Pathophysiology
Clinical meaning
Falls in older adults result from complex interactions between intrinsic factors (age-related physiological decline) and extrinsic factors (environmental hazards). Age-related changes include decreased proprioception (reduced joint position sense from mechanoreceptor degeneration), impaired vestibular function (otoconia degeneration reducing balance input), decreased visual acuity and depth perception, sarcopenia (muscle mass loss of 3-8% per decade after age 30), and slowed neuromuscular reaction time. Orthostatic hypotension (failure of baroreceptor-mediated vasoconstriction during position change) affects 30% of adults over 70. Gait changes include shortened stride length, wider base, reduced arm swing, and increased postural sway. Falls are the leading cause of injury-related death in adults >65, with hip fracture carrying 20-30% one-year mortality. Each fall increases the fear of falling, leading to activity restriction, deconditioning, and increased subsequent fall risk.