths, sip water. Seek medical help if symptoms worsen or last over 1 hour |
| Heat stroke | High body temperature (above 40°C/104°F), hot/red/dry OR damp skin, rapid strong pulse, confusion, slurred speech, loss of consciousness, seizures | Life-threatening emergency | Call 911 immediately. Cool the child rapidly by any means available. Do NOT give fluids if unconscious |
Heat Exhaustion: First Aid Step by Step
Heat exhaustion is the body’s warning that its cooling system is being overwhelmed. Treated promptly, it resolves without lasting harm. Ignored, it can progress to heat stroke within minutes.
- Move to a cool environment — air-conditioned building, shade, or under a wet sheet with a fan
- Lay the child down and elevate their legs slightly to improve circulation
- Remove excess clothing — down to a single light layer
- Cool the skin actively — apply cool, wet cloths to the forehead, neck, armpits, and groin. Spray or sponge with cool water and fan the skin
- Offer small sips of cool water — not ice-cold, and only if the child is conscious and alert. Oral rehydration solution is ideal if available
- Monitor for 30-60 minutes — symptoms should begin improving within 15-30 minutes. If they worsen, or if the child’s temperature rises above 39°C, call 911
Heat Stroke: This Is a 911 Emergency
Heat stroke occurs when the body’s core temperature rises above 40°C (104°F) and the internal cooling system has failed. Without rapid treatment, heat stroke causes organ damage, brain injury, and death.
While Waiting for Paramedics
- Move the child to the coolest available environment
- Remove all clothing
- Cool the child aggressively: immerse in cool water if a tub or pool is available (this is the most effective method). If immersion is not possible, apply ice packs to the neck, armpits, and groin, and cover the body with wet sheets while fanning
- Do NOT give fluids if the child is unconscious or confused
- If the child is conscious and vomiting, place them on their side to protect the airway
- Monitor breathing — be prepared to begin CPR if the child becomes unresponsive and stops breathing normally
Babies and Heat: Special Considerations
Infants under one year are at the highest risk of heat-related illness because they cannot sweat effectively, cannot tell you they are too hot, and depend entirely on caregivers to regulate their environment.
Warning Signs in Babies
- Flushed, hot skin — check the chest and back, not just the forehead
- Unusual fussiness or lethargy
- Rapid breathing or panting
- Fewer wet nappies than usual (a sign of dehydration)
- Sunken soft spot (fontanelle) on the top of the head
- No tears when crying
Hot Car Danger: Never Leave a Child in a Parked Vehicle
On a 25°C (77°F) day, the inside of a parked car can reach 50°C (122°F) in under 30 minutes — even with windows cracked. A child’s body temperature rises three to five times faster than an adult’s. In Canada, leaving a child unattended in a vehicle is a criminal offence under the Criminal Code and provincial child welfare laws.
- Never leave a child in a parked car — not even for a minute
- Place your phone, bag, or a shoe in the back seat as a reminder to check before locking
- Teach older children how to honk the horn and unbuckle their seatbelt if they are ever trapped
- If you see a child alone in a hot car, call 911 immediately
Prevention: Keeping Kids Cool All Summer
- Hydrate proactively — offer water every 15-20 minutes during outdoor play, even if the child does not ask for it. Avoid sugary drinks and caffeine, which increase dehydration
- Schedule outdoor time wisely — avoid strenuous activity between 11 a.m. and 3 p.m. when UV and heat are highest
- Dress light — loose-fitting, light-coloured, breathable clothing. Wide-brimmed hats for sun protection
- Take shade breaks — 10-15 minutes in the shade for every 30-45 minutes of active play
- Cool down with water — sprinklers, spray bottles, and wet towels are effective cooling tools
- Acclimatise gradually — when a heat wave arrives, reduce activity intensity for the first few days to let bodies adjust
Frequently Asked Questions
What temperature is dangerous for children to play outside?
There is no single cutoff temperature, but Environment Canada issues heat warnings when temperatures reach 30°C or higher with a humidex of 40 or above. At these levels, children should limit outdoor activity, take frequent shade and water breaks, and avoid strenuous play between 11 a.m. and 3 p.m. Infants should be kept in cool, shaded environments whenever possible during heat warnings.
What is the difference between heat exhaustion and heat stroke?
Heat exhaustion is a warning stage where the body is struggling to cool itself — symptoms include heavy sweating, cool clammy skin, nausea, dizziness, and weakness. Heat stroke is a medical emergency where the body’s cooling system has failed entirely — the core temperature exceeds 40°C (104°F), the skin may be hot and dry, and the person may be confused, slurring speech, or unconscious. Heat exhaustion can progress to heat stroke if not treated promptly.
How quickly can heat stroke develop in a child?
Very quickly. A child playing in intense heat can progress from overheated to heat stroke in as little as 10 to 15 minutes. In a parked car, a child’s body temperature can reach dangerous levels in under 15 minutes. Children’s bodies heat up three to five times faster than adults, which is why prevention and early recognition are so critical.
Can babies get heat stroke?
Yes, and they are at higher risk than older children. Infants under one year cannot sweat effectively, cannot communicate that they are overheated, and depend entirely on caregivers to regulate their environment. Watch for flushed hot skin, unusual fussiness or lethargy, rapid breathing, fewer wet nappies, and a sunken soft spot on the head. These are signs that the baby needs to be cooled immediately.
Should I give ice water to a child with heat exhaustion?
No. Offer cool water in small sips, not ice-cold water. Ice-cold drinks can cause stomach cramps and vomiting, which worsens dehydration. Oral rehydration solutions are ideal if available. If the child is confused, vomiting, or unconscious, do not give any fluids by mouth — call 911 immediately and focus on external cooling.