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Effects of aerobic and muscle strengthening exercise in adults with rheumatoid arthritis: a narrative review summarising a chapter in Physical activity in the prevention and treatment of disease (FYSS 2016)
  1. E Swärdh1,2,
  2. N Brodin1,3
  1. 1Division of Physiotherapy, Department of Neurobiology, Care Sciences and Society, Karolinska Institutet, Huddinge, Sweden
  2. 2Department of Physiotherapy, Karolinska University Hospital, Huddinge, Sweden
  3. 3Division of Physiotherapy, Department of Orthopaedics, Danderyd Hospital, Stockholm, Sweden
  1. Correspondence to Dr Nina Brodin, Division of Physiotherapy, Department of Neurobiology, Care Sciences and Society, Karolinska Institutet, 23100, Huddinge 14183, Sweden; nina.brodin{at}ki.se

Abstract

Background Besides pharmacological treatment, regular exercise is one of the cornerstones of care in rheumatoid arthritis (RA). In many of the earlier studies of exercise in RA, the intensity of the exercise did not reach the current recommendations or is not described in satisfactory detail. This narrative review is based on randomised controlled trials with a detailed description of the exercise type, frequency, duration and intensity.

Results There is moderate-quality evidence that short-term land-based aerobic exercise of moderate to high intensity augments oxygen uptake but does not improve muscle strength. Short-term water-based aerobic exercise of moderate to high intensity augments oxygen uptake; short term land-based aerobic and muscle strengthening exercise of moderate to high intensity augments oxygen uptake and muscle strength. Long-term land-based aerobic and muscle strengthening exercise of moderate to high intensity reduces activity limitations and improves both oxygen uptake and muscle strength.

Conclusions Clinicians should recommend that patients with RA participate in various types of exercise.

  • Aerobic fitness
  • Exercise
  • Physical activity
  • Rehabilitation

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Introduction

Rheumatoid arthritis (RA) is a chronic, autoimmune, inflammatory, systemic disease mainly affecting the joints. The estimated prevalence of RA in Europe and the USA is 0.5–1% of the general adult population,1 and in Sweden it is 0.5–0.7%.2 There is a predominance in women; the female/male gender ratio is reported to be 3:1.1 ,3 Disease onset can be at any age, but most common is between the ages of 45 and 65. The incidence rate is approximately 25–50 new cases per 100 000 residents each year.4 The fundamental cause of RA is largely unknown, but the processes leading to the disease include autoimmune reactions based on a combination of genetic susceptibility and environmental factors.5 Also of particular interest are lifestyle factors, such as smoking, which has a negative effect on the incidence as well as the prognosis and response to medication, and also physical activity, which leads to milder symptoms at disease onset.6

RA includes symmetric polyarthritis and often exhibits a fluctuating course characterised by chronic inflammation of the synovial joint-lining membranes (synovitis), tendon sheaths (tendovaginitis) and bursae (bursitis) and by bone and cartilage destruction.5 Weakening of the bones (osteopenia and osteoporosis) with an ensuing increased risk of osteoporosis-related fractures is a consequence of the actual disease process itself in combination with physical inactivity and, if applicable, cortisone treatment.7–9

The onset of the disease can be acute or it may appear more progressive over a long time. The cardinal symptom of RA is pain which, although varying in intensity, localisation and quality, is considered to be chronic. Swollen joints, stiffness, tenderness, disease-induced fatigue and stress reactions are common.10–12 A large proportion of individuals with RA exhibit reduced joint flexibility, muscle function and aerobic fitness early in the course of the disease despite adequate medical treatment.13 Pain associated with RA is predominantly of a nociceptive character and associated with the inflammatory tissue process, but it can also be neurogenic or widespread. The reduced range of joint motion accompanies increased joint fluid, thickened joint capsules and changes in load conditions as a consequence of cartilage and bone destruction. The reduced muscle function can be explained partly by muscle inflammation and changes in the joint. This can lead to elongated tendons, ligaments and joint capsules and, as a result, joint instability, reduced muscle mass and strength. The fatigue induced by the disease is thought to be related mainly to pain, but also cerebral inflammation and physical inactivity.5

