Hemodynamic responses to positional change in habitually physically active and inactive older men

Area of Science:

• Cardiovascular Physiology
• Gerontology
• Exercise Science

Background:

• Aging is associated with cardiovascular changes.
• Physical activity may mitigate age-related cardiovascular decline.
• Understanding hemodynamic responses to posture is crucial for older adults.

Purpose of the Study:

• To compare hemodynamic responses to positional changes in physically active versus inactive older men.
• To investigate the long-term effects of habitual physical activity on cardiovascular regulation in aging.
• To assess differences in heart rate, stroke volume, cardiac output, and total peripheral resistance across various body positions.

Main Methods:

• Cross-sectional study involving 22 healthy older men (mean age 70 years).
• Participants were categorized into habitually physically active (n=11) and physically inactive (n=11) groups.
• Hemodynamic variables (heart rate, stroke volume, cardiac output, total peripheral resistance) were measured in supine, sitting, standing, and 70° upright tilt positions.

Main Results:

• Physically active men demonstrated significantly lower resting heart rates and higher stroke volume indices across all positions.
• Trends suggested lower total peripheral resistance and higher cardiac indices in active men, though not statistically significant.
• Both groups responded similarly to positional changes, except for a greater decrease in stroke volume index in active men during upright tilt compared to supine.

Conclusions:

• Habitual physical activity is associated with enhanced resting cardiovascular function and improved stroke volume in older men.
• While physical activity confers benefits, older active men may experience a more pronounced reduction in stroke volume index upon assuming an upright posture.
• These findings highlight the cardiovascular advantages of exercise in older adults and suggest nuanced responses to orthostatic stress.