title: Thermoregulatory responses of children exercising in a hot environment.
abstract: OBJECTIVE
  To review possible peculiarities in biological mechanisms related to responses of thermoregulatory and specific sweat glands in exercise performed by children in hot environments.
  
  
  METHODS
  Review of 47 articles published between 1960 and 2011 in the electronic databases MedLine and SciELO Brazil using the following key-words: 'children', 'heat', 'sweating', 'thermoregulation', 'sweat gland', and 'exercise', alone or in combination, in addition to a doctoral thesis about the subject.
  
  
  RESULTS
  Pre-pubertal sweat rate during exercise is lower than among adults. Children have different thermoregulatory characteristics, with a small sweat output rate due to small sweat glands. High ratio between surface and body mass increases the absorption of heat during exercise under thermal stress in children, raising the risk of hyperthermia symptoms. However, great blood flow to skin contributes to the better control of thermal homeostasis in children. Small size of the gland, low cholinergic sensibility, low levels of circulating catecholamines during stress, and lack of androgenic hormone explain the occurrence of low elimination of sweat in exercises performed by children.
  
  
  CONCLUSIONS
  Children present immature sweat glands. Thus, physical activity combined with high temperatures is not well-tolerated by children and youngsters, with great vulnerability to thermal injury. In the heat, strict control of fluid intake and attentive monitoring of weather conditions should have especial attention for the safe practice of exercises.
authors.affiliation: Departamento de Educação Física, UFV, Viçosa, MG, Brasil.
authors.forename: Luis Henrique L S
authors.initials: LH
authors.lastname: Gomes
authors.forename: Miguel Araújo
authors.initials: MA
authors.lastname: Carneiro-Júnior
authors.forename: João Carlos B
authors.initials: JC
authors.lastname: Marins
mesh_terms: D001833:Body Temperature Regulation / Q000502:physiology*; D002648:Child; D015444:Exercise / Q000502:physiology*; D006706:Homeostasis; D006358:Hot Temperature; D006801:Humans; D013545:Sweat Glands / Q000502:physiology*