Anomalous Perceptual Experience During Ultra-Endurance Sport: A Systematic Review.
Wilderness & environmental medicine March 18, 2026 Elizabeth E Davidson, Sean L Davidson, Paul Glue
Anomalous perceptual experiences (APEs)—such as visual, auditory, somatic, and sensed presence phenomena—occur in ultra-endurance athletes without psychiatric illness. A systematic review of 14 studies (case reports, case series, field studies, and cross-sectional surveys) found APEs across mountaineering, ultramarathon running, solo sailing, marathon volleyball, and dogsled racing. Sleep deprivation was the most consistent contributing factor, followed by exhaustion and low-light conditions. Symptoms typically emerged after 24 hours of exertion, especially in darkness. Interpretations ranged from distressing to neutral or supportive, and no long-term psychiatric sequelae were reported. APEs appear to be transient, nonpathologic phenomena triggered by extreme stress, with implications for athlete safety and event planning.