Change of BDI score after 12-weeks compared to baseline to measure the severity of depression. The BDI questionnaire consists of 21 sets of statements. Each set consists of 4 statements which are ranked in terms of severity from 0 to 3. The sum of the item scores (range 0-63) indicates the severity of depression. The standardized scale is: 0-8: no depression. 9-13: minimal depression. 14-19: mild depression. 20-28: moderate depression. 29-63: severe depression.

The Safety of Estrogens in Lupus Erythematosus National Assessment (SELENA) - Systemic Lupus Erythematosus Disease Activity Index (SLEDAI) (SELENA-SLEDAI) will be used to measure the disease activity. The index consist of 24 items including clinical and laboratory variables to measure disease activity within the previous 10 days. The maximum score is 105. SLEDAI scores >3 indicate a mild or moderate flare, SLEDAI ≥12 indicate a severe flare.

Change of DAS 28 score after 12-weeks compared to baseline. The DAS 28 score indicates rheumatoid arthritis disease activity and treatment response. The score composes of 4 measures including the number of swollen/tender joints, C reactive protein and patients health assessment. A total score is calculated using the DAS 28 formula. Values range from 2.0 to 10, whereas higher values indicate higher disease activity.

The WAI self-assessment questionnaire will be used to assess the workability of the patients. The questionnaire covers six dimensions including current workability, as well as past 2 year estimation among others. The answers have different scores, which are summed to a total score, leading to four categories. 7-27 points indicate bad, 28-36 points moderate, 37-43 good, and 44-49 points very good workability.

The concentration of cfDNA (ng/ml) will be measured during and after acute exercise at baseline and after 12-weeks exercise intervention using quantitative PCR. Compared to healthy subjects SLE patients show higher cfDNA plasma levels.

Change of score on RCLASI after 12-weeks compared to baseline. The RCLASI scoring system includes the RCLASI Activity Score to measure the activity of skin lesions, and the RCLASE Damage Score to measure the damage of skin lesions in patients with discoid lupus erythematosus and cutaneous lupus erythematosus. The score is used as a follow-up parameter for the Lupus activity of the skin. It was also shown that RCLASI correlates well with the physicians and patients global assessment of disease activity.

The relative amount of EV subpopulations will be analyzed before and after acute exercise, as well as after 12-weeks of exercise intervention using bead isolation and or size exclusion chromatography followed by protein marker characterization.

Change of antinuclear antibodies (ANA) titer after 12-weeks of exercise intervention compared to baseline (standard value ≤1:80).

Change of VT after 12-weeks compared to baseline.

Change of muscle mass after 12-weeks compared to baseline. Muscle mass will be measured in absolute mass [kg] including internal organs using bioelectrical impedance analysis (InBody 3.0 Body composition analyzer).

Change of CST after 12-weeks compared to baseline.