Aerobic Exercise Training And The ∆VO2/∆WR Relationship In Women With Systemic Lupus Erythematosus

Abstract

Systemic lupus erythematosus (SLE) is an autoimmune disease that causes chronic inflammation in numerous organ systems, resulting in reduced quality of life. A common clinical feature of this disease is severe fatigue, which may be partly related to physical deconditioning and diminished cardiorespiratory fitness. Changes in oxygen uptake (∆VO2) and work rate (∆WR) relationship during incremental exercise (i.e., ∆VO2/∆WR slope) can provide insight into the efficiency of the cardiorespiratory system’s ability to respond to changing work requirements. The ∆VO2/∆WR slope has not been examined in patients with SLE, and the effect of exercise training on this population’s ∆VO2/∆WR slope has not yet been investigated. PURPOSE: To examine changes in the ∆VO2/∆WR slope following the completion of a 12-week aerobic exercise training program in patients with SLE. METHODS: Fifteen women with mild SLE disease activity underwent a 12-week exercise training program comprised of three 30-minute vigorous-intensity (70-80% of heart rate reserve) treadmill walking sessions each week. Prior and subsequent to the exercise program, patients performed an incremental treadmill cardiopulmonary exercise test (CPET). Plateaus at the start and end of the ∆VO2/∆WR data were excluded to obtain an accurate representation of the slopes. A paired t-test evaluated pre- and post- ∆VO2/∆WR slopes, and Pearson’s correlations were used to observe significant relationships with other CPET outcomes. RESULTS: A significant difference between ∆VO2/∆WR slope before and after training was not observed, even though 12 of the patients (80%) had slight increases in their slopes following exercise training (Pre: 5.02 ± 0.57; Post: 5.43 ± 0.69; p = 0.09). Correlations between the change in the ∆VO2/∆WR slope and the change (post-pre) in the following performance variables were observed: ∆ peak VO2 (r = 0.70, p < 0.01), ∆ peak VCO2 (r = 0.78, p < 0.01), ∆ peak ventilation (r = 0.56, p = 0.03) and ∆ peak heart rate (r = 0.64, p = 0.01). CONCLUSIONS: In these women with SLE, a majority saw a slight increase in their ∆VO2/∆WR slopes. A greater change in the ∆VO2/∆WR slopes was related to a greater magnitude of change in several peak CPET variables. This may suggest improvements in cardiorespiratory system efficiency following vigorous exercise training in women with SLE.