Related Experiment Videos
Cardiovascular responses during one- and two-legged exercise in middle-aged men
G Magnusson1, L Kaijser, B Isberg
1Department of Physiology and Pharmacology, Karolinska Institute, Stockholm, Sweden.
Acta Physiologica Scandinavica
|April 1, 1994
Summary
Physically active middle-aged men maintain high leg blood flow during exercise. This is achieved with increased blood pressure and sympathetic activity, similar to younger individuals.
Area of Science:
- Exercise Physiology
- Cardiovascular Physiology
- Skeletal Muscle Metabolism
Background:
- Middle-aged individuals may experience age-related declines in cardiovascular function and muscle mass.
- Regular physical activity is known to mitigate some of these age-related changes.
- Understanding skeletal muscle perfusion in active older adults is crucial for assessing exercise capacity.
Purpose of the Study:
- To investigate skeletal muscle blood flow and oxygen uptake during dynamic knee extension in healthy, physically active middle-aged men.
- To compare physiological responses between one-legged and two-legged exercise in this population.
- To assess if these men can maintain high muscle perfusion comparable to younger individuals.
Main Methods:
- Eight healthy men (44-69 years) performed incremental dynamic knee extension (one- and two-legged) to exhaustion.
- Measurements included leg blood flow, cardiac output, oxygen uptake, mean arterial pressure, and plasma concentrations of lactate, ammonia, and noradrenaline.
- Calculations of peak perfusion and limb oxygen uptake were performed.
Main Results:
- Leg blood flow increased linearly with work rate, peaking at 5.1 L/min.
- Peak quadriceps femoris perfusion reached 2.3 L/kg/min, and maximal leg oxygen uptake was 0.72 L/min.
- Two-legged exercise resulted in higher cardiac output and femoral plasma lactate, ammonia, and noradrenaline concentrations compared to one-legged exercise at maximal load.
- Mean arterial pressure increased significantly during maximal exercise.
Conclusions:
- Physically active middle-aged men can achieve high skeletal muscle perfusion, comparable to young males, with well-maintained muscle mass.
- This high perfusion is supported by elevated mean arterial pressure and increased sympathetic activity (indicated by noradrenaline).
- The findings suggest preserved cardiovascular and metabolic adaptations to exercise in active older adults.