Hiker Heat Risk Study: The Relation Between Physiological Measurements And Self-Reported Risk Perception And Risk-Taking While Hiking In A Hot And Dry Environment

The Phoenix area trail system rescues over 200 hikers every year due to extreme levels of heat. Although much is known about how hyperthermia and dehydration affect a person physically, little is known about how this affects an individual’s risk-taking (RT) and risk perception (RP). This study aimed to assess how individual fitness, hydration, body temperature, and subjective feelings of heat, thirst, and physical exertion affected their ability to perceive risk. Three-hundred-nineteen participants were recruited at the Piestewa Peak trailhead in Phoenix Arizona and an additional 21 were recruited as a less active cohort to hike A-Mountain, also in Phoenix (42.9% female, 40.1±12.9 years). Individuals who completed or hiked at least 30 minutes and were greater than eighteen years of age were considered for this study. Participants were asked to complete a 39-part questionnaire assessing their RP, RT behaviors, and the subjective feelings of thirst, heat, and exertion during their hike. Physiological measures, including VO2Max estimates (via submaximal step-tests), urine specific gravity (USG), and body temperature were taken. High and low RP groups were created based on the median RP score as were high and low VO2Max, body temperature and USG groups. Individuals who were more fit reported lower RP scores X2 (1, N = 132) = 7.758, p = 0.005. Those who reported more perceived heat or thirst reported higher RP scores F(3, 329) = 4.843, p = 0.003 and F(6, 626) = 2.635, p = 0.016. Body temperature results were significant for some tests but insignificant for others showing a trend towards an effect on RT F(1, 114) = 5.278, p = 0.023) and X2 (1, N = 116) = 3.515, p = 0.061. These results show high fitness level may cause an individual to perceive less risk while ii increased feelings of heat or thirst concomitantly increase an individual’s RP score. Although insignificant (p = 0.062), thermal state (body temperature) may influence an individual’s propensity for risk.