Date of Graduation

8-2014

Document Type

Thesis

Degree Name

Master of Science in Kinesiology (MS)

Degree Level

Graduate

Department

Health, Human Performance and Recreation

Advisor

Brendon McDermott

Committee Member

Matthew Ganio

Second Committee Member

Matthew Ganio

Third Committee Member

Stavoros Kavouras

Keywords

Air, Breathing, Cool, Cycling, Effects, Heat

Abstract

INTRODUCTION: The purpose of this study was to establish the ability of the Core Cooler device to prevent rises in physiological heat strain of trained male cyclists during cycling exercise in the heat. METHODS: 15 healthy male cyclists cycled at 50-70% VO2max for 75 minutes in a heat chamber of 31°C & 55% RH while breathing through the Core Cooler device under three different conditions: 1:4 ratio without ice termed control (CN), 1:4 ratio with ice termed low intermittent (LI), and at 1:1 ratio with ice termed high intermittent (HI). Data collected every 15 minutes assessing intestinal temperature (TGI), heart rate (HR), physiological strain index (PSI), blood pressure (BP), mean skin temperature (TSK), and perception of thirst, thermal sensation, and rate of perceived exertion, inspired air temperature, ambient temperature and relative humidity in all trials. VO2 workload and respiratory rates (RR) recorded three times at evenly spaced time points (12.30, 42.30, 1.12.30), during all trials respectively. Statistical significance was set at a p value of 0.05 and measured using repeated measures ANOVA and post hoc t-test. RESULTS: No statistically significant differences in diet, USG, temperature, %RH, VO2 workload, or RR were found between any trial. Inspired air temperature averaged significantly different between CNvsLI & CN¬vsHI (p<0.01, CN 30.92±0.35°C, LI 19.81±0.44°C, & HI 19.28±0.72°C), but not between LIvsHI (p=1.000). Physiological responses between trials found insignificant differences. TGI produced significant interactions between trials (p = 0.033) averaging CN 37.86±0.02°C, LI 37.91±0.10°C, & HI 37.80±0.07°C, but post hoc analysis provided no difference between any time or trial (p>0.05). HR (p=0.103), systolic BP (n=11, p = 0.102), diastolic BP (n=11, p = 0.190), TSK (n=5, p=0.464), thirst (p=0.773), thermal sensation (p=0.709), and RPE (p=0.669) were not significantly different between trials. CONCLUSION: Modifications to the Core Cooler device are needed providing greater inhalation capabilities of cool air during exercise in the heat for significant attenuation of physiological heat strain. The Core Cooler in its current form will not provide an adequate prevention to heat illness, prolong endurance capabilities, or enhanced performance to a significant degree. This research was funded by Core Cooler Company, LLC.

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