Background/Purpose: Ankylosing Spondylitis (AS) is a systemic inflammatory disease that causes deterioration of physical capacity. Although exercises remain essential in the treatment, the literature lacks research on the mechanisms by which exercises lead to clinical improvements in patients with AS. The purpose of this study was to evaluate the effects of aerobic exercise on functional capacity, mobility, disease activity, aerobic capacity, quality of life and cytokine levels (TNF-α, IL-1β, IL-6 and IL-10) in patients with AS.

Methods: Seventy patients with a diagnosis of AS, according to New York modified criteria and with stable drug treatment, were included. The patients were randomly allocated in two groups. The intervention group (IG) underwent 50 minutes of walking in the individual anaerobic threshold associated with stretching exercises 3 times a week for 12 weeks. The control group (CG) performed stretching exercises 3 times a week for 12 weeks. The outcome measurements were: functional capacity measured using BASFI (The Bath Ankylosing Spondylitis Functional Index), HAQ-S (Health Assessment Questionnaire for spondyloarthritis) and the 6-minute walking test (6MWT); mobility measured using BASMI (The Bath Ankylosing Spondylitis Metrologyl Index); disease activity by BASDAI (The Bath Ankylosing Spondylitis Disease Activity Index) and ASDAS (Ankylosing Spondylitis Disease Activity Score). Aerobic capacity was evaluated using an incremental cardiopulmonary exercise testing protocol by treadmill. TNF-α, IL-1ß, IL-6 and IL-10 levels were measured using ELISA method. The evaluations were done by a blinded assessor immediately before the randomization, 6 weeks, and 12 weeks after the beginning of the exercise programs. It was used intention-to-treat analysis.

Results: Thirty-five patients were randomized to IG and 35 to CG. Two patients from CG and one patient from IG withdrew because of time availability. At baseline, the groups were homogeneous regarding all clinical and demographic characteristics. There were significant improvements in BASFI, HAQ-S, BASDAI and ASDAS scores in both groups (p < 0.05), but there was no difference between groups. There was no significant improvement of mobility and quality of life in both groups. The IG showed significant improvement in 6MWT compared to the control group (p < 0.001). There was significant increase in VO₂ peak and anaerobic threshold (AT) in IG after treatment. In CG, VO₂ peak and AT did not change after 12 weeks. There was significant difference between groups in absolute values of  VO₂ peak (p=0.049) and O₂pulse (p=0.039) at 12 weeks. TNF-α, IL-1ß, IL-6 levels did not change over time in both groups. IL-10 levels decreased in both groups after 12 weeks compared to baseline (p< 0.001), but there was no difference between groups.

Conclusion: Aerobic training and stretching exercises had beneficial effects on functional capacity and disease activity. Aerobic training, in addition to stretching exercises, increased walking distance and cardiopulmonary capacity in patients with AS. Aerobic exercise did not affect cytokine levels. More studies are need to understand the mechanisms by which exercises have a therapeutic role in AS.

ACR Meeting Abstracts - https://acrabstracts.org/abstract/benefits-of-aerobic-training-in-patients-with-ankylosing-spondylitis-are-not-coupled-by-effects-on-cytokines-a-randomized-controlled-trial/