Elderly women regulate brain blood flow better than men do

Area of Science:

• Neuroscience
• Gerontology
• Cardiovascular Physiology

Background:

• Orthostatic intolerance and falls present sex-based differences and vary with age.
• The role of cerebral autoregulation in these age- and sex-related changes is not fully understood.

Purpose of the Study:

• To investigate sex-based differences in cerebral autoregulation among elderly individuals.
• To determine if cerebral autoregulation is more effective in elderly females than males.

Main Methods:

• Utilized transcranial Doppler ultrasound to assess cerebral autoregulation in 544 participants (aged >70 years).
• Evaluated CO2 reactivity, transfer function gain, phase, and coherence during quiet sitting.
• Measured autoregulatory index during sit-to-stand tests.

Main Results:

• Males demonstrated significantly lower CO2 reactivity and autoregulatory indices compared to females.
• Males exhibited higher transfer function gain and lower phase in the autoregulatory band, indicating less effective cerebral autoregulation.
• Despite being less effective, male autoregulation remained within the normal range.

Conclusions:

• Elderly females possess more effective cerebral autoregulation than males.
• Better cerebral autoregulation in females may contribute to maintaining cerebral flow velocities during postural changes.
• These findings may help explain higher rates of orthostatic hypotension-related hospitalizations in elderly men.