title: The effect of prolonged light intensity exercise in the heat on executive function.
abstract: OBJECTIVE
  When people are involved in outdoor activities, it is important to be able to assess a situation and make rational decisions. The goal of this study is to determine the effects of 90 minutes of light-intensity exercise in a hot environment on executive functioning capabilities of healthy individuals.
  
  
  METHODS
  In this prospective laboratory study, 40 healthy male and female subjects 18 to 45 years of age performed treadmill exercise while wearing athletic clothing and a backpack in either a hot or temperate environment. Vital signs, core and skin temperature, and perceptual measures (thermal sensation, sweating, comfort, and perceived exertion) were measured before, during, and after the treadmill test. Cognitive function was measured before and after the treadmill test using the Wisconsin Card Sorting Test (WCST) and a Psychomotor Vigilance Test (PVT).
  
  
  RESULTS
  Subjects in the hot condition reached a similar core temp of 38.2° ± 0.5°C vs 37.7° ± 0.3°C (P = .325) in the temperate group but had a higher heart rate (P < .001) and skin temperature (P < .001). Hot and normal temperature groups did not differ in their PVT performance. There were more correct responses (P < .001), fewer errors (P < .001), and more conceptual responses (P = .001) on the WCST after exertion in both the hot room and normal temperature room conditions. Perseverations and perseverative errors (P = .002) decreased in both groups after exertion.
  
  
  CONCLUSIONS
  Conditions of mild heat stress coupled with modest rehydration and short hiking treks do not appear to negatively affect executive function or vigilance.
authors.affiliation: Department of Emergency Medicine, Emergency Responder Human Performance Lab, University of Pittsburgh, Pittsburgh, PA.
authors.forename: Sarah M
authors.initials: SM
authors.lastname: Parker
authors.forename: Jennifer R
authors.initials: JR
authors.lastname: Erin
authors.forename: Riana R
authors.initials: RR
authors.lastname: Pryor
authors.forename: Priya
authors.initials: P
authors.lastname: Khorana
authors.forename: Joe
authors.initials: J
authors.lastname: Suyama
authors.forename: Frank X
authors.initials: FX
authors.lastname: Guyette
authors.forename: Steven E
authors.initials: SE
authors.lastname: Reis
authors.forename: David
authors.initials: D
authors.lastname: Hostler
mesh_terms: D000293:Adolescent; D000328:Adult; D001833:Body Temperature Regulation / Q000502:physiology; D056344:Executive Function / Q000528:radiation effects*; D015444:Exercise / Q000502:physiology*; D005260:Female; D006339:Heart Rate; D018882:Heat Stress Disorders / Q000209:etiology / Q000503:physiopathology; D006358:Hot Temperature / Q000009:adverse effects*; D006801:Humans; D008297:Male; D008875:Middle Aged; D005082:Physical Exertion / Q000502:physiology; D013997:Time Factors; D055815:Young Adult
keywords: attention; heat stress; hiking; hyperthermia; reaction time