Influence of Perceived Stress in Human Lymphocytes DNA Damage: The Role of Habitual Physical Activity in Attenuating Stress and/or Reducing DNA Damage

Introduction Stress is the result of several factors, such as work demands, fatigue, sleep, diet and others. Psychological stress depends not only on the magnitude and density of the stress factors, but also from subject’s perception of his/her own capacities to deal with each situations. Psychological stress has been proposed as an important factor in the pathogenesis and development of several diseases, and in cancer¹. Oxidative DNA damage has been used to estimate cancer risk, once it causes mutagenesis and carcinogenesis². A few studies tried to establish the link between psychological stress, biochemical changes, oxidative stress and DNA oxidative damaged. On the other hand, it has been proposed that an active lifestyle is associated with an increased organism protection to oxidative stress, and an increase in the ability to develop psychological strategies of coping with stress events. The aim of the present study was to analyze the influence of daily perceived stress on DNA damage and to verify the possible role of physical activity in reduction of DNA damage and perceived stress.

Methods Thirty healthy men, nonsmokers, above 40 years old, integrated this study. 15 of these subjects had a moderate to vigorous daily physical activity and the remaining ones had sedentary to lower daily physical activity, according to the levels proposed by the ACSM³.Psychological stress was measured through Perceived stress scale (PSS). Daily physical activity was measured during at least 4 days to 7 days with an accelerometer (ActiGraph). Oxidative DNA damage was quantified by comet assay with FPG enzyme⁴. T-test for independent samples were used to analyze differences between groups, and significant level was set at p

Results/Discussion Our results revealed that the most active subjects exhibited lower perception of stress and oxidative damage to DNA. Habitual physical activity induces an increase in endurance capacity, increasing capacity to deal with higher daily workloads and induce hormonal changes associated with an increase in sleep quality and general relaxed state; we believe that higher physical activity contributes to enhance coping abilities to deal with stress events. Moreover, regular physical activity is also related with a decrease of oxidative damage to DNA, possible due to an decrease in oxidant state, but also to the reduction of biochemical changes associated with hormonal changes.

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