Oxidative Stress Response to Short Duration Bout of Submaximal Aerobic Exercise in Healthy Young Adults

The purpose of this study was to investigate the oxidative stress response to a short duration bout of submaximal exercise in a cohort of healthy young adults. 15 apparently healthy college age males and females completed a modified Bruce-protocol treadmill test to 75–80% of their heart rate reserve. Blood samples collected immediately before (pre-exercise), immediately after, 30, 60 and 120 minutes post-exercise were assayed for total antioxidant capacity (TAC), superoxide disumutase (SOD), thiobarbituric acid-reactive substances (TBARS), and protein carbonyls (PC). SOD activity was significantly increased from pre-exercise levels at 30 minutes (77%), 60 minutes (33%), and 120 minutes (37%) post-exercise. TAC levels were also significantly increased from pre-exercise levels at 60 minutes (30%) and 120 minutes (33%) post-exercise. There were no significant changes in biomarkers for reactive oxygen/nitrogen species (RONS) mediated damage (TBARS and PC) across all post-exercise time points. In a cohort of healthy young adults, a short duration bout of submaximal aerobic exercise elicited increases in antioxidant activity/concentration, but did not evoke changes in oxidative stress-induced damage. These results may suggest that: (1) short duration bouts of submaximal aerobic exercise are sufficient to induce RONS generation; and (2) the antioxidant defense system is capable of protecting against enhanced RONS production induced by a short duration, submaximal exercise bout in healthy young adults

Oxidative stress response to short duration bout of submaximal aerobic exercise in healthy young adults

The purpose of this study was to investigate the oxidative stress response to a short duration bout of submaximal exercise in a cohort of healthy young adults. 15 apparently healthy college age males and females completed a modified Bruce-protocol treadmill test to 75-80% of their heart rate reserve. Blood samples collected immediately before (pre-exercise), immediately after, 30, 60 and 120 minutes post-exercise were assayed for total antioxidant capacity (TAC), superoxide disumutase (SOD), thiobarbituric acid-reactive substances (TBARS), and protein carbonyls (PC). SOD activity was significantly increased from pre-exercise levels at 30 minutes (77%), 60 minutes (33%), and 120 minutes (37%) post-exercise. TAC levels were also significantly increased from pre-exercise levels at 60 minutes (30%) and 120 minutes (33%) post-exercise. There were no significant changes in biomarkers for reactive oxygen/nitrogen species (RONS) mediated damage (TBARS and PC) across all post-exercise time points. In a cohort of healthy young adults, a short duration bout of submaximal aerobic exercise elicited increases in antioxidant activity/concentration, but did not evoke changes in oxidative stress-induced damage. These results may suggest that: (1) short duration bouts of submaximal aerobic exercise are sufficient to induce RONS generation; and (2) the antioxidant defense system is capable of protecting against enhanced RONS production induced by a short duration, submaximal exercise bout in healthy young adults

Increased Nitric Oxide and Attenuated Diastolic Blood Pressure Variability in African Americans with Mildly Impaired Renal Function

We investigated the relationship between renal function, blood pressure variability (BPV), and nitric oxide (NO) in a group of African Americans with normal or mildly impaired renal function. 24-hour ambulatory blood pressure monitoring was performed, NO measured, and glomerular filtration rate (GFR) calculated in 38 African Americans. Participants were categorized as having normal (GFR > 90 mL/min per 1.73 m2) or mildly impaired (GFR 60–89 mL/min per 1.73 m2) renal function. Diastolic BPV was significantly lower in the mildly impaired renal function group. Regression analyses revealed a significant positive association between GFR and diastolic BPV for the entire study group. Plasma NO levels were significantly higher in the mildly impaired renal function group and negatively correlated with diastolic BPV. In conclusion, diastolic BPV was reduced in African Americans with mildly impaired renal function, which may be the result of increased NO production. These results conflict with previous findings in diseased and nonblack populations and could provide rationale for studying BPV early in the disease state when BP-buffering mechanisms are still preserved

Effects of Moderate Aerobic Exercise Training on Vascular Health and Blood Pressure in African Americans

