Myocardial adaptations to endurance exercise in aged rats

Area of Science:

• Cardiology
• Exercise Physiology
• Gerontology

Background:

• Aging is associated with declines in myocardial function and aerobic energy metabolism.
• Exercise interventions may mitigate age-related cardiac decline.

Purpose of the Study:

• To investigate the effects of endurance training on cardiac function and metabolism in aged rats.
• To compare the cardiac performance of trained aged rats with young sedentary and aged sedentary rats.

Main Methods:

• Isolated perfused working heart preparations from Sprague-Dawley rats (9-mo and 25-mo old).
• Comparison of trained 25-mo-old rats (16 weeks of running) with sedentary 9-mo-old and 25-mo-old controls.
• Assessment of hemodynamic parameters (pressures, flow), oxygen consumption, and left ventricular mitochondrial function (cytochrome c, substrate oxidation rates).

Main Results:

• Under high workload, trained aged rats exhibited higher systolic pressure than sedentary aged rats.
• Coronary flow and oxygen consumption were improved in trained aged rats compared to sedentary aged controls.
• Training increased left ventricular cytochrome c concentrations and substrate oxidation rates in aged rats, though not to levels of young controls.

Conclusions:

• Appropriate exercise training in aged animals enhances myocardial function and aerobic energy metabolism.
• Exercise can partially reverse age-related deficits in cardiac performance and metabolic capacity.
• Findings suggest exercise is a viable strategy to improve cardiovascular health in aging populations.