Exercise and treatment induced arthralgia (pain and stiffness in the joints).

The newsletter content this week is on the benefit of exercise and arthralgia, which refers to joint pain and stiffness caused by medications like aromatase inhibitors.  

The quick summary, some people who experience these symptoms have shared with me that they are worried exercise may make their symptoms worse. But – research publications suggest that exercise and physical activity are safe and can reduce pain and stiffness. 

The detail: people who perform more physical activity often report less pain and stiffness compared to people who perform less. And people who complete exercise interventions will also report a greater reduction in pain and stiffness compared to people who do not complete exercise interventions. This often includes improvements in both average pain and worst pain. In addition, performing exercise can reduce your sensitivity to painful stimuli. That is, if you felt something that was painful before a run or bike ride – like touching something hot or cold – you would perceive it as less painful and more tolerable after a run/ bike ride.  

What type of exercise is best? For some conditions we know a specific type of exercise is best – because different types of exercise affect different bodily systems (like aerobic exercise for blood pressure or resistance training for insulin sensitivity). But it is hard to say with pain as pain is so complex. And because there aren’t lots and lots of research studies in this area. One of the highest quality studies specific to arthralgia in women with breast cancer featured both resistance exercise and aerobic training and found performing 150 minutes per week of supervised exercise resulted in a 30% improvement in pain scores. Some other types of research – like animal studies – stress the importance of voluntary and self-directed exercise for maximum pain benefit. And observational studies – including studies I have conducted – show initial benefit with just a small amount of regular physical activity like walking and running for transport or leisure. So, at this stage the best recommendation we can give is to choose an activity you like and do it regularly.  

How does exercise benefit pain? Again it is hard to say as pain is so complex. It is likely that exercise can affect pain pathways in the brain and also at the local site of pain. It can also affect some of the risk factors for pain. For example, exercise can reduce fatigue and fatigue increases your sensitivity to pain. Exercise can also prevent against the development of depression, which is one of the biggest predictors of a higher impact of pain. And, finally, exercise - especially voluntarily - can give you a sense of control that can also reduce the way pain is perceived and the size of its impacts. 

UPDATE! How much physical activity should I do to decrease pain?

It isn’t always easy to say ‘how much is best’ as the number is likely to vary for individuals and because the best quality intervention research we have typically compares some physical activity or exercise to none. BUT - in a recent observational analysis I was involved in provides some clues. The best summary I can give – something appears to be much better than nothing. More appears to be a little bit better to something. But much much more doesn’t seem to be that much better than more when we are talking about pain relief. The takeaway: you do not need to do lots and lots and lots of activity to benefit. Something is likely enough to experience some pain reduction. The paper is here: https://acsjournals.onlinelibrary.wiley.com/doi/10.1002/cncr.35208