E-14R Free Communication/Poster Rehabilitation and Chronic Disease
Debilitating fatigue is a cardinal symptom of both SLE and FM. Severely diminished aerobic capacity has been associated with debilitating fatigue in SLE.
This study aimed to determine if aerobic capacity differs among women with mild SLE and FM.
Maximal treadmill testing with open circuit spirometry was used to measure ventilatory threshold (Tvent) and peak oxygen consumption (VO2peak) in 45 physically inactive women similar in weight and body mass index: 18 with mild (SLAM <9) SLE, 11 with FM, and 16 healthy controls. ANCOVA with age (SLE=34.8±8.8 yrs; FM=43.1±7.4 yrs; Control=37.0±6.3 yrs) as the covariate was used to identify significant (p ≤ .05) differences in Tvent and VO2peak.
Tvent was significantly (p < .01) lower in the women with SLE (11.3±0.8 ml/kg/min) than in controls (16.6 ± 0.9 ml/kg/min). In the women with FM, Tvent(13.5± 1.1 ml/kg/min) differed neither from those with SLE nor controls. All of the women met criteria indicating that VO2 approached a maximal level at volitional exhaustion. VO2peak was significantly lower in the women with mild SLE (19.2±4.4 ml/kg/min) than in the women with FM (23.6±4.9 ml/kg/min; p < .05) and controls (27.4±4.7 ml/kg/min; p < .01). A significant difference in VO2peak was not observed for those with FM compared to controls. Tvent and VO2peak were similar to the lower and upper limits of energy requirements (3–5 METS = 10.5 – 17.5 ml/kg/min) for instrumental activities of daily living (iADL) in the women with SLE. Tvent was similar to the upper limit of the iADL range in controls and VO2peak exceeded the upper limit of the iADL range in both women with FM (p < .05) and controls (p < .01). 14 of the 18 women with SLE (74%) had functional aerobic impairment (FAI) whereas only four of the 11 women with FM (36%) had FAI.
Results of this study suggest that FAI limits the ability to carry out iADL in women with even mild SLE as well as in a smaller subset of women with FM.