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Exercise training in aging: hemodynamic, metabolic, and oxidative stress evaluations
K L De Angelis1, A R Oliveira, A Werner
1Laboratory of Cardiovascular Physiology, Department of Physiology, University of Rio Grande do Sul, Brazil.
Hypertension (Dallas, Tex. : 1979)
|October 10, 1997
Summary
Exercise training in aged rats lowered resting heart rate and improved metabolic and oxidative stress responses. This suggests enhanced myocardial protection in trained versus sedentary aged rats.
Area of Science:
- Cardiovascular Physiology
- Gerontology
- Exercise Science
Background:
- The impact of exercise on cardiovascular and metabolic health in aging populations remains incompletely understood.
- Oxidative stress is a significant factor contributing to age-related cardiovascular decline.
- Previous studies on exercise training in aged individuals have yielded controversial results regarding its benefits.
Purpose of the Study:
- To investigate the effects of 11 weeks of treadmill exercise training on heart rate, mean arterial pressure, vasoreactivity, and plasma glucose and insulin levels in aged male Wistar rats.
- To evaluate the impact of exercise training on the heart's response to oxidative stress induced by hydrogen peroxide (H2O2).
Main Methods:
- Aged male Wistar rats were subjected to 11 weeks of treadmill exercise (1 h/d, 5 d/wk).
- Cardiovascular parameters (heart rate, mean arterial pressure) and vasoreactivity were measured.
- Plasma insulin and glucose levels were quantified using radioimmunoassay and colorimetric enzymatic assays.
- Oxidative stress was assessed by measuring thiobarbituric acid reactive substances (TBARS) in isolated, perfused hearts exposed to H2O2.
Main Results:
- Trained aged rats exhibited bradycardia (lower resting heart rate) compared to sedentary controls (298±7 vs. 336±16 bpm).
- Mean arterial pressure and vasoreactivity remained similar between trained and sedentary groups.
- The ratio of plasma insulin to glucose increased significantly in trained rats (6.9±0.7 vs. 3.5±0.4).
- The heart's response to oxidative stress, measured by TBARS, was significantly reduced in trained rats (0.4±0.1 vs. 0.7±0.1 nmol/mg protein).
Conclusions:
- Exercise training in aged rats leads to a lower resting heart rate and altered metabolic profiles (increased insulin/glucose ratio).
- Exercise training enhances myocardial protection against oxidative stress in aged rats.
- These findings suggest that regular exercise can confer significant cardiovascular benefits and improve resilience to oxidative damage in aging individuals.