Anomalous Perceptual Experience During Ultra-Endurance Sport: A Systematic Review

Area of Science:

• Sport Science
• Psychology
• Neuroscience

Background:

• Anomalous perceptual experiences (APEs) are anecdotally reported in ultra-endurance athletes.
• These experiences occur without psychiatric illness and may stem from extreme physiological and environmental stressors.
• Existing literature is fragmented, with inconsistent terminology hindering understanding of APEs' nature, prevalence, and mechanisms.

Purpose of the Study:

• To systematically review the literature on APEs during ultra-endurance sport.
• To characterize the phenomenology, contextual features, and contributing factors of APEs.
• To provide a foundation for consistent terminology and categorization frameworks.

Main Methods:

• Systematic literature search of Medline, Embase, and PsycINFO (August 2025).
• Inclusion criteria: studies reporting APEs in adults participating in ultra-endurance sports (≥6 hours).
• Data extracted for narrative synthesis following PRISMA guidelines; included studies appraised for quality.

Main Results:

• Fourteen studies met inclusion criteria across diverse sports (mountaineering, ultramarathon running, solo sailing, etc.).
• APEs were commonly visual, but also auditory, somatic, and included "sensed presence" phenomena.
• Sleep deprivation, exhaustion, and low-light conditions were key factors, with symptoms emerging after ≥24 hours of exertion, especially in darkness.

Conclusions:

• APEs in ultra-endurance athletes are transient, non-pathologic phenomena.
• These experiences are triggered by extreme stressors like sleep deprivation and exhaustion.
• Findings have implications for athlete safety, event planning, and future research, highlighting the need for consistent terminology.