To move or not to move: the paradoxical effect of physical exercise in axial spondyloarthritis

Key Points

1. Exercise of all types remains safe and effective as a component of management for people with axial spondyloarthritis in the short-term (symptom reduction) and long-term (general health maintenance).
2. Exercise or activity should meet minimum physical activity guidelines, be directed by personal preference, and cover components of strengthening, cardiovascular fitness and flexibility.

BACKGROUND & OBJECTIVE

Axial spondyloarthritis (AxSpA) is an autoinflammatory disorder primarily presenting with inflammatory type chronic back pain but also with high proportions of insertional tendon symptoms in the periphery. AxSpA is a disease of the entheses causing inflammatory reactions at the point where ligaments (spine and sacroiliac joints) and tendons attach to bone (1). If left untreated these enthesis locations can ossify, leading to fusion in the spine and SIJs and bony encroachment in the peripheral tendons. Several factors increase the risk of these bony changes – disease duration, being male, HLA-B27 positivity, and smoking (2).

Exercise increases load, stress and possibly the inflammatory process at these entheses, but AxSpA symptoms are often better with activity and exercise is important to maintain many general health benefits in this disease. This leads to a paradox – exercise being beneficial but also potentially detrimental. This paper aimed to explore the effect of exercise in AxSpA.

Axial spondyloarthritis often presents with high proportions of insertional tendon symptoms in the periphery.

Our best approach is to be guided by the individual's preferences, ability and symptom reactions to exercise.

METHODS

This was a review article which pulled together various studies looking at the implications of inflammation at the enthesis, genetic factors, osteoimmunological factors and pathways that would lead to these bony changes. This combination lays the framework for why people with AxSpA can go on to form new bone as a characteristic of the disease.

The reviewers also looked at mouse studies where the effect of mechanical stress was assessed for its impact on new bone formation when the mice were given arthritis. The mice that were not loaded did not develop as much inflammation and the arthritis was far slower to manifest.

RESULTS

The authors discussed the theoretical possibility that loading accelerates the formation of new bone in people with AxSpA, and the creation of the proposed paradox. This is in contradiction to many studies showing activity and exercise are highly beneficial to outcomes in AxSpA. There are also a number of confounding factors. For example, men tend to get more new bone formation and also tend to have higher load jobs (e.g. construction), so would the exercise performed as “therapy” actually make any difference overall?

Exercise also reduces systemic inflammation and therefore the outcomes in AxSpA. Does this mean that in a risk vs reward scenario, it would still be better to use high load activities to address bone density, cardiovascular fitness, function and so on? It is also not possible to comment at this time on the effect of NSAIDs and anti-TNF medications on mechanical load on the entheseal organ, and almost all AxSpA patients will be treated with one or both of these.

LIMITATIONS

• The most obvious limitation of this review is that a lot of the studies are pre-clinical (in mice), and this significantly reduces the accuracy of translating this to human biology.
• AxSpA is also a highly heterogenous condition – even within the narrow measure of new bone formation significant variations exist in the likelihood of developing new bone.
• Before significantly changing clinical practice, we need to understand not only if this does indeed translate to human pathobiology, but also if the increased development of new bone is in fact detrimental (i.e. whether patients without new bone formation have the same disease burden as those with it).

CLINICAL IMPLICATIONS

While this paper suggests the possibility that loading entheseal organs could lead to increased new bone formation, our current understanding of AxSpA is that exercise is a vital component of management. In the short-term, symptoms are improved with activity, and keeping people active or reassuring them that it’s ok to be active is often received gratefully from those who subscribe to the medical models of exercise causing joint damage or wear and tear.

In the medium and long-term, functional and general health outcomes are also impacted by activity levels and exercise. Osteoporosis and cardiovascular disease risks are increased with a diagnosis of AxSpA due to the effects of systemic inflammation. Loading the body structures maintains their quality and also aids in maintaining appropriate levels of body fat.

Exercise or activity in inflammatory arthropathies (e.g. AxSpA and rheumatoid arthritis) appears to be effective across the spectrum of intensities, showing that adherence and enjoyment are more important than specificity in this cohort (3).

Given the current evidence base and the limitations of the research used to create this paper, we should not change our clinical practice at this time but remain wary of future publications. Our best approach is to be guided by the individuals’ preferences, ability and symptom reactions to exercise. We should advise AxSpA patients to maintain the minimum physical activity guidelines including components of strengthening, cardiovascular fitness and flexibility, and assist them with achieving this as appropriate on an individual basis. Educating and reassuring patients that activity and exercise is safe and beneficial regardless of their specific choice remains an evidence-based approach.

+STUDY REFERENCE

Perrotta F, Lories R and Lubrano E (2021) To move or not to move: the paradoxical effect of physical exercise in axial spondyloarthritis. RMD Open, 7(1), p.e001480.

SUPPORTING REFERENCE

1. Wendling, D., Claudepierre, P. and Prati, C., 2013. Early diagnosis and management are crucial in spondyloarthritis. Joint Bone Spine, 80(6), pp.582-585.
2. López-Medina, C., Ramiro, S., van der Heijde, D., Sieper, J., Dougados, M. and Molto, A., 2021. Characteristics and burden of disease in patients with radiographic and non-radiographic axial Spondyloarthritis: a comparison by systematic literature review and meta-analysis.
3. Millner, J., Barron, J., Beinke, K., Butterworth, R., Chasle, B., Dutton, L., Lewington, M., Lim, E., Morley, T., O’Reilly, J., Pickering, K., Winzenberg, T. and Zochling, J., 2016. Exercise for ankylosing spondylitis: An evidence-based consensus statement.