Heat exhaustion (when the body overheats) - Infants
What it is
During extreme temperatures or intense physical activity in a hot environment, the body may have trouble cooling itself. When the body overheats, your child may have a headache, diarrhea, vomiting, or cramps in their arms, legs or stomach.
What you can do at home
What to do
- Take your child to a cool place as quickly as possible. For example, take them to an air-conditioned or well-ventilated room or a shady spot.
- Ask your child to rest or lie down.
- If your child says they are dizzy, lie them down and raise their legs above their heart (for example, by putting a pillow under their legs).
- If your child has cramps, loosen their clothing and gently massage the sore area.
- Frequently offer your child something to drink:
- For children under six months old: Breastfeed them or give them commercial infant formula more often.
- For children 6 to 12 months old: Give them water, breast milk, or commercial infant formula more often.
- For children more than 12 months old: Give them water, milk (breast milk, commercial infant formula, or dairy milk) or oral rehydration drinks from the pharmacy (Pedialyte, Gastrolyte). Follow the advice of your pharmacist.
- If your child is more than 12 months old and your pharmacy has no oral rehydration drinks, you can prepare the following at home:
- 360 ml unsweetened orange juice
- 600 ml boiled water, cooled
- 2.5 ml (½ tsp) salt
Avoid
- Avoid intense physical activities for at least 12 hours.
When to seek medical attention
If your child have any of these signs:
- your child has not drunk anything in over 4 hours;
- Your child has diarrhea or is vomiting;
- Your child is more than 3 months old and has a fever, or their underarm temperature is less than 39 °C (102.2 °F), or their rectal temperature is less than 40 °C (104 °F).
Call 811, Option 1, to speak with a nurse, or contact a healthcare professional (pharmacist, doctor, or nurse practitioner), if any of the signs listed above apply.
When to go to the hospital right away
If your child is less than 3 months old and has a fever.
Your child is more than 3 months old and has a fever, or their underarm temperature is higher than 39 °C (102.2 °F), or their rectal temperature is higher than 40 °C (104 °F).
Your child:
- Is floppy when awake;
- is difficult to wake or is unusually sleepy;
- is slow to react;
- is behaving unusually.
Your child is having convulsions (body shaking uncontrollably).
They are not improving despite the advice above.
Your child is very thirsty and has no tears when crying.
Your child pees fewer than 4 times in 24 hours, or has not peed at all for more than 8 hours.
Need help?
Call Info-Santé at 811, Option 1, to speak with a nurse at any time.
Go to the pharmacy for advice on medications or treatment.
Make an appointment at your medical clinic or CLSC.
If you do not have a family doctor, go to https://gap.soinsvirtuels.gouv.qc.ca/en or call 811, Option 3.
Last update: January 1, 2026
The information sheet does not replace medical advice. If you have any doubts, contact a healthcare professional.
References:
- Guides infirmiers d’éducation aux autosoins, CIUSSS de la Capitale-Nationale
See also
See the details of Gastroenteritis
Gastroenteritis
- Infants
- Children
- Adults
- Seniors
See the details of Superficial Wound
Superficial Wound
- Infants
- Children
- Adults
- Seniors