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Psychological Stress-Induced DNA Damage in Lymphocytes of Aerobically Fit and Unfit Individuals

Zilles, Kelly Jean (2007) Psychological Stress-Induced DNA Damage in Lymphocytes of Aerobically Fit and Unfit Individuals. Master's Thesis, University of Pittsburgh. (Unpublished)

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Habitual aerobic exercise has a beneficial effect on many systems of the body and reduces the risk of developing certain diseases, including cardiovascular disease and some cancers. Psychological stress, which has some of the same physiological effects, has a negative influence on several systems, including immune and neuroendocrine functioning. It is possible that exercise serves to combat the detrimental effects of stress by buffering its harmful influences. The primary aim of this study was to examine one potential protective mechanism: the increased resistance of cells to stress-induced oxidative damage as a result of aerobic exercise training. In order to accomplish this, a 2 (Group assignment: stress/nonstressed) x 3 (Time: baseline/ immediately post-stressor/20 minutes post-stressor) experimental design was used. Forty participants were assigned to either a stressed experimental group or a nonstressed control group. Participants in the stress group were exposed to experimental tasks that typically cause acute stress. Oxidative damage was measured at each time point by scoring the amount of DNA damage in lymphocytes isolated from the blood. Repeated measures analysis of covariance (ANCOVA) and hierarchical multiple regression were performed to examine the differences in lymphocyte DNA damage in response to acute psychological stress in participants of varying cardiorespiratory fitness levels. It was hypothesized that group assignment would significantly influence the rise in DNA damage, indicating that the stressful tasks induced the damage. The ANCOVA supported this expectation, F(1,38) = 4.1, p<0.05, partial eta2 = 0.10, however, the regression analysis did not find that fitness levels significantly interacted with group assignment to buffer the effect of stress on DNA damage. These results should be interpreted with caution because of the small sample size and the limited variability of cardiorespiratory fitness levels in the sample. Future studies are needed to address these limitations and broaden the knowledge of how physical fitness can protect from the potentially damaging effects of psychological stress.


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Item Type: University of Pittsburgh ETD
Status: Unpublished
CreatorsEmailPitt UsernameORCID
Zilles, Kelly Jeankjz3@pitt.eduKJZ3
ETD Committee:
TitleMemberEmail AddressPitt UsernameORCID
Committee ChairBaum, Andrew
Committee MemberCaggiula, Anthony
Committee MemberJakicic, John
Date: 19 September 2007
Date Type: Completion
Defense Date: 23 July 2007
Approval Date: 19 September 2007
Submission Date: 6 August 2007
Access Restriction: No restriction; Release the ETD for access worldwide immediately.
Institution: University of Pittsburgh
Schools and Programs: Dietrich School of Arts and Sciences > Psychology
Degree: MS - Master of Science
Thesis Type: Master's Thesis
Refereed: Yes
Uncontrolled Keywords: antioxidants; DNA; exercise; fitness; oxidative stress; psychological stress
Other ID:, etd-08062007-085401
Date Deposited: 10 Nov 2011 19:57
Last Modified: 15 Nov 2016 13:48


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