As healthcare progresses toward individualized medicine, understanding how different racial groups respond to lifestyle interventions is valuable. It is established that African Americans have disproportionate levels of cardiovascular disease and impaired vascular health, and clinical practice guidelines suggest lifestyle interventions as the first line of treatment. Recently, the authors reported that 6 months of aerobic exercise improved inflammatory markers, flow-mediated dilation (FMD), and levels of circulating endothelial microparticles (EMPs) in African American adults. This study is a subgroup analysis of the aerobic exercise–induced changes in vascular health and blood pressure (BP) measures, including carotid artery intima-media thickness (IMT), nitroglycerin-mediated dilation (NMD), ambulatory BP, and office BP. Sedentary African American adults (53.4±6.2 years; 21 women and 5 men) showed improved vascular health but no change in BP. Carotid artery IMT decreased 6.4%, plasma nitric oxide levels increased 76.6%, plasma EMP levels decreased, percentage of FMD increased 59.6%, and FMD/NMD ratio increased 36.2% (P<.05 for all). Six months of aerobic exercise training is sufficient to elicit improvements in vascular structure and function in African Americans, even without improvements in BP measures or NMD (ie, smooth muscle function). To our knowledge, this is the first study to report such findings in African Americans

Effects of Moderate Aerobic Exercise Training on Vascular Health and Blood Pressure in African Americans

As healthcare progresses toward individualized medicine, understanding how different racial groups respond to lifestyle interventions is valuable. It is established that African Americans have disproportionate levels of cardiovascular disease and impaired vascular health, and clinical practice guidelines suggest lifestyle interventions as the first line of treatment. Recently, the authors reported that 6 months of aerobic exercise improved inflammatory markers, flow-mediated dilation (FMD), and levels of circulating endothelial microparticles (EMPs) in African American adults. This study is a subgroup analysis of the aerobic exercise–induced changes in vascular health and blood pressure (BP) measures, including carotid artery intima-media thickness (IMT), nitroglycerin-mediated dilation (NMD), ambulatory BP, and office BP. Sedentary African American adults (53.4±6.2 years; 21 women and 5 men) showed improved vascular health but no change in BP. Carotid artery IMT decreased 6.4%, plasma nitric oxide levels increased 76.6%, plasma EMP levels decreased, percentage of FMD increased 59.6%, and FMD/NMD ratio increased 36.2% (P<.05 for all). Six months of aerobic exercise training is sufficient to elicit improvements in vascular structure and function in African Americans, even without improvements in BP measures or NMD (ie, smooth muscle function). To our knowledge, this is the first study to report such findings in African Americans

Endothelial Activation Microparticles and Inflammation Status Improve with Exercise Training in African Americans

African Americans have the highest prevalence of hypertension in the world which may emanate from their predisposition to heightened endothelial inflammation. The purpose of this study was to determine the effects of a 6-month aerobic exercise training (AEXT) intervention on the inflammatory biomarkers interleukin-10 (IL-10), interleukin-6 (IL-6), and endothelial microparticle (EMP) CD62E+ and endothelial function assessed by flow-mediated dilation (FMD) in African Americans. A secondary purpose was to evaluate whether changes in IL-10, IL-6, or CD62E+ EMPs predicted the change in FMD following the 6-month AEXT intervention. A pre-post design was employed with baseline evaluation including office blood pressure, FMD, fasting blood sampling, and graded exercise testing. Participants engaged in 6 months of AEXT. Following the AEXT intervention, all baseline tests were repeated. FMD significantly increased, CD62E+ EMPs and IL-6 significantly decreased, and IL-10 increased but not significantly following AEXT. Changes in inflammatory biomarkers did not significantly predict the change in FMD. The change in significantly predicted the change in IL-10. Based on these results, AEXT may be a viable, nonpharmacological method to improve inflammation status and endothelial function and thereby contribute to risk reduction for cardiovascular disease in African Americans

Adherence to Exercise Prescription and Improvements in the Clinical and Vascular Health of African Americans

