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

 PEM frequency and severity.

The last 5 items from question 6Post-exertional malaise% (n)
Next day soreness or fatigue after non-strenuous, everyday activities.
Mentally tired after the slightest effort.
Physically drained or sick after mild activity.
Dead, heavy feeling after starting to exercise.
Minimum exercise makes you physically tired.
Frequency
    None of the time
    A little of the time2.1 (20)
    About half the time10.2 (96)
    Most of the time33.5 (314)
    All of the time54.1 (508)
Severity
    Symptom not present
    Mild1.8 (17)
    Moderate15.3 (143)
    Severe44.3 (413)
    Very severe38.4 (358)