Perceived exertion in fatiguing illness: Gulf War veterans with chronic fatigue syndrome.
OBJECTIVE
It has been reported that ratings of perceived exertion (RPE) are elevated in chronic fatigue syndrome (CFS). We have challenged this notion by examining perceived exertion in civilian females with CFS and expressing the data relative to exercise capacity (%[OV0312]O(2max)). The purpose of the present investigation was to further examine RPE during exercise in a unique population of CFS patients, Gulf veterans (GV).


METHODS
Thirty-four GV (N = 15 CFS, 42 +/- 8 yr; N = 19 healthy, 43 +/- 5 yr) performed a maximal exercise test on a cycle ergometer. After a 3-min warm-up, exercise intensity increased by 30 W every minute until exhaustion. RPE were obtained during the last 15 s of each minute using Borg's CR-10 scale.


RESULTS
With the exception of peak [OV0312]E, there were no significant differences in any peak exercise variables. Repeated measures ANOVA revealed significantly higher RPE at each power output examined (F(1,32) = 16.4, P < 0.001). Group differences in RPE remained significant when analyzed relative to peak [OV0312]O(2) (F(1,32) = 7.2, P = 0.01). Both group main effects and the interaction were eliminated when self-reported fatigue symptoms were controlled for in the analyses. Power functions for RPE as a function of relative oxygen consumption were not different between groups and were significantly greater than a linear value of 1.0 (1.6 +/- 0.3 for both groups, P < 0.02).


CONCLUSIONS
Our results show that RPE are greater in GV with CFS regardless of whether the data were expressed in terms of absolute or relative exercise intensity. However, self-reported fatigue associated with CFS eliminated the group differences. These results suggest that GV with CFS were unique compared with their civilian counterparts. Future research aimed at determining the influence of preexisting fatigue on RPE during exercise is warranted.
Cook
Dane B
DB
Center for the Study of War-Related Illnesses, VA NJ Health Care, East Orange, NJ 07018, USA. cookdb@njneuromed.org
Nagelkirk
Paul R
PR
Peckerman
Arnold
A
Poluri
Ashok
A
Lamanca
John J
JJ
Natelson
Benjamin H
BH
D000328:Adult; D016022:Case-Control Studies; D005080:Exercise Test; D015673:Fatigue Syndrome, Chronic / Q000503:physiopathology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010101:Oxygen Consumption; D010465:Perception; D018923:Persian Gulf Syndrome / Q000150:complications* / Q000503:physiopathology; D010807:Physical Endurance; D014728:Veterans