The aim of this study is to evaluate the effect of a 12-week individualized exercise program in subjects with SLE in comparison to treatment-as-usual therapy. Several previous studies showed that exercise leads to various benefits in treating SLE, including enhanced aerobic capacity, reduced symptoms of depression and fatigue. Moreover, it has been shown that exercise is well tolerated and does not impair disease activity in SLE negatively. Here, the effects of an individual internet-based exercise therapy for 12 weeks will be evaluated.