How to exercise in different chronic pain conditions?
After a very interesting discussion on exercise prescription for chronic low back pain on a previous post on chronic pain, I received an invitation to write a blog on exercises for chronic pain which I accepted to write. For writing this blog, I performed a narrative review of literature and summarized the evidences for three common chronic painful conditions. Exercise in low back pain will warrant a separate blog post.
Chronic pain is a feature of many disorders such as osteoarthritis (OA), fibromyalgia (FM), chronic low back pain (CLBP), headache, chronic fatigue syndrome (CFS), Chronic Whiplash associated disorders (CWAD) etc. It affects 11% to 55% of the general population. Chronic pain is considered one of the biggest burdens for the health care system, is troublesome to the patients and extremely difficult for the clinicians to manage because of the complexities associated with it. Chronic pain can be managed by cognitive functional therapy, pacing, coping strategies etc. However, exercise is the cornerstone for the management of chronic pain.
Exercise is defined as “planned, structured, and repetitive bodily movements that are performed to improve or maintain one or more components of physical fitness.” Large number of guidelines support exercise therapy as the main-stay for the treatment of chronic pain. The aim of exercise is to relieve pain perception, fatigue and depression, and improve physical fitness and quality of life. Exercise can place both positive and negative responses to the individuals living with chronic pain. Thus, there is a small margin for error in chronic pain while prescribing exercises in this population. This article summarizes guidelines or recommendations for prescription of exercises in chronic pain conditions. Please note these exercise guides are just to guide your clinical practice, not to dictate it.
Response to exercise in chronic pain:
Favorable Responses: In healthy individuals and patients with OA or Rheumatoid Arthritis (RA) or CLBP, activation of central pain inhibitory mechanisms for upto 30 minutes post-exercise is seen with aerobic exercise of at least 70% of the maximum aerobic capacity. This is known as exercise induced endogenous analgesia (EA). Resistance training also triggers EA but the effects last for only up to few minutes post-exercise. In local muscular pain, exercising the non-painful muscle induces EA but exercising the painful muscle has no therapeutic effect. Proposed mechanism for this EA includes the release of endorphins, opioids, growth factors, activation of opioid receptors and supraspinal nociceptive inhibition.
Unfavorable Responses: In some patients with chronic pain disorders, dysfunction in the activation of central pain inhibitory mechanism has been observed. Some patients such as those with FM, CFS and CWAD report increase in pain and other symptoms after aerobic exercises due to central pain sensitization. This can lead to low compliance among these subgroups of patients and they tend to skip or quit the exercise sessions.
How to prescribe exercise in individuals with dysfunctional Endogenous Analgesia?
• Opt for aerobic exercises over isometric or eccentric exercises.
• Exercise non-painful parts of the body.
• In cases such as fibromyalgia, use low intensity training.
Precaution: Inadequate recovery leads to accumulation of stress over time resulting in increase of symptoms. Exercise activates stress responses which are proportional to the intensity and duration of exercise. This stress, when balanced with recovery periods; results in homeostatic balance in sympathetic nervous system and adrenal-hypothalamo-pituitary axis. So, high stress levels are not detrimental as long as the person engages in sufficient self-initiated recovery activities.
- Recovery activities (eg: going out for jogging, meditation, sleep, social contact) should be individualized and backup strategies should be available in case the primary strategy fails.
- During the recovery phase, there is heightened sensitivity towards disturbances, so there should be no interruptions.
- After a successful recovery too, if a person is confronted with noises, negative feedbacks about their performance, it will greatly affect the subsequent performances.
- It should be noted that in individuals with dysfunctional EA, the recovery time is increased.
Guide for Migraine and Tension type Headache:
Both these types of headaches have been associated with physical inactivity. Sub-maximal aerobic exercise for 40 minutes, 3 times a week, including a warm-up and cool down phase is beneficial in reducing the frequency of migraine attacks through EA also reduces depression and anxiety. However, upto 44% migraine patients report exercise to be a triggering factor and some report increase in pain during an attack which may be due to changes in central perception of pain. Some studies suggest that exercises should be performed between migraine attacks, while others found exercising during the onset of headache may help reduce the migraine attack. Habituation decreases the risk of migraine attack so it is better to progress the exercise slowly than to avoid it completely. In chronic tension type headache, shoulder and neck muscle strengthening is the best option and results in decreased intensity and frequency of headaches.
Guide for exercise in Chronic Knee Osteoarthritis:
Currently there is no one best treatment for knee OA. However, a very recent Cochrane review by Fransen et al suggests exercise to improve muscle strength can limit the onset and progression of OA, decrease pain intensity and improve physical function. Poor physical fitness has also been reported among people with knee OA.
Apart from exercise, manual therapy has some proven benefits for reduction in pain and improvement of function.
“High-quality evidence shows that among people with knee OA, exercise moderately reduced pain immediately after cessation of treatment and improved quality of life only slightly, without an increase in dropouts. Further research is unlikely to change the estimate of these results. Moderate-quality evidence indicates that exercise moderately improved physical function immediately after cessation of treatment. Further research may change the estimate of these results.”
Guide for exercise in Chronic Whiplash Disorder:
Dysfunctional exercise induced analgesia, central sensitization, post-traumatic stress, dysfunctional stress response system, impaired cervical neuromuscular control, and maladaptive pain cognitions are all features association with CWAD. A comprehensive exercise consisting of specific motor relearning exercise, graded activity and cognitive behavioral treatment (addressing stress management) is a “state of the art treatment approach” for CWAD based on current understandings. Changing patient’s beliefs about pain is a must for treatment of CWAD. The role of exercise remains important but when and how to give the exercise remains uncertain.
Precautions are needed when prescribing exercise to chronic pain patients and the exercises must be individualized based on their assessment and response to exercise. In addition to exercise therapy, cognitive therapy should also be included during intervention for superior results.
1. Daenen L, Varkey E, Kellmann M, Nijs J. Exercise, not to exercise, or how to exercise in patients with chronic pain? Applying science to practice. Clin J Pain. Feb 2015;31(2):108-114.
2. Fransen M, McConnell S, Harmer AR, Van der Esch M, Simic M, Bennell KL. Exercise for osteoarthritis of the knee: a Cochrane systematic review. Br J Sports Med. Sep 24 2015.
3. Nijs J, Ickmans K. Chronic whiplash-associated disorders: to exercise or not? Lancet. Jul 12 2014;384(9938):109-111.
About Anupa: She is a final year Bachelor of Physiotherapy student studying at Kathmandu University School of Medical Sciences, Nepal. She is passionate about musculoskeletal physiotherapy. She is interested in studying the psychosocial aspects of pain, especially illness perception, which are can contribute to musculoskeletal pain.