Apart from joint problems, general symptoms of inflammation also exist in, for example, the pericardium and pleura, and the blood vessels in skin and inner organs. Physical activity and exercise is often limited in individuals with RA, which, together with fatigue and sometimes heart and lung engagement, leads to deterioration of fitness levels. Individuals with RA are at increased risk of cardiovascular disease and premature death compared with the general population.7 ,14 Inactive individuals with RA are at increased risk of cardiovascular disease compared with more active individuals with RA.15 ,16 RA is traditionally treated with drugs, surgery and various forms of non-pharmacological treatment including exercise17 and rehabilitation. Significant advances in medical treatment options have been made in recent years, with the aim to reduce disease activity, stop or delay the development of structural damage, and induce remission. However, the drugs do not induce remission in all individuals.18 ,19 Thus, modern medical treatment has contributed to significantly improving the prognosis and disease progression in individuals with RA.18 ,19 Along with treatment with drugs, non-pharmacological treatment such as exercise should be offered to all patients with RA, as such treatments have the potential to improve body functions and reduce activity limitations independent of medical treatment.

Benefits of exercise prescription

Exercise can be used to treat the consequences of RA, since primary prevention of the disease is not possible with such activities. Individuals with RA may benefit from applying and incorporating the physical activity guidelines for general health and fitness20 as a natural part of daily life, in order to improve and maintain their physical and mental health as well as to reduce the increased risks of comorbidities. Improving cardiorespiratory fitness and/or muscle strength without deterioration of the disease can be achieved through exercise by individuals with RA who have low to moderate disease activity with no severe joint destruction.21–37 It seems that the functional mechanisms of exercise in medically well-controlled RA are the same as in the general population. Exercise leads to reduced levels of proinflammatory cytokines, such as tumour necrosis factor, in healthy individuals and in individuals with heart failure and type 2 diabetes.38 Exercise can also have a counter effect on the so-called rheumatoid cachexia by increasing the proportion of fat-free body mass.38 A few studies have shown positive effects of exercise on established cardiovascular risk and risk factors, but more studies are needed.28 ,39

Unfortunately, inactivity remains common among individuals with RA, despite the broad spectrum of health benefits from exercise. Factors shown to have an impact on maintaining physical activity in RA are self-efficacy, social support and outcome expectations related to physical activity.40 As RA is a life-long disease, it is important to ensure that the exercise is carried out as independently from healthcare professionals as possible and also to support these factors in order to support maintenance.

Suitable forms of exercise for individuals with RA are cycling, cross-country skiing, walking, Nordic walking, gymnastics, dancing and muscle strengthening physical activity with machines or rubber expanders.41 Exercise can also be performed in water, which reduces the body's weight while at the same time providing a soft and even resistance. According to clinical experience, the intensity or load of exercise should be slowly introduced and increased gradually during periods of at least 2–3 weeks in order to reduce the risk of aggravating symptoms. It is also important to adjust exercise to fluctuations of the disease.

Adverse events and contraindications to exercise

Individuals with RA sometimes experience increased levels of pain as a result of exercise. This temporary increase in pain is seen as soreness from subjecting muscles and joints to an increased load. The pain is usually transient, harmless and does not normally hinder continued activity. An often used method among health professionals is the so-called 24 h rule, where intensity or load is temporarily reduced if increased pain persists for more than 24 h after exercise. Wrist orthosis or specially adapted shoes or insoles can be introduced to facilitate exercise if pain is present.

