Supporting Your Child’s Hydration This Summer
- Alto
- 2 days ago
- 7 min read
As the warmer months settle in and children spend more time playing outdoors, attending childcare, or simply enjoying the brighter longer days, the risk of fluid loss and dehydration increases. It’s important for parents and childcare‑centre staff to understand the signs, risks and prevention strategies of dehydration in children. This article explores why children are especially vulnerable to dehydration, how dehydration affects their body and brain, and practical steps parents can take to safeguard their child’s hydration through summer.
What is dehydration in children?
Dehydration occurs when a child loses more body water (and often salts/electrolytes) than they take in. In children, causes include not drinking enough, high heat, vigorous activity, fever, diarrhoea or vomiting. According to the clinical guidelines of The Royal Children’s Hospital (RCH) (Melbourne), the best measure of dehydration is weight loss from “pre‑morbid” (normal) weight – for example, a 10 kg child who now weighs 9.5 kg has a 5 % fluid deficit. Children have physiologically greater vulnerability: higher body‑surface‑area to mass ratio (so more heat loss and fluid loss) and less developed regulation of fluid intake.
Why children are at higher risk
Young children may not recognise or act on thirst, or may be so engrossed in play that they forget to drink. According to recent review research, “the thirst mechanism in youth is not fully efficient. They often do not feel the need to drink, even when their bodies require fluids.”
In hot weather or during vigorous outdoor play (or when ill with fever, vomiting or diarrhoea) fluid losses can be rapid and significant.
Many symptoms of mild dehydration are subtle (e.g., reduced urine output, slightly darker urine, mild thirst) and can be overlooked until more serious signs develop. For example, the RCH “Kids Info” fact sheet states that a child with mild dehydration may simply "feel thirsty" or “urinate less than usual”.
Importance & Benefits of hydration
Hydration is essential for maintaining bodily functions including circulation, temperature regulation, digestion, waste removal, and critically – brain function. Emerging evidence indicates that even mild dehydration (fluid losses of ~1–2 % of body weight) can impair cognitive performance, attention, memory and mood.
For example:
The review “Effects of hydration status on cognitive performance and mood” found that children and other vulnerable groups showed impaired attention and memory with dehydration, and that water consumption improved mood and some cognitive tasks.
A study in school‑aged children observed that providing water reduced dehydration during the day, although the cognitive test results were mixed (but there were suggestive improvements in visual attention). Thus, preventing dehydration isn’t just about avoiding heat exhaustion — it supports children’s learning, mood, concentration and wellbeing.
Thirst as a latent (late) indicator of dehydration
A key concept: thirst is a signal, but by the time a child feels thirsty, some fluid deficit has often already occurred. In physiological terms, thirst is a later compensatory signal once the body senses increased osmolality (concentration of body fluids) or reduced volume. In children whose thirst mechanism may be under‑developed, relying solely on “tell your child to drink when they feel thirsty” may miss early dehydration. This is supported by research noting children's thirst response is not fully reliable. In practical terms: a child may already have a 1–2 % water loss before significant thirst is felt, and at this stage cognitive/attention effects may already be present. So proactive hydration is far better than reactive.
The negative loop: reduced cognition, lack of planning, dehydration
Children’s developing executive functions (planning ahead, monitoring their own body needs, remembering to drink) are less mature than adults’. Combine this with potential dehydration’s effect on cognition and mood, and a “negative loop” can occur:
1) The child doesn’t recognise thirst (or ignores it) → 2) They delay drinking fluids → 3) Mild dehydration develops → 4) Cognitive performance (attention, memory, planning) drops (e.g., less able to recall to drink, less able to adjust behaviour) → 5) As cognitive load increases (e.g., in a busy childcare or play setting), they may further neglect hydration → 6) Dehydration deepens, mood or energy drops, reducing fluid intake further.
Research shows that mild dehydration impairs attention, short‑term memory, and mood states like alertness and confusion. A recent study found that even when children’s motor skills—such as coordination and strength—remained unaffected, their cognitive functions, including focus, processing speed, and attention span, significantly declined during mild dehydration. This means that children may appear fine physically, continuing to move and play as usual, while already experiencing reduced cognitive performance. This interplay is particularly relevant during hot summer days or extended activity periods when children may not spontaneously stop to drink. Recognising that thirst alone is insufficient and supporting proactive hydration and cues is therefore crucial.
Case example
Imagine a 5‑year‑old in a playground playing enthusiastic basketball during a hot afternoon. They don’t feel thirsty until later, and because they are so engaged they skip drinking for an hour. By then they may already be mildly dehydrated. Their attention to game rules, ability to self‑regulate (rotate out vs keep playing) may reduce, they might get irritable or fatigued, and forget to drink even further. Without adult prompts they may spiral into reduced intake and worsening hydration status. This scenario illustrates how the planning/attention loop + thirst delay + hot weather can amplify risk.
