By Brandon Pollock, PhD, ACSM-EP-C
When planning picnics, sporting events, or other outside activities this summer, set aside some extra time to ensure proper preparations are being made for children (< 13 years) that may be attending. There are several physiological differences between children and adults which suggest that children thermoregulate inferiorly to adults.
Children have undeveloped sweat glands, so they sweat at a slower rate than adults. They produce more heat per unit body mass than adults. A child performing physical activity in the heat requires a greater amount of blood to maintain appropriate body temperature, leaving less for their working muscles.
Despite these limitations, according to the American Academy of Pediatrics (AAP), when exercising in an ambient temperature (68.0 – 74.3 °F) children that stay hydrated still experience thermoregulatory ability compared to adults. This is because children have a higher body surface to mass ratio than adults, which they rely on greater in order to evaporate sweat equally and as efficiently as adults with an added bonus of retaining more water. However, in the heat this thermoregulatory strategy is outweighed by their physiological limitations. During exercise under heat stress, children have a greater risk of experiencing heat related illness compared to adults.
It is very important that children/ young adults use extra precaution when choosing to exercise or perform any physical activity in the heat.
Check the weather. On hot summer days, the time of day you decide to workout can be very important. Working out early in the morning or later in the day should be a good habit to get into if you are struggling to bear the heat.
Choose the right clothing. Children have an enhanced ability to lose heat through sweat evaporation. Choosing the wrong exercise attire could reduce or potentially even eliminate this ability. Loose, light-colored cotton or any sweat promoting material will work fine for shirt and shorts.
Stay hydrated. The AAP has stated children pose no added risk of developing heat illness during exercise in an ambient temperature if they remain hydrated. Children should drink 4 – 8 ounces of water 1 to 2 hours and 10 – 15 minutes before exercise.
Get enough sleep. Sleep deprivation disrupts thermoregulation of skin temperature. Begin with 10 – 12 hours per night and reduce as needed.
Keep a close eye out for signs and symptoms of dehydration or heat illness. Dry mouth, thirst, headache, dizziness, cramps, extreme fatigue can all be signs of dehydration or heat cramps. This can progress to heat exhaustion and eventually lead to heat stroke.
Sunscreen. Protecting your skin is just as important as everything else. SPF 45 is a good place to start.
Listen to your body. If you experience symptoms of heat illness stop exercising immediately; seek, share and rehydrate. If symptoms get worse seek further help or call your doctor.
Article’s Resources
1) American College of Sports M, Armstrong LE, Casa DJ, et al. American College of Sports Medicine position stand. Exertional heat illness during training and competition. Medicine and science in sports and exercise. Mar 2007;39(3):556-572.
2) Falk B, Dotan R. Children's thermoregulation during exercise in the heat: a revisit. Applied physiology, nutrition, and metabolism = Physiologie appliquee, nutrition et metabolisme. Apr 2008;33(2):420-427.
3) Gomes LH, Carneiro-Junior MA, Marins JC. Thermoregulatory responses of children exercising in a hot environment. Revista paulista de pediatria : orgao oficial da Sociedade de Pediatria de Sao Paulo. Jan-Mar 2013;31(1):104-110.
4) http://www.nata.org/
5) Rowland T. Thermoregulation during exercise in the heat in children: old concepts revisited. Journal of applied physiology. Aug 2008;105(2):718-724.
6) Romeijn N, Verweij IM, Koeleman A, et al. Cold hands, warm feet: sleep deprivation disrupts thermoregulation and its association with vigilance. Sleep. Dec 2012;35(12):1673-1683.