Date of Graduation

8-2012

Document Type

Thesis

Degree Name

Bachelor of Science

Degree Level

Undergraduate

Department

Health, Human Performance and Recreation

Advisor/Mentor

Ganio, Matthew S.

Committee Member/Reader

Fort, Inza L.

Committee Member/Second Reader

Washington, Tyrone

Abstract

Context: Maintaining thermal balance under heat-stress depends on appropriate increases in sweating and skin blood flow (cutaneous vasodilation). Given the multiple effects on nicotine on the body, it is unknown if sweating and cutaneous vasodilation are impaired, or possibly enhanced in smokers during heat stress. Objective: To examine the effects of passive heating on thermoregulatory responses (i.e., sweating and cutaneous vasodilation) in smokers versus non-smokers. Design: 1 passive heat trial per subject. Patients or Other Participants: 14 male smokers (26 ± 7 y; 180.0 ± 5.5 cm; 81.2 ± 20.7 kg; 3.2 ± 1.9 packs/week) and 12 male non-smokers (26 ± 8 y; 172.4 ± 33.2 cm; 81.2 ± 20.7 kg) volunteered to participate. Intervention: Subjects were passively heated using a water perfused, tube-lined suit until core temperature (TC) increased 1.5°C from baseline. At baseline and each 0.5°C TC increase, core and skin temperatures (Tsk) were assessed. On an exposed forearm, skin blood flow (SKBF) via laser doppler flowmetry, local sweat rate (LSR), sweat gland output (SGO), and sweat gland activation (SGA). Data were analyzed via LabChart 8.0 and ImageJ. Statistical procedures were performed with SPSS v.20.0. Main Outcome Measures: SKBF, LSR, SGO, SGA, Tsk, and TC were all assessed via a two-way ANOVA. Sweat sensitivity, SKBF sensitivity, TC at sweat and SKBF onset, total body sweat-rate and percent body mass loss were all assessed via independent t-tests. Results: There were no significant differences in any measures between smokers and non-smokers (all p>0.05). TC and Tsk increased significantly (p<0.01) from baseline to 1.5°C TC increase (37.0 ± 0.3°C to 38.4 ± 0.2°C and 34.1 ± 0.5°C to 40.1 ± 0.4°C, respectively). Independent of group, SKBF, LSR, and SGO increased significantly (p<0.01) from baseline until TC increased 1.0°C (19.5 ± 13.6 to 65.3 ± 19.4% of max SKBF, 0.0 to 1.0 ± 0.5 mg∙cm-1∙min-1, and 0.0 to 9.2 ± 2.6 µg∙cm-1∙min-1, respectively). Other notable measures were TC at sweat onset (37.0 ± 0.3°C), total body sweat-rate (0.51 ± 0.21 L•hr-1), and percent body mass loss (-0.5 ± 0.1%). Conclusion: Passive heating similarly affected vasodilatory and sweating parameters in smokers and non-smokers. Therefore in these relatively young, male, light smokers, thermoregulation is neither hindered nor enhanced. Funding: This project was funded by the College of Education and Health Professions and Research & Sponsored Programs at the University of Arkansas and the Arkansas Biosciences Institute, the major research component of the Arkansas Tobacco Settlement Proceeds Act of 2000.

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