Exercise is often ineffective as a short-term pain killer for patients with chronic pain

When healthy people start to exercise, the brain activates powerful descending analgesic systems (pain inhibitory actions). This leads to increased pain thresholds during exercise, making it less likely that we will feel pain during, or immediately following, exercise.  However, brain-orchestrated analgesia or pain inhibition is often impaired in people with chronic pain and central sensitization. This applies to exercise-induced activation of brain-orchestrated analgesia in chronic pain patients as well. Aerobic exercises like bicycling do not activate brain-orchestrated analgesia in patients with fibromyalgia, chronic whiplash associated disorders, or chronic fatigue syndrome. Remarkably, chronic low back pain patients are able to activate their brain-orchestrated analgesic systems normally during exercise.

Likewise, local muscle contractions activate generalized analgesia in healthy, pain-free humans and patients with either osteoarthritis or rheumatoid arthritis, but result in increased generalised pain sensitivity in fibromyalgia patients. In patients having local muscular pain (e.g. shoulder myalgia), exercising non-painful muscles activates generalized analgesia. However, exercising painful muscles does not activate brain-orchestrated analgesia either in the exercising muscle or at distant locations.

The precise mechanism underlying the dysfunctional response of the central analgesic systems to exercise in some patients with chronic pain remain to be revealed, and are the subject of ongoing research. If we understand it better, we might be able to treat it, which in turn should lead to more effective exercise therapy for these patients.

About Jo

Dr Jo NijsJo Nijs holds a PhD in rehabilitation science and physiotherapy. He is a researcher and assistant professor at the Vrije Universiteit Brussel (Brussels, Belgium) and the Artesis University College Antwerp (Belgium), and he is a physiotherapist at the University Hospital Brussels. His research and clinical interests are patients with chronic unexplained pain/fatigue. He has (co-)authored more than 100 peer reviewed publications and served over 40 times as an invited speaker at national and international meetings.


Nijs J, Kosek E, Van Oosterwijck J, & Meeus M (2012). Dysfunctional endogenous analgesia during exercise in patients with chronic pain: to exercise or not to exercise? Pain physician, 15 (3 Suppl) PMID: 22786458

Link to the full text paper: http://www.painphysicianjournal.com/2012/july/2012;15;ES205-ES213.pdf


  1. Kathryn Larvinson says

    Interesting article on exercise and chronic pain conditions

  2. Hi Jo. There’s some fantastic advice in this post. Extremely useful for anyone who’s suffering from issues with chronic pain.

    Keep up the good work.

    Best wishes, Alex

  3. Tommy (In Chronic Pain) says

    Exercise is one of the biggest problems for people with Chronic Pain. A Vicious cycle of inactivity, stiffening joints and muscles, increased weight, increased pain and back to less exercise Is what i think puts most people into a downward spiral. If it is not broken early on, the sufferer may open them self up to a host of related issues. I just recently covered this subject on my own Blog, you can find the post here:

  4. Mike, I like what you say but I do not think that they are fusion failures as in the fusion is mechanically failing. It is 80,000 people a year with failed back surgery syndrome – chronic disabling pain persisting after surgery – still an astonishing amount given the way ortho consultants can sometimes groom patients for proceedures like PLIF. Still thanks for flagging that stat up which I will use to dissuade chronic pain patients from surgical intervention.
    Kind thoughts,

  5. Mike Caruso says

    I appreciate this work by Jo Nijs and team!!

    The table in the article with guidelines for exercise when central sensitization (CS) is a factor makes good sense. I will include it in an appendix to my FCE reports.
    Here is the US we tend to use opioids lots. The low back pain patients on opioids seem to look more like patients with “fibromyalgia, chronic whip disorders and chronic fatigue syndrome”.
    I wonder if long-term use of opioids shifts the balance toward CS.
    The outcomes from spinal fusion for degenerative lumbar spine is poor for injured workers (NguyenT, Spine, 2011). I wonder what influences these outcomes: the LT opioid use, or the questionable logic of fusion (physio-pedia.com, low back pain: possible mechanisms), or the approach to the patient (often assumed work avoidance), or the exercise program (commonly quota based), or other factors (Nortin Hadler).
    Many of these patients would be far better off having not been subjected to the fusion or the LT opioids (Robert Barth), and had better approaches to their exercise program…and there are a lot fusion failures- 80 thousand a year (Ragab A, 2008).

    These guidelines make sense for many difficult patients.
    “The tests of truth are logical consistency, agreement with experience, and economy of explanation.” (Robert M. Pursig, Lila, ch 8).

    Thank you Jo Nils and team.

  6. Hi! I’m from Spain, student of physical therapy. Recently I read this article…
    Is inflammation a mitochondrial dysfunction-dependent event in Fibromyalgia?
    “…Both mitochondrial dysfunction and inflammation have been implicated in the pathophysiology of FM. We have investigated the possible relationship between mitochondrial dysfunction, oxidative stress and inflammation in FM…”
    Is it possible that the aerobic exercise do not activate the system central analgesic for this reason?
    Best regards