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

 Correlation matrix of standardized PEM components.

TriggersDurationDelayPacingSymptomsFrequencySeverity
Duration0.26**
Delay0.07*0.20**
Pacing0.050.06*–0.18**
Symptoms0.34**0.20**–0.19**0.26**
Frequency0.28**0.22**–0.13**0.21**0.62**
Severity0.27**0.22**–0.15**0.25**0.63**0.71**
SF-36–0.47**–0.28**0.01–0.13**–0.40**–0.52**–0.46**

*: p < 0.05; **: p < 0.01.