title: Sunscreen Use and Sweat Production in Men and Women.
abstract: BACKGROUND
  Sunscreen lotions are important to protect the skin during outdoor exercise, but they may interfere with sweating.
  
  
  OBJECTIVE
  To measure the effect of 2 water-resistant sunscreens on local sweat production in men and women exercising in the heat and to compare those effects with the expected inhibition resulting from the use of an antiperspirant.
  
  
  METHODS
  Randomized crossover study.
  
  
  METHODS
  Exercise in the heat (ambient temperature = 30.2°C ± 0.4°C dry bulb and 58% ± 4.3% relative humidity) in a controlled-environment laboratory.
  
  
  METHODS
  Twenty physically active, apparently healthy college students, 10 men (age = 22.5 ± 2.8 years, height = 1.771 ± 0.069 m, mass = 70.2 ± 11.0 kg) and 10 women (age = 22.2 ± 3.2 years, height = 1.625 ± 0.075 m, mass = 57.7 ± 7.9 kg).
  
  
  METHODS
  With sweat-collection patches applied to their right and left scapular regions, the participants performed 2 exercise sessions on consecutive days. We assigned skin treatments (antiperspirant; organic chemical sun filter, sunscreen A; inorganic physical sun block, sunscreen B; no lotion) randomly to side and session. Participants pedaled at 79% ± 1% of maximum heart rate for 20 minutes in the heat.
  
  
  METHODS
  Scapular localized sweat rate.
  
  
  RESULTS
  No baseline, environmental, or exercise condition was different among skin treatments. Scapular localized sweat rate was lower for the antiperspirant treatment (88.3 μL/min·dm2; 95% confidence interval [CI] = 82.0, 94.7 μL/min·dm2) and the inorganic physical sun block (sunscreen B) treatment (99.3 μL/min·dm2; 95% CI = 93.1, 105.5 μL/min·dm2) than for the organic chemical sun filter (sunscreen A) treatment (114.8 μL/min·dm2; 95% CI = 108.8, 120.6 μL/min·dm2) or the no-lotion treatment (122.6 μL/min·dm2; 95% CI = 116.2, 129.0 μL/min·dm2; P < .01).
  
  
  CONCLUSIONS
  The inorganic physical sun block, sunscreen B, hindered effective sweating to the same extent as the antiperspirant, whereas the treatment with the organic chemical sun filter, sunscreen A, was not different from the control treatment. At this stage, it is not possible to identify the specific ingredient responsible for the effect.
authors.affiliation: Human Movement Science Research Center, University of Costa Rica, San Jose.
authors.forename: Jorge
authors.initials: J
authors.lastname: Aburto-Corona
authors.affiliation: Human Movement Science Research Center, University of Costa Rica, San Jose.
authors.forename: Luis
authors.initials: L
authors.lastname: Aragón-Vargas
mesh_terms: D000328:Adult; D001831:Body Temperature / Q000502:physiology*; D001833:Body Temperature Regulation / Q000187:drug effects / Q000502:physiology; D018592:Cross-Over Studies; D015444:Exercise / Q000502:physiology; D005260:Female; D006358:Hot Temperature; D006801:Humans; D008297:Male; D013473:Sunscreening Agents / Q000009:adverse effects*; D013546:Sweating / Q000187:drug effects / Q000502:physiology*; D060726:Torso; D055815:Young Adult
chemical_list: D013473:Sunscreening Agents
keywords: exercise; hyperthermia; skin care; sweat rate; thermoregulation