Practical Application
Tips & strategies for parents
Here are evidence‑based and practical ways to support children’s hydration this summer:
Make water readily available
Encourage children to carry a labelled water bottle when at home, childcare or on outings.
Schedule regular drink breaks (e.g., every 20‑30 minutes if active outdoors). Don’t rely solely on “when the child says they are thirsty”.
For younger children: encourage sipping rather than large gulping, use fun cups or straws to make drinking appealing.
Choose the right fluids
For most healthy children, plain water is excellent.
If a child is ill (vomiting/diarrhoea) or already showing dehydration signs, use an oral rehydration solution (ORS) or follow guidelines for fluid replacement.
Avoid relying on sugary soft‑drinks or “sports drinks” for hydration in regular play; they can be counter‑productive (high sugar may worsen diarrhoea or delay rehydration) according to Australian guidance.
Encourage fluids before outdoor activity and after, not just during illness.
Use cues and routines
At childcare or home, establish “water rituals”: e.g., on arrival, after every 20 minutes of play, after snack, before leaving the playground.
For younger children who may lack internal cues, adult reminders are key.
Teach children simple self‑regulation: “When you finish your snack, take a drink”, “After every game round, we refill bottles”.
Monitor for signs of dehydration earlyAccording to RCH Kids Info: signs of mild dehydration include increased thirst or urinating less than usual. Signs of moderate dehydration: less active, cooler hands/feet, dry mouth/lips/tongue, darker urine. Serious dehydration (seek medical care) includes: cold or mottled skin, sunken eyes, very reduced urine, lethargy. Monitor fluid intake during hot days, especially if the child is playing vigorously, has fever, diarrhoea or vomiting.
Encourage hydration during illness or heat stress
If the child has fever, vomiting, diarrhoea, increase fluids.
Follow the guideline advice: e.g., for children >10 kg, “small sips of clear fluids often; aim up to 100 mL per hour for four hours” in mild/moderate cases.
If they refuse fluids or the signs worsen, seek health advice.
Link hydration to learning and attention
Remind older children that drinking water helps their brain — better attention, memory and mood. Research shows even mild dehydration impairs cognitive performance.
At childcare or school settings, integrate short “water breaks” before transitions or high‑focus tasks (e.g., after playground, before craft or group time).
Troubleshooting options
If child refuses to drink: Make it fun — infused water (e.g., a slice of cucumber or strawberry), use a favourite cup/straw, set little drinking challenges (e.g., refill bottle before next game).
If child plays for extended periods outdoors: Ensure shade and regular drink breaks, avoid very intense play during hottest parts of the day (midday‑afternoon), bring portable cool water.
If you notice attention or behaviour changes: Consider whether dehydration may be contributing (inattention, irritability, fatigue). Offer a drink and observe whether symptoms improve.
If child is ill with vomiting/diarrhoea: Use ORS if advised, monitor for signs of dehydration (reduced urine, dark urine, sunken eyes) and seek medical advice if fluid intake becomes poor. The RCH guidelines emphasise weight loss, urine output and clinical signs to assess dehydration severity.
If child seems to “forget” to drink: Set timers, use alarms in childcare or at home, include hydration check as part of daily routine (e.g., after arrival, snack time, before outdoor play).
As summer approaches, proactive attention to children’s hydration is essential. Because thirst can lag behind fluid loss, and because children may not plan ahead or stop to drink when needed, the responsibility lies with parents and childcare staff to provide, model and support good fluid habits. Adequate hydration not only protects physical health, but supports attention, mood and learning. By making water easy to access, establishing consistent routines, monitoring for early signs of dehydration, and linking drinking water to daily activities, we can help children enjoy summer safely and stay at their best—physically, mentally and developmentally.
References:
The Royal Children’s Hospital (RCH). Clinical Practice Guidelines: Dehydration. Accessed via https://www.rch.org.au/clinicalguide/guideline_index/dehydration/ Royal Children's Hospital
RCH Kids Info: Dehydration in babies and children. https://www.rch.org.au/kidsinfo/fact_sheets/Dehydration/ Royal Children's Hospital
Zborowski M et al. The Role of Hydration in Children and Adolescents — A Narrative Review. Nutrients. 2025;17(17):2841. MDPI
Masento NA et al. Effects of hydration status on cognitive performance and mood. British Journal of Nutrition. 2014;111(10):1841‑1852. Cambridge University Press & Assessment
Yüksel, S., & Akıl, M. (2024). Mild Dehydration Triggered by Exercise Reduces Cognitive Performance in Children, But Does Not Affect Their Motor Skills. Journal of the Academy of Child and Adolescent Neuropsychology, 4(3), 627–635. https://www.tandfonline.com/doi/10.1080/27697061.2024.2362709