Author

Austin Sabo

Date of Award

12-2019

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

Kinesiology, Health, and Sport Science

First Advisor

Hayden D. Gerhart

Second Advisor

Madeline P. Bayles

Third Advisor

Kristi L. Storti

Fourth Advisor

Yongsuk Seo

Fifth Advisor

Dennis Marsili

Abstract

PURPOSE: The purpose of the present study is to observe the impact of a hyperthermic environment on physiological responses in police cadets performing a simulated occupational task. METHODS: Ten Indiana University of Pennsylvania (IUP) police cadets currently enrolled in the Indiana University of Pennsylvania Police Academy participated in the present study. The cadets reported to the Human Performance Laboratory in the IUP Center for Sports Science Research and Education for the first visit, a familiarization session, in which signed consent, health history, and all resting anthropometrics were obtained. The familiarization session concluded with a maximal exercise test performed to determine the intensity for the subsequent simulated occupational task sessions. Following a minimum of 48 hours rest the subjects returned to the laboratory for their first of two-exercise sessions. The cadets underwent the exercise sessions in either a hyperthermic of thermoneutral environment. Both exercise sessions consisted of baseline values for body weight, urine specific gravity, heart rate, rating of perceived exertion (RPE), blood pressure, oxygen consumption (VO2), skin temperature, core temperature and thermal sensation (TSS), outside the chamber and once again immediately upon entering the environmental chamber for all variables except body weight and urine specific gravity. Following 30 minutes of acclimation to the environment all variables are reassessed. Subjects then completed a 10-minute treadmill walk at 70%-80% of their maximal heart rate. If a subject exceeded this range intensity was reduced to keep them at their defined relative intensity. Immediately following the treadmill walk, cadets immediately transitioned to a sandbag (50 lb.) lift from the ground to a table (72in x 28.5in). Subjects lifted the sandbag to a metronome. Subjects were given 10 seconds to lift the sandbag onto the table top, and another 10 seconds to return the sandbag to the floor. This was repeated over the course of 5 minutes, until 15 lifts were successfully completed. After the sandbag lift, subjects transitioned back to the treadmill to repeat the 10-minute walk at 70%-80% maximum heart rate. Once again, after the treadmill walk, subjects transitioned directly to the sandbag lift for 5 minutes. Upon completion of the second sandbag lift, the subject exited the chamber where they passively recovered in a seated position. Following the 10-minute passive recovery all variables were reassessed. This concluded the study protocol. Subjects were permitted to leave the laboratory once their heart rate fell within 20bpm of their initial resting value. Following a minimum of 48 hours rest, subjects returned to the laboratory for the second exercise session. RESULTS: A two condition by nine time point analysis of variance (ANOVA) was conducted on all dependent variables. Post hoc analysis via paired samples t-test were conducted to further explain all main effects and interactions. A significant condition by time interaction was observed for respiratory exchange ratio (RER), blood lactate accumulation, Stroop Color Word Score: Mean Response Time, heart rate, rating of perceived exertion (RPE), thermal sensation (TSS), and core body temperature. CONCLUSION: It was observed that heart rate, rating of perceived exertion (RPE), respiratory exchange ratio (RER), blood lactate accumulation, thermal sensation (TSS), core body temperature, and mean response time were all significantly impacted by the hyperthermic environment. These impairments could result in a decrease in performance while on the job. In order to maintain adequate physiological and cognitive functioning there should be interventions implemented while in the academy to expose the cadets to environmental extremes and teach them how to function successfully in those extremes. The results from the present study displayed significant physiological and cognitive responses demonstrating what effect a hyperthermic environment has on various physiological and cognitive variables in police academy cadets.

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