Improvements in indices of vascular health and endothelial function have been inversely associated with hypertension, a risk factor for cardiovascular disease (e.g., myocardial infarction, stroke, and heart failure), renal failure, and mortality. Aerobic exercise training (AEXT) has been positively associated with improvements in clinical health values, as well as vascular health biomarkers, and endothelial function. The purpose of this study was to evaluate whether measures of exercise adherence were related to clinical outcome measures and indices of vascular health subsequent to a 6-month AEXT intervention in a middle-to-older aged African American cohort. Following dietary stabilization, sedentary, apparently healthy, African American adults (40 - 71 y/o) underwent baseline testing including blood pressure, flow-mediated dilation (FMD) studies, fasting blood sampling, and graded exercise testing. Upon completion of a supervised 6-month AEXT intervention, participants repeated all baseline tests. Exercise adherence was measured three ways: exercise percentage, exercise volume, and exercise score. There were no significant correlations between the changes in the vascular health biomarkers of the participants and any of the adherence measures. In addition, there were no significant correlations between any of the adherence measures and the clinical values of the participants that had been significantly changed pre-post-AEXT. Participants improved their clinical and vascular health and decreased risk factors for hypertension and cardiovascular disease regardless of their level of adherence to AEXT. Future studies should continue to accurately quantify adherence in order to assess the exercise dose for improvements in vascular and clinical health

Effects of Training Status on Time Course Oxidative Stress Response to a Sub-maximal Exercise Test

Previous studies have reported inconsistent results on the effects of training status on the oxidative stress time course response to acute exhaustive exercise. Because exhaustive exercise to volitional fatigue is not commonplace for most exercise sessions in the general public, we sought to determine the influence of training status on the time course response of oxidative stress biomarkers to a sub-maximal exercise test

Differentiating Racial Differences in Time-Course Oxidative Stress Responses to Acute Exercise

African Americans (B) are disproportionately hypertensive with reports of greater cardiovascular disease (CVD) incidence. Oxidative stress is associated with the development of CVD, and B have greater levels of oxidative stress than other ethnic groups, in particular Caucasians (W)

Racial Differences in the Time-Course Oxidative Stress Responses to Acute Exercise

African Americans have disproportionate levels of cardiovascular disease and oxidative stress. The purpose of our study was to examine racial differences between African American and Caucasian adults in time-course oxidative stress responses to a treadmill test. After a 12-hr fast, 18 participants (9 of each ethnic group; 21 ± 0.4 yrs) completed a submaximal treadmill test and underwent serial blood draws: Pre, Post (within 2 min), 30, 60, and 120 min after exercise. At each time-point, superoxide dismutase (SOD, U/mL), total antioxidant capacity (TAC, mM), protein carbonyls (PC, nmol/mg), and thiobarbituric acid-reactive substance (TBARs, μmol/L) were measured. We found no difference between groups for blood pressure, BMI, or exercise capacity (as measured by volume of oxygen consumed, VO2 max). African Americans had significantly (p \u3c 0.05) higher SOD (Pre: 5.45 ± 0.4 vs. 3.69 ± 0.69; 60 min: 8.99 ± 0.7 vs. 4.23 ± 0.6; 120 min: 9.69 ± 1.6 vs. 3.52 ± 0.7), TAC (Pre: 2.31 ± 0.25 vs. 1.16 ± 0.3; Post: 2.39 ± 0.2 vs. 1.34 ± 0.2; 30 min: 2.29 ± 0.2 vs. 1.09 ± 0.2), and PC (Pre: 1.09 ± 0.1 vs. 0.82 ± 0.1; Post: 1.14 ± 0.1 vs. 0.81 ± 0.1; 30 min: 1.13 ± 0.1 vs. 0.85 ± 0.1; 60 min: 1.06 ± 0.1 vs. 0.81 ± 0.05), but not TBARs. Between groups, only SOD exhibited a different time-course response: levels for African Americans rose steadily throughout the 120 min, while levels for Caucasians peaked at 30 min and by 120 min had returned to pre-exercise levels. Race had a greater effect on oxidative stress responses than submaximal exercise did. African Americans had significantly higher TAC, SOD, and PC levels compared to Caucasians