A recently published study from Australia sought to determine whether children (aged 10–16) are at greater risk of hyperthermia and dehydration than adults (aged 18–40) during exercise in hot conditions and to assess how well an adult sweat-rate calculator estimates children’s sweat rates.
They had 68 active children and 24 adults perform 3 separate 45-minute treadmill sessions under 2 environmental conditions while core temperature was continuously monitored and dehydration was assessed by changes in body mass.
Key takeaways included: 1) children and adults respond similarly in terms of core temperature increases and dehydration when exercising in hot conditions (up to 104 degrees F); 2) an adult-derived sweat-rate calculator estimates children’s sweat lossess quite accurately; 3) to promote safety, hydration behavior remains critical—even if physiological risk levels are similar between kids and adults.
The authors concluded that practitioners can potentially reduce behavioral dehydration risks from inadequate fluid consumption using an existing adult sweat rate calculator for children.
Source: Smallcombe JW, Topham TH, Brown HA, et al. Thermoregulation and dehydration in children and youth exercising in extreme heat compared with adults. Br J Sports Med. 2025 Jul 31;59(16):1151-1159. doi: 10.1136/bjsports-2025-109832.
