Aerobic Exercise Training Improves Orthostatic Tolerance in Aging Humans

Area of Science:

• Gerontology
• Cardiovascular Physiology
• Exercise Science

Background:

• Aging is associated with declines in aerobic fitness and orthostatic tolerance.
• Maintaining cardiovascular function in the elderly is crucial for preventing falls and ensuring adequate tissue perfusion.

Purpose of the Study:

• To investigate the effects of aerobic exercise on aerobic fitness and orthostatic tolerance in elderly individuals.
• To determine if exercise training compromises orthostatic tolerance in this population.

Main Methods:

• Eight healthy, sedentary older adults (average age 67) underwent a 1-year aerobic exercise program.
• Assessments included peak oxygen uptake, heart rate, carotid baroreceptor reflex sensitivity, and orthostatic tolerance via lower-body negative pressure.
• Carotid baroreceptor reflex function was evaluated using neck pressure-suction stimuli to derive maximal gain (Gmax).

Main Results:

• Aerobic exercise training significantly increased peak oxygen uptake (V˙O2peak) and peak heart rate (HRpeak).
• Resting heart rate and mean arterial pressure were reduced post-training.
• Orthostatic tolerance, measured by the cumulative stress index during lower-body negative pressure, significantly improved.
• Carotid baroreceptor reflex sensitivity (CBR-HR Gmax) increased, indicating enhanced reflex control.

Conclusions:

• Aerobic exercise training is effective in improving both aerobic fitness and orthostatic tolerance in elderly individuals.
• The enhanced orthostatic tolerance appears to be associated with an improved carotid baroreceptor reflex function.
• This suggests that exercise training can help maintain cerebral perfusion and oxygenation during orthostatic stress in older adults.