EFFECTS OF PHYSICAL ACTIVITY OR EXERCISE ON CARDIOVASCULAR PARAMETERS AND OXIDATIVE STRESS IN RATS

Abstract

The purpose of this study was to determine if access to physical activity or exercise affects select cardiovascular parameters and oxidative stress biomarkers. Male Sprague-Dawley rats were separated into three groups (n = 24): having no access to physical activity outside of the cage, having access to twice weekly physical activity in a large box, and having regular exercise on a running wheel. Resting blood pressure and heart rate were monitored weekly. At week 20 of the study, blood samples were collected from a total of thirty-six rats, 12 from each group. Glutathione (GSH), oxidized glutathione (GSSG), triglycerides (TG), high density lipoproteins (HDL), and low density lipoproteins (LDL) were measured in whole blood; oxygen radical absorbance capacity (ORAC) was measured in plasma samples. ORAC did not differ among the 3 groups. GSH was lower in the no-physical activity group (p < 0.05) compared to other groups. GSSG:GSH was similar in all groups. TG and LDL were lowest in the exercise (98.4 +11, 19.5+2.1 mgòdl-1) compared to no-physical activity (139+12.4, 27.8+2.5òdl-1) and physical activity (151.3+9.2, 30.3+1.8òdl-1) groups (p < .05). HDL was unexpectedly lower in the exercise group. Over time, SBP declined and was lowest in the exercise group (week 13:SBP = 129.1 mmHg, MAP = 103.8 mmHg, DBP= 90.4 mmHg, p < .05), followed by intermittent switching between the physical activity and no-physical activity and no-physical activity groups, with mean SBP > 140 mmHg. This data shows that running exercise every other day reduces blood pressure. Regular wheel running exercise was associated with healthier levels of blood lipids in comparison to either animals with access twice- weekly physical activity or no regular physical activity. Finally, regular running exercise was associated with increased GSH, implying greater antioxidant protection. However, there was no alteration in antioxidant capacity and no change in redox balance from either physical activity or regular exercise.