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PURPOSE: To evaluate the aerobic power (as maximum volume of oxygen consumed [VO [sub 2] max!) of women with chronic fatigue syndrome (CFS). PATIENTS AND METHODS: Twenty-one women with CFS and 22 sedentary healthy controls (CON) were studied at the CFS Cooperative Research Center Exercise Laboratory at the VA Medical Center, East Orange, New Jersey. Performance was measured on an incremental treadmill protocol walking to exhaustion. Expired gases were analyzed by a metabolic system, heart rate was recorded continuously, and ratings of perceived exertion (RPE) were taken at each workload. The groups were divided into those who achieved VO [sub 2] max (CFS-MAX and CON-MAX) and those who stopped at a submaximal level (CFS-NOMAX and CON-NOMAX) by using standard criteria. RESULTS: Seventeen CON and 10 CFS subjects achieved VO [sub 2] max. The VO [sub 2] max (mL/kg/min) of the CFS-MAX (28.1 [+ or -] 5.1) was lower than that of the CON-MAX (32.1 [+ or -] 4.3, P = 0.05). The CFS-MAX achieved 98 [+ or -] 11% of predicted VO [sub 2] max. The CFS group had a higher RPE at the same absolute workloads as controls (P < 0.01) but not the same relative workloads. CONCLUSION: Compared with normal controls, women with CFS have an aerobic power indicating a low normal fitness level with no indication of cardiopulmonary abnormality. Our CFS group could withstand a maximal treadmill exercise test without a major exacerbation in either fatigue or other symptoms of their illness. Am J Med. 1996;100:634--640.

A large overlap exists between the diagnosis of chronic fatigue syndrome (CFS) and the unexplained symptoms reported by many Gulf War veterans (GV). Previous investigations have reported reduced aerobic capacity in civilians with CFS. The present investigation examined metabolic responses to maximal exercise in GVs with CFS compared with healthy GVs. Cardiorespiratory and metabolic responses were recorded during a maximal exercise test on a cycle ergometer. The groups were not different in any demographic category (p > 0.05) or self-reported physical activity (p > 0.05). No differences were observed between groups for maximal oxygen uptake (28.9 +/- 6.7 mL/kg/min for CFS vs. 30.8 +/- 7.1 mL/kg/min for controls; p = 0.39), heart rate (155.8 +/- 16.1 bpm for CFS vs. 163.3 +/- 14.9 bpm for controls; p = 0.17), exercise time (9.6 +/- 1.5 minutes for CFS vs. 10.2 +/- 1.4 minutes for controls; p = 0.26), or workload achieved (208 +/- 36.7 W for CFS vs. 224 +/- 42.9 W for controls; p = 0.25). Likewise, no differences were observed at submaximal intensities (p > 0.05). Compared with healthy controls, GVs who report multiple medically unexplained symptoms and meet criteria for CFS do not show a decreased exercise capacity. Thus, it does not appear that the pathology of the GVs with CFS includes a deficiency with mobilizing the cardiopulmonary system for strenuous physical effort.

LaMANCA J. J. and E. M. HAYMES. Effects of iron repletion on VO2mx, endurance, and blood lactate in women. Med. Sci. Sports Exerc., Vol. 25, No. 12, pp. 1386–1392, 1993. To determine the effects of an 8-wk dietary iron supplementation (100 mg.d-1) on low plasma ferritin concentration (<20 ng.ml-1) and endurance, 20 active women (19–35 yr) were studied while performing a O2maxtest and an endurance test (80 O2max) on a cycle ergometer. Subjects were randomly placed in an iron supplement (IG) or a placebo group (PG) using a double-blind method. After treatment in the IG, ferritin levels were higher (22.5 ± 3.4 vs 14.3 ± 2.2 ng.ml-1; P< 0.05), Hb increased (12.8 ± 0.4 to 14.1 ± 0.2 g.dl-1; P< 0.05), and TIBC decreased (366.2 ± 24.8 to 293.8 ± 14.0 μg.dl-1; P< 0.05). Also after treatment the IG's O2maxwas significantly greater (P<0.05) than the PG value and their postendurance blood lactate decreased (5.03 ± 0.44 to 3.85 ± 0.6 mM.1-1; P< 0.05). Endurance time to exhaustion increased 38 (37.28 ± 5.03 to 51.4 ± 7.45 min) following iron treatment; however, this change was not statistically significant. The results suggest that this level of iron supplementation can reverse mild anemia, increase O2max, and reduce blood lactate concentration after submaximal exercise.