There are no absolute contraindications to exercise in individuals with RA, other than those for the general population. Also, relative contraindications that apply to the general population apply to individuals with RA, and healthcare professionals should pay particular attention to those described below. Pericarditis, heart failure, pleuritis, pulmonary fibrosis, vasculitis and kidney enlargement can all be associated with RA. Individuals with these complaints require individually tailored exercise supervised by healthcare professionals. In osteoporosis, which is relatively common in RA, exercise is an important part of the treatment to stimulate and strengthen the skeleton. However, not to be forgotten is the increased risk of fractures, thus particular attention should be paid to preventing falls. Individuals with destruction of large joints should be advised that the use of high-intensity exercise should be weighed against the risk of more rapid development of joint destruction. Some caution is recommended for extreme exercise during treatment with cortisone, a catabolic steroid. The strength and stability of muscles and tendons is reduced following cortisone treatment, which might lead to ruptures if the physical load is heavy. However, during long-term low-dose oral cortisone treatment, the benefits of exercise balance the risks. There are no other restrictions as to how intensive exercise should be performed in relation to ongoing antirheumatic treatment.

Exercise is recommended to patients with RA both in early disease42 and in general.17 Further, to gain effects on cardiorespiratory fitness and muscle strength, it is important that sufficient frequency, duration and intensity is reached. In a Cochrane review from 2009 by Hurkmans et al,43 it was concluded that patients with RA should be recommended combined aerobic and muscle strengthening exercise as routine practice. The review included eight studies with high methodological quality from 1985 to 2003. Since then, there have been developments in our knowledge of the relation between cardiorespiratory fitness and risk of cardiovascular disease in RA,15 ,16 and an update of research on the effects of exercise is timely.

We reviewed the evidence available up to September 2015 on the effects of aerobic and muscle strengthening exercise in RA on cardiorespiratory fitness, muscle strength, activity limitations and pain. A further aim was to describe what types of activity the interventions were based on and to determine the quality of the evidence using the GRADE assessment.

Methods

In this review, we included only randomised controlled trials with a detailed description of the intervention in terms of frequency, duration and intensity, and outcomes related to cardiorespiratory fitness, muscle strength, activity limitation and pain. Requirements for inclusion were a frequency of exercise of at least two sessions per week, each session lasting a minimum of 20 min, total duration of at least 6 weeks, with an intensity of at least 40–50% of the maximal oxygen uptake (VO2max), and/or at least 30–50% of one repetition maximum (1 RM). Interventions of 8–26 weeks were classified as short-term, and interventions lasting 52 weeks or longer as long-term. The interventions included warm-up, aerobic and or muscle strengthening exercise, and cool-down periods of various lengths within the total session time.

The literature search was performed in September 2015 in the following databases: PubMed, Cinahl (EBSCO), Cochrane Central (Wiley), Swemed+ and Pedro. The two authors independently selected articles based on title and abstract, checked for fulfilment of the inclusion criteria, and then had discussions to reach consensus on which articles fulfilled the requirements for inclusion. A total of 17 articles fulfilled the requirements for inclusion. Quality of evidence was assessed using the GRADE Working Group grades of evidence (high quality, further research is very unlikely to change our confidence in the estimate of effect; moderate quality, further research is likely to have an important impact on our confidence in the estimate of effect and may change the estimate; low quality, further research is very likely to have an important impact on our confidence in the estimate of effect and is likely to change the estimate; very low quality, we are very uncertain about the estimate). The authors independently graded the quality of evidence in the selected articles and then had discussions to reach consensus on the grading of the quality of evidence. An associate professor of physiotherapy (Helene Alexanderson) graded a random selection of five articles, and a discussion was held between her and the authors to reach consensus on the grading. Four groups of exercise programmes previously described in the Cochrane review by Hurkmans et al43 were used as the basis for describing the type, and analysing the quality, of evidence.

