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Description
More than 200 hikers are rescued annually in the greater Phoenix area. This study
examined the impact of hiking in hot (HOT), dry temperatures versus moderate (MOD)
temperatures on dietary intake behaviors as well as markers of heat stress. Twelve
recreational mountain hikers climbed “A” Mountain four consecutive times (4-miles) on
a HOT day (WBGT=31.6 °C) and again on a MOD day (WBGT= 19.0 °C). Simulated
food and fluid behavior allowed participants to bring what they normally would for a 4-
mile hike and to consume both ad libitum. The following heat stress indicators (mean
difference; p-value), were all significantly higher on the HOT hike compared to the MOD
hike: average core temperature (0.6 °C; p=0.002), average rating of perceived exertion
(2.6; p=0.005), sweat rate (0.54; p=0.01), and fluid consumption (753; p<0.001). On the
HOT hike, 42% of the participants brought enough fluids to meet their individual
calculated fluid needs, however less than 20% actually consumed enough to meet those
needs. On the MOD hike, 56% of participants brought enough fluids to meet their needs,
but only 33% actually consumed enough to meet them. Morning-after USG samples
≥1.020 indicating dehydration on an individual level showed 75% of hikers after the
HOT hike and 67% after the MOD hike were unable to compensate for fluids lost during
the previous day’s hike. Furthermore, participant food intake was low with only three
hikers consuming food on the hot hike, an average of 33.2g of food. No food was
consumed on the MOD hike. These results demonstrate that hikers did not consume
enough fluids to meet their needs while hiking, especially in the heat. They also show
heat stress negatively affected hiker’s physiological and performance measures. Future
recommendations should address food and fluid consumption while hiking in the heat.
examined the impact of hiking in hot (HOT), dry temperatures versus moderate (MOD)
temperatures on dietary intake behaviors as well as markers of heat stress. Twelve
recreational mountain hikers climbed “A” Mountain four consecutive times (4-miles) on
a HOT day (WBGT=31.6 °C) and again on a MOD day (WBGT= 19.0 °C). Simulated
food and fluid behavior allowed participants to bring what they normally would for a 4-
mile hike and to consume both ad libitum. The following heat stress indicators (mean
difference; p-value), were all significantly higher on the HOT hike compared to the MOD
hike: average core temperature (0.6 °C; p=0.002), average rating of perceived exertion
(2.6; p=0.005), sweat rate (0.54; p=0.01), and fluid consumption (753; p<0.001). On the
HOT hike, 42% of the participants brought enough fluids to meet their individual
calculated fluid needs, however less than 20% actually consumed enough to meet those
needs. On the MOD hike, 56% of participants brought enough fluids to meet their needs,
but only 33% actually consumed enough to meet them. Morning-after USG samples
≥1.020 indicating dehydration on an individual level showed 75% of hikers after the
HOT hike and 67% after the MOD hike were unable to compensate for fluids lost during
the previous day’s hike. Furthermore, participant food intake was low with only three
hikers consuming food on the hot hike, an average of 33.2g of food. No food was
consumed on the MOD hike. These results demonstrate that hikers did not consume
enough fluids to meet their needs while hiking, especially in the heat. They also show
heat stress negatively affected hiker’s physiological and performance measures. Future
recommendations should address food and fluid consumption while hiking in the heat.
ContributorsPelham, Emily Claire (Author) / Wardenaar, Floris (Thesis advisor) / Whisner, Corrie (Committee member) / Levinson, Simin (Committee member) / Arizona State University (Publisher)
Created2020