Walking speed and physiological responses of the elderly in smoke-filled stairwells an experimental study

Global aging necessitates understanding elderly evacuation in smoke-filled environments. This study investigated the walking speed, physiological responses, and behavioral adaptations of 40 elderly participants descending a stairwell under controlled smoke conditions. Results revealed a non-linear decrease in walking speed, identifying a critical mobility threshold at an extinction coefficient of 1.5-1.6 m^-1, where speed dropped by approximately 50%. Physiological monitoring showed that heart rate changes plateaued under dense smoke, suggesting self-regulated exertion. Crucially, participants shifted from visual to tactile navigation, with handrail reliance increasing to 85% as a compensatory strategy. Visual acuity emerged as the strongest predictor of performance. These findings define a "functional breaking point" for vertical evacuation in aging populations, providing essential empirical parameters for refining age-inclusive building codes and evacuation models.