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Heat-related Illness in Infants and Young Children

Last Updated: July 27, 2022
HealthLinkBC File Number: 35c
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Heat and humidity can go up in the summer months, making it feel hotter outside than normal. Extreme heat happens when the heat and humidity are much higher than we would expect during a normal summer day.

Extreme heat can be harmful to anyone's health, but infants (0-1 year) and young children (1-5 years) may be at a higher risk of heat-related illness.

Why are infants and children at greater risk?

Infants and children can become dehydrated quickly due to a high metabolism and less effective kidneys, putting them at a higher risk of heat-related illness.

Infants and children also have more sensitive skin, making them more likely to get a sunburn. Sunburns can make heat-related illnesses more likely and more severe.

Sweat is the body’s way of cooling down. Infants can’t sweat, which means that they can develop a heat-related illness much faster than an older child or adult.

What signs should I look for?

Your infant or young child may not be able to tell you what they are feeling or what they need. This makes it especially important to monitor them during extreme heat events. If your infant or child is sick, watch them closely, as heat can make the symptoms of their illnesses worse (e.g., dehydration due to nausea and vomiting).

Symptoms of heat-related illness (like heat stroke) include:

  • Feeling very tired or weak
  • Leg or stomach cramps
  • Vomiting and diarrhea
  • Dizziness, confusion, or difficulty speaking
  • Seizures or passing out

Signs of dehydration in infants and young children include:

  • Peeing less
    • Fewer than 4 wet diapers in 24 hours in infants (0-1 year)
    • Fewer than 3 wet diapers in 24 hours in children (1-5 years)
    • Peeing little, and fewer than 4 times a day for children not in diapers
  • Being extra thirsty
  • Seeming more tired or fussy than normal
  • No tears when crying
  • Dry skin, mouth, and tongue
  • Faster heartbeat
  • Shallow breathing (especially with infants)
  • Sunken eyes
  • Sunken soft spot on the head (if 18 months or younger)

Keep in mind that infants and young children may not show the early signs and symptoms of heat-related illness. They may just look unwell or be more fussy than usual.

What should I do if my child is showing signs of heat-related illness?

Contact a health care provider if your infant or young child shows signs of a heat-related illness. You can also call HealthLink BC at 8-1-1 anytime to speak to a registered nurse. It's important that you begin cooling down your child right away. Get them out of the heat and remove their clothes. Use a fan or spritz them with cool water. Offer them frequent sips of water.

If your child is showing serious signs of a heat-related illness, like passing out or having a seizure, call 9-1-1

What should I do if my child is dehydrated?

Contact a health care provider right away if your infant or young child shows signs of being dehydrated. You can also call HealthLink BC at 8-1-1 anytime to talk with a registered nurse.

Here are some steps you can take if your child is showing signs of dehydration:

Under 1 Year

  • Give your child lots of breastmilk or formula if they are under 1-year-old
  • Speak to a health care provider before offering your child fluid replacement products like Pedialyte

1 Year and Older

  • Give your child fluid replacement products, such as Gastrolyte or Pedialyte if they show signs of dehydration
  • Use diluted apple juice (½ water, ½ apple juice) as an alternative fluid replacement drink if your child is 2 years and older. These drinks are better than water for rehydration because they combine fluid, sugar, and electrolytes

See your health care provider immediately if symptoms do not improve or worsen. Get emergency medical care if your infant or child is very sleepy or isn’t responding to you.

For More Information

For more information on heat-related illness, see the following HealthLink BC Files:

For more information on keeping children cool see: https://www.canada.ca/content/dam/hc-sc/documents/services/publications/healthy-living/keep-children-cool-extreme-heat/extreme-heat-brochure-keep-children-cool-en.pdf.