Results

Effects of short-term land-based aerobic exercise

There is moderate-quality evidence (GRADE, +++ strength of evidence) that short-term (8–12 weeks) land-based aerobic exercise 3 times/week, 30–75 min per session at moderate to high intensity (at least 40% of VO2max with progression up to 65% of VO2max)22–25 can improve cardiorespiratory fitness, but not increase muscle strength, immediately after the intervention is completed (table 1). There is low-quality evidence on how activity limitations and pain are affected (GRADE, ++ strength of evidence) (table 2). In the studies of Baslund et al22 and Harkcom et al,23 the interventions consisted of bicycle ergometer exercise. The study by Baslund et al22 examined the effects of a bicycle ergometer interval exercise intervention, with continuous testing of cardiorespiratory fitness to confirm that the correct intensity was applied. The Harkcom et al23 intervention was designed to compare three bicycle ergometer programmes of different total length of exercise time, rate of progression and total duration of activity. The study of Minor et al24 examined the effect of aerobic walking on an uneven course, and in the study by Neuberger et al25 the intervention consisted of low-impact aerobic exercise performed under supervision or as home exercises using a videotape programme.

Table 1

Description of the exercise and control group interventions and summary of the results from 18 randomised controlled studies on aerobic and/or strengthening exercises

Table 2

Summary of effects and recommendations of aerobic and muscle strengthening exercise in RA

Effects of short-term water-based aerobic exercise

There is moderate-quality evidence (GRADE, +++ strength of evidence) that short-term (8–12 weeks) water-based aerobic exercise 3 times/week, at least 60 min per session at moderate to high intensity (at least 40% of VO2max with progression up to 80% of VO2max)25 ,32 ,33 can improve cardiorespiratory fitness immediately after the intervention is completed (table 1). There is low-quality evidence on how muscle strength, activity limitations and pain are affected (GRADE, ++ strength of evidence) (table 2). In two of the studies, the interventions were carried out in temperate pools (32–36°C),32 ,33 and, in two studies, participants were specifically trained to control their own pulse in order to control intensity.25 ,32 The Hsieh et al33 study describes how warm-up was performed on a bicycle ergometer while the other two interventions25 ,32 were performed only in water.

Effects of short-term land-based aerobic and muscle strengthening exercise

There is moderate-quality evidence (GRADE, +++ strength of evidence) that short-term (12–26 weeks) land-based aerobic and muscle strengthening exercise 2–5 times/week, 30–80 min per session at moderate to high intensity (at least 40% of VO2max with progression up to 75–80% of VO2max and with progressive increase up to 70% of 1 RM)26–31 can improve cardiorespiratory fitness and muscle strength immediately after the intervention is completed (table 1). There is low-quality evidence on how activity limitations and pain are affected (GRADE, ++ strength of evidence) (table 2). The aerobic parts of the interventions were based on bicycle ergometer exercises,26–30 treadmill or rowing ergometer exercises,28 or walking,31 and the strengthening exercise was based on functional exercises26 ,27 ,30 ,31 or gym machines.28 ,29 One of the studies offered individualised exercises: the study by Stavropoulos-Kalinoglou et al28 ,29 used the patients’ preference and perceived ability to determine the type of aerobic exercise mode.

Effects of long-term land-based aerobic and muscle strengthening exercise

There is moderate-quality evidence (GRADE, +++ strength of evidence) that long-term (52–104 weeks) land-based aerobic and muscle strengthening exercise 3 times/week, 30–75 min per session at moderate to high intensity (at least 40% of VO2max with progression up to 85% of VO2max and with progressive increase up to 70% of 1 RM)21 ,34–37 can reduce activity limitations and improve cardiorespiratory fitness and muscle strength immediately after the intervention is completed. Moreover, muscle strength can be maintained over time (table 1). There is low-quality evidence on how pain is affected (GRADE, ++ strength of evidence) (table 2). In the study by van den Berg et al,21 ,37 exercise was performed at home and supervised through the internet; the aerobic part was based on bicycle ergometer exercise and the strengthening exercise was performed using rubber expanders. In the study of de Jong et al,34 ,35 the intervention was supervised in the clinic; the aerobic exercise consisted of bicycle ergometer exercise and sport or games, and the strengthening part was based on circuit interval training. In the study by Hansen et al,36 the aerobic exercise was individualised to one of swimming, cycling, running or jogging, and all patients also performed a 15 min strength training programme.

