Exercise-induced oxidative stress markers (glutathione and oxidized LDL) during and after an hour of aerobic exercise

UNCG Author/Contributor (non-UNCG co-authors, if there are any, appear on document)
Junyong Lee (Creator)
Institution
The University of North Carolina at Greensboro (UNCG )
Web Site: http://library.uncg.edu/
Advisor
Allan Goldfarb

Abstract: Exercise puts a stress on the body and results in multiple physiological changes despite the homeostatic mechanisms in place that try to maintain normalized conditions in the body. One of the factors that are transiently elevated with exercise of sufficient intensity and duration is the production of reactive oxygen/nitrogen species (RONS) which act as signal molecules that can influence adaptation. If these RONS accumulate beyond the normal level this is known as oxidative stress (OS). If OS is maintained over time, then homeostasis may be disrupted and adverse responses may occur, leading to dysfunction or disease. Previous studies have reported that most types of exercise (resistance, aerobic, and/or high intensity interval trainings) can induce an acute OS. The literature suggests that sufficient intensity and duration of exercise are needed to increase OS during exercise and is often noted with sample taken immediately after the exercise. Aerobic activities of at least 65-70%VO2max for at least 10 minutes have reported increased OS based on blood and/or muscle markers. Unfortunately, most studies only determined immediate post exercise responses. Only one study has reported a time-course of OS immediately after exercise and the sample period ended 30 minutes after exercise. However, no study has examined the timeline of OS biomarkers during and after an exercise. Additionally, there is limited information dealing with evening exercise. In this study, two OS markers were determined: lipid oxidation marker (oxidized low-density lipoprotein, LDLox) and the antioxidant glutathione and its status (glutathione status; the ratio of oxidized glutathione (GSSG), to total glutathione, TGSH [GSSG/TGSH]. The purposes of this study were 1) to determine the time course accumulation in the blood markers over the 1-hour exercise and 2) to determine the time course of the removal of OS blood markers in the 1 hour after exercise. To accomplish these objectives, 10 subjects participated in two conditions. The exercise condition contained an exercise and recovery period. The exercise period was one hour of aerobic exercise in an environmental chamber, which was set at 30? and 40% humidity. The recovery period was two 30-minute periods (30mins in the chamber and 30mins outside of the chamber). The temperature outside of the chamber was between 20-23? with 30-40% humidity. The control condition was composed of a non-exercise seated position as was the recovery period. The recovery period was the same as the exercise condition, but for the first 30 minutes inside the chamber and the next 30 minutes was outside the chamber. Blood collection started 15mins before exercise and continued every 15mins until the end of the one- hour recovery period (total of 9 blood samples per visit per subject). The exercise condition did not show significantly increased plasma LDLox concentration and whole blood GSSG/TGSH ratio compared to the rested condition in the hot conditions. This appears to be related to the hot condition which showed GSSG/TGSH increased dramatically by 30 minutes in both conditions. Thus, there was only a time significance (p=0.02). The level of OS approached significance for LDLox for condition p=0.054. The time effect also approached significance at p=0.061 and there was no significant interaction effect at a p= 0.074. Although the LDLox appeared elevated there were large interindividual differences between subjects. The pattern for the LDLox over time was fairly stable over the last 30 minutes of the exercise bout. In contrast, GSSG/TGSH ratio fluctuated over the 60-minute time frame in the hot condition. During the recovery period, the level of the two OS markers did not show the anticipated trend toward baseline levels. In fact, GSSG/TGSH showed significant increases at the 120min time point p=0.04 independent of condition. In summary, the data suggests that these oxidative stress markers responded differently over the time course. The GSSG/TGSH ratio fluctuated more than the LDLox. Due to the fact that the intensity of exercise was lowered the OS markers did not obtain a significant change by the exercise compared to the resting condition. The cycling at 70-75% of maximum power initially induced enough stress but when the intensity was lowered to ~ 51% the stress and was not sustained. In addition, the 30?-chamber temperature most likely affected the results as the GSSG/TGSH ratio increased at 30 minutes independent of exercise. It is suggested that future studies examine more neutral environmental control conditions in future studies with a larger sample size. [This abstract may have been edited to remove characters that will not display in this system. Please see the PDF for the full abstract.]

Additional Information

Publication
Thesis
Language: English
Date: 2021
Keywords
Aerobic exercsie, Exercise, Glutathione, LDLox, Lipid peroxidation, Oxidative stress
Subjects
Oxidative stress
Aerobic exercises
Low density lipoproteins
Glutathione

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