Date of Award

Summer 8-2018

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

Kinesiology, Health, and Sport Science

First Advisor

Hayden D. Gerhart, Ph.D.

Second Advisor

Madeline P. Bayles, Ph.D.

Third Advisor

Kristi L. Storti, Ph.D.

Fourth Advisor

Robert Alman, D.Ed.

Fifth Advisor

Yongsuk Seo, Ph.D.

Abstract

PURPOSE: The purpose of the present study is to observe the impact of a hyperthermic environment on physiological responses in EMT students performing a simulated occupational task. METHODS: Ten IUP EMT Students currently enrolled in the EMT Training course at the IUP Institute of Rural Safety and Health participated in the present study. Participants reported to 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 participants returned to the laboratory for their first of two-exercise session. The environmental condition (hyperthermic and normothermic) was assigned in counterbalanced fashion. 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. Participants 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 desired intensity. Immediately following the treadmill walk, participants immediately transitioned to a sandbag (50 lb.) lift from the ground to a table (72in x 28.5in). Participants lifted the sandbag to a metronome. Participants 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, participants transitioned back to the treadmill to repeat the 10-minute walk at 70%-80% maximum heart rate. Once again, after the treadmill walk, participants transitioned directly to the sandbag lift for 5 minutes. Upon completion of the second sandbag lift, participants passively recovered in a seated position outside of the environmental chamber. Following 10 minutes of passive recovery all variables were reassessed. This concluded the study protocol. Participants 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, participants 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 main effect of time was found for heart rate (HR) (p = 0.006), mean arterial pressure (MAP) (p = 0.024), rating of perceived exertion (RPE) (p = 0.035), oxygen consumption (VO2) (p = 0.009), thermal sensation (TSS) (p = 0.051), core temperature (p = 0.022), mean skin temperature (MST) (p = 0.000) and mean body temperature (MBT) (p = 0.003). A main effect of condition was found for HR (p = 0.001), RPE (p = 0.004), TSS (p = 0.000), core temperature (p = 0.033), MST (p = 0.015) and MBT (p = 0.010). A significant time by condition interaction was seen in TSS (p = 0.043) and MST (p = 0.033) CONCLUSION: A hyperthermic environment causes significant changes to physiological response to exercise. EMT students were able to complete the occupational stress when an intensity of 70%-80% HR max was maintained. The high intensity nature of EMS work requires a higher level of physical fitness to succeed in the occupation. Fitness and nutritional information should be provided and encouraged for all first responders.

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