Hydration in infants and children

The need to maintain an adequate hydration status is the same for infants and children as for adults. The amounts of water needed to achieve this will be different though, and there are some key differences across the lifespan. This guide highlights special considerations that will help make sure our children stay properly hydrated.

blueThe total body water content in infants is much higher than in adults.

The total body water content in infants is much higher than in adults

greenAs infants and children get older, recommended levels of water intake increase.1 Bigger bodies need a higher intake to replace water lost via breathing, sweating and urine. There is also some evidence suggesting that children may do better on some measures of learning, memory and cognition when well hydrated.2-4

Daily adequate water intake in infants and children

Daily adequate water intake in infants and children

Infants and children are particularly vulnerable to the effects of dehydration. However, it is not easy to tell when infants need water. Children involved in activities may forget to drink, so those caring for them need to ensure hydration is adequate. This is particularly important in hot weather or when a child is ill.

Tips for keeping infants and children hydrated, especially in hot environments

  • Breastfed infants stay well hydrated but formula-fed infants may need additional water intake
  • Offer children drinks before and during play times, and encourage them to take breaks in the shade
  • Offer drinks that your child enjoys. All drinks (e.g. water, milk and soft drinks) help with hydration, but remember that some drinks will add unwanted calories to your child’s diet
  • Cool drinks may be preferred in warm weather, but hot drinks may be best when it is cold
  • Many foods, such as fruit and vegetables, have a high water content and can contribute to water intake

orangeDiarrhoea and vomiting are common in infants and children, with causes including viral or bacterial infection, intolerance or allergy, chronic conditions (e.g. Crohn’s disease, ulcerative colitis, irritable bowel syndrome) and medications or treatments.5 Diarrhoea and vomiting can lead to dehydration if fluid intake is not increased sufficiently.6

Key signs of mild to moderate dehydration


  • Fewer wet nappies
  • Sunken fontanelle


  • Fast or deep breathing
  • Cool extremities
  • Increased or decreased heart rate
  • Sunken eyes, dry mouth/tongue
  • Decreased tears and urine
  • Tired or restless

It is essential to ensure a child with diarrhoea and/or vomiting is properly hydrated, as well as treating them with any necessary medication or dietary changes.7,8

How to treat dehydration in children

If you would like more information about the themes discussed in this article, the ICASH website contains a range of materials which explore hydration-related subjects in more detail.

1. EFSA Panel on Dietetic Products, Nutrition, and Allergies (NDA); Scientific Opinion on Dietary Reference Values for Water. EFSA Journal 2010; 8(3):1459. Available at: http://www.efsa.europa.eu/en/efsajournal/ pub/1459.htm.
2. Edmonds CJ, Jeffes B. Does having a drink help you think? 6-7-year-old children show improvements in cognitive performance from baseline to test after having a drink of water. Appetite 2009;53(3):469-72.
3. Edmonds CJ, Burford D. Should children drink more water?: the effects of drinking water on cognition in children. Appetite 2009;52(3):776-9.
4. Benton D, Burgess N. The effect of the consumption of water on the memory and attention of children. Appetite 2009;53(1):143-6.
5. WebMD (2014) The basics of diarrhoea. Available at: www.webmd.com/digestive-disorders/digestive-diseases-diarrhea.
6. Churgay CA & Aftab Z (2012) Gastroenteritis in children: Part I. Diagnosis. Am Fam Physician 85(11):1059-1062.
7. Churgay CA & Aftab Z (2012) Gastroenteritis in children: Part II. Prevention and management. Am Fam Physician 85(11):1066-1070.
8. NHS Choices (2013) Treating dehydration. Available at: www.nhs.uk/Conditions/Dehydration/Pages/ Treatment.aspx.