Discussion

The results of the present study extend those from the 2009 Cochrane review.43 No differences are found regarding the outcomes on cardiorespiratory fitness and muscle strength, but the quality of evidence is verified by a larger number of studies. However, we consider the evidence for short-term water-based aerobic exercise affecting activity limitations to be of low quality. This might be the result of using different definitions of activity limitation or including different studies in the review.

Clinical implications

There is still not enough evidence to support a dose–response relationship between, on the one hand, the dose of aerobic or muscle strengthening exercise and, on the other hand, the effect on, for example, activity limitation, cardiorespiratory fitness, muscle strength and pain. In nine of the included land-based interventions,21–23 ,26–30 ,34 aerobic exercise was based on bicycle ergometer training, which is a low-weight-bearing type of exercise. Implementing this type of exercise in clinical practice, in public gyms or at home might thus seem relatively easy, as this equipment is common. However, weight-bearing exercises such as aerobics, aerobic walking, treadmill exercise, jogging or running can also be performed to improve cardiorespiratory fitness. Exercise in water can result in improved cardiorespiratory fitness; however, only one of the included studies described the intervention in detail (type of movements, water depth, equipment, etc).32

In most studies, there was a lack of reporting how intensity was controlled during exercise, either by the participants themselves or by others. To enhance individuals’ abilities to perform exercise at the recommended intensity independently of healthcare professionals, there is a need for a mutual understanding of the concept of intensity, as well as useful tools for self-monitoring of intensity (eg, Borg RPE scale, pulse watch).

Strengths and limitations

This review included 17 studies, showing that the body of research in the area has grown since the last updated Cochrane review, which included eight studies.43 The present review does not meet the highest standards of systematic methodology, and the 17 studies included might not all qualify for inclusion if a Cochrane review were to be repeated. However, we believe that the search procedure can be considered systematic, allowing for studies to be included. The inclusion criteria were strict, demanding very clear descriptions of frequency, duration and intensity, which led to exclusion of several studies. Other limitations of the study lie in the lack of meta-analysis and the fact that no other data were requested or used than what were available online. Earlier reviews have focused more on whether the exercise was supervised or not, an aspect to which we have paid very little attention in the present review. This might still be of interest, and more research is needed to determine the optimal type of exercise for patients with RA.

What are the findings?

  • Short-term land-based aerobic exercise of moderate to high intensity improves cardiorespiratory fitness in rheumatoid arthritis (RA).

  • Short-term water-based aerobic exercise of moderate to high intensity improves cardiorespiratory fitness in RA.

  • Short-term land-based aerobic and muscle strengthening exercise of moderate to high intensity improves cardiorespiratory fitness and muscle strength in RA.

  • Long-term land-based aerobic and muscle strengthening exercise of moderate to high intensity reduces activity limitations and improves cardiorespiratory fitness and muscle strength, and muscle strength can be maintained over time in RA.

How might it impact on clinical practice in the future?

  • Individuals with rheumatoid arthritis of low to moderate disease activity can participate in exercise to improve cardiorespiratory fitness and/or muscle strength without deterioration of the disease and should be encouraged to participate in the type of exercise that they find enjoyable.

  • Water-based exercise is a safe and effective way of increasing cardiorespiratory fitness, but the duration of the exercise needs to be at least 60 min per occasion.

Acknowledgments

The present article is a shortened and updated text based on a chapter in the upcoming Swedish book Physical activity in the prevention and treatment of disease (FYSS 2015), Professional Associations for Physical Activity, Sweden. We would like to acknowledge Professor Christina Opava, Division of Physiotherapy, Karolinska Institutet, for the access to the 2008 edition of the FYSS, Associate Professor Ralph Nisell, Department of Rheumatology, Karolinska University Hospital Solna, for updating the medical treatment parts, and Associate Professor Helene Alexanderson, Department of Rheumatology, Karolinska University Hospital Solna for participating in the quality grading of the articles.

References

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Footnotes

  • Contributors ES and NB both performed the literature search and quality grading and wrote the manuscript. Both also revised the manuscript and approved the final version.

  • Competing interests None declared.

  • Provenance and peer review Not commissioned; externally peer reviewed.

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