Aging attenuates the vestibulorespiratory reflex in humans

• Published in: The Journal of physiology Vol. 548; no. 3; pp. 955 - 961
• Main Authors: Kuipers, Nathan T, Sauder, Charity L, Ray, Chester A
• Format: Journal Article
• Language: English
• Published: England The Physiological Society 01-05-2003; Blackwell Science Inc
• Subjects: Adult; Aged; Aging - physiology; Biomechanical Phenomena; Female; Head; Humans; Male; Original; Posture; Reference Values; Reflex - physiology; Respiratory Mechanics; Rotation; Semicircular Canals - physiology; Tidal Volume; Vestibule, Labyrinth - physiology
• ISSN: 0022-3751; 1469-7793
• DOI: 10.1113/jphysiol.2002.033357

Activation of the vestibular system changes ventilation in humans. The purpose of the present study was to investigate whether
aging alters the vestibulorespiratory reflex in humans. Because aging attenuates the vestibulosympathetic reflex, it was hypothesized
that aging would attenuate the vestibulorespiratory reflex. Changes in ventilation during engagement of the semicircular canals
and/or the otolith organs were measured in fourteen young (26 ± 1 years) and twelve older subjects (66 ± 1 years). In young
subjects, natural engagement of the semicircular canals and the otolith organs by head rotation increased breathing frequency
during dynamic upright pitch at 0.25 Hz (15 cycles min −1 ) and 0.5 Hz (30 cycles min −1 ) (Δ2 ± 1 and Δ4 ± 1 breaths min −1 , respectively; P < 0.05) and during dynamic upright roll (Δ2 ± 1 and Δ4 ± 1, respectively; P < 0.05). In older subjects, the only significant changes in breathing frequency occurred during dynamic pitch and roll at
0.5 Hz (Δ2 ± 1 and Δ2 ± 1 for pitch and roll, respectively). Stimulation of the horizontal semicircular canals by yaw rotation
increased minute ventilation in young but not older subjects. Selective engagement of the otolith organs during static head-down
rotation did not alter breathing frequency in either the young or older subjects. The results of this study indicate that
the vestibulorespiratory reflex is attenuated in older humans, with greater vestibular stimulation needed to activate the
reflex.