Kids, heat and play: what new Australian research says

For years, parents and coaches were told that children are more vulnerable to heat than adults. Smaller bodies, less sweating, a higher surface-area-to-mass ratio: the logic seemed sound. But a major Australian study published in 2025 has added important nuance.

What the study found

Researchers at the University of Sydney's Heat and Health Research Centre studied 68 fit, active children aged 10 to 16 and 24 adults. Each person walked or ran on a treadmill for 45 minutes in warm (30°C) and hot (40°C) conditions, while the team tracked core temperature and sweating.

The headline finding: children aged 10 to 16 heated up and sweated much like adults. Their risk of overheating and dehydration during exercise up to 40°C was similar to adults', contradicting older advice that children are physiologically more vulnerable.

A 2026 systematic review from Brock University reached a similar conclusion. Children tend to sweat less than adults, but they send more blood to the skin to shed heat, so overall their temperature regulation works about as well.

So where does the risk come from?

The researchers were clear that children can still be at higher risk in practice, but for behavioural reasons rather than physiological ones:

• Kids are often more active than adults, and for longer
• They're less likely to notice they're thirsty, or to stop and drink
• They're less likely to rest, seek shade or take off a layer without being told
• They don't always say when they feel unwell

Those are exactly the patterns we see at school. A child absorbed in a game of handball at lunch isn't thinking about hydration or whether their jumper is still on.

Where clothing fits in

This research is a useful reminder not to overstate the case. Children's bodies are not fragile in the heat. But clothing still shapes how comfortable they feel and how effectively their bodies can do their cooling work.

Because children rely heavily on shedding heat through their skin, fabrics that let heat and moisture escape support that process. Clothing that traps heat, or stays damp against skin, works against it. And comfort itself matters: a hot, sticky, itchy child is less focused in class and less keen to be active.

Practical tips for hot school days

• Pack a large water bottle and encourage kids to drink at every break, not just when thirsty
• Choose breathable summer uniforms in lightweight natural fabrics
• Make layers easy to remove. A cotton cardigan or zip jumper is easier to take off than a heavy pullover
• Hats and shade remain essential under Australia's UV
• Know the signs of heat illness: headache, dizziness, nausea, unusual tiredness or irritability
• Check your school's heat policy. Many schools adjust activity and uniform rules on very hot days

Our take

We love that this research gives parents better, more accurate information. It doesn't mean heat doesn't matter. It means the biggest wins come from habits and choices: drinking water, finding shade, and wearing clothes that let a child's body do what it already does well.

We're designing Natural Schoolwear to stay out of the way: light, breathable natural fibres that let kids run hard at lunch and still feel comfortable in maths after.

Sources: Smallcombe et al., British Journal of Sports Medicine, 2025; Falk et al., Temperature, 2026.