Influence of exercise intensity on endogenous oxidative stress and antioxidant capacity

Parker, L., McGuckin, T., and Leicht, A. (2012) Influence of exercise intensity on endogenous oxidative stress and antioxidant capacity. Supplement to Journal of Science and Medicine in Sport, 15 (Suppl. 1). 32. pp. 18-19.

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Introduction: Regular physical activity and exercise are commonly used as an effective treatment for numerous diseases and general poor health. While the health benefits of engaging in regular physical activity are well known, an ideology gaining momentum in recent years has been that certain intensities may elicit a negative physiological effect through exercise induced oxidative stress (EIOSI). While previous research has paved the way to understanding EIOS stress at a superficial level, the relationship between exercise sub-components such as intensity and EIOS remain far more elusive. Therefore, the aim of the current study was to examine the influence of exercise intensity on EIOS including antioxidant capacity.

Methods: Non-smoking, untrained healthy adult males (n=14) participated in two exercise sessions using an electronically braked cycle ergometer. The first session consisted of a graded exercise test to determine maximal power output and oxygen consumption (VO₂max). One week later, participants undertook 5 minute cycling bouts at 40% VO ₂max, 55% VO₂max, 70% VO₂max, 85% VO₂max and 100% VO₂max, with a passive 12 minute rest between stages. Measures of EIOS including biological antioxidant capacity (BAP) and reactive oxygen metabolites (dROM), and heart rate, VO₂, blood lactate and physical exertion were assessed at rest and immediately following each exercise stage. Significant (p<0.05) comparisons between exercise bouts were compared using repeated measures ANOVA and post-hoc painwise comparisons with a Bonferroni correction.

Results: Increasing exercise intensity significantly augmented heart rate (P<0.001), VO₂ (p<0.001), blood lactate (p<0.001) and physical exertion (p<0.001) with no significant effect on dROM levels compared to resting values. In contrast, increasing exercise intensity resulted in a significantly greater BAP at 70% (p=0.009), 85% (p=0.005) and 100% (P=O.OOO) of VO₂max compared to resting levels.

Discussion: The current results indicate that exercise intensity significantly affects oxidative function with brief, moderate to high intensity exercise leading to a significant increase in the endogenous antioxidant defense system, possibly to counteract the EIOS. Subsequently, regular moderate to high intensity exercise may produce long term benefits via enhancement of the endogenous antioxidant defense system, possibly through the upregu!ation of endogenous antioxidant enzymes. Further, 5 minute bouts of increasing exercise intensity maybe an effective method for accumulating the recommended daily amount of physical activity in the general population without significant EIOS.

Item ID: 23950
Item Type: Article (Abstract)
ISSN: 1440-2440
Date Deposited: 22 Nov 2012 05:07
FoR Codes: 11 MEDICAL AND HEALTH SCIENCES > 1106 Human Movement and Sports Science > 110602 Exercise Physiology @ 100%
SEO Codes: 95 CULTURAL UNDERSTANDING > 9501 Arts and Leisure > 950199 Arts and Leisure not elsewhere classified @ 100%
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