From:  A brief, comprehensive measure of post-exertional malaise

 Triggers of PEM.

Triggers% (n)
Minimal amounts of physical and/or cognitive exertion97.3 (1,492)
Emotional stress93.2 (1,429)
Noise85.3 (1,308)
Sensory overload83.6 (1,282)
Visual overload79.7 (1,223)
Basic activities of daily living78.2 (1,199)
Heat74.4 (1,141)
Light68.8 (1,055)
Cold66.3 (1,017)
Positional changes64.5 (990)
Foods61.0 (935)
Chemicals58.0 (889)
Watching movement52.5 (806)
Mold39.4 (605)