Table 1.

Demographic and challenge related information of subjects included in this study.

Exercise Challenge Information	Subjects
	CFS	Controls
Mean Age	41.8	36.1
Age Range	35–48	27–45
Average workload performed during exercise challenge in watts.	1360	1664
Mean change in score of daily symptom diary (± SE) calculated for the exercise challenge.#	1.61 ± 0.65*	0.54 ± 0.31

^#A 10 symptom daily diary with a 0 to 4 scale was filled out each day for 2 weeks before and 1 week after challenge [22].

*Significant relative to control patients at P < 0.05