Which exercises relieve pain, and how much pain is safe?

Why exercise relieves pain at all. It restores movement to stiff joints, reduces the protective muscle guarding that builds up around a painful area, improves circulation through healing tissue, and over several weeks it reduces how sensitive the nervous system has become to that area. That last one is why exercise helps pain that has been present for months, when nothing is torn or inflamed any more.

A safe ache is dull and spread over the muscle. It is there during the exercise and for a few hours after, it has settled by the next day, and it is no worse at the next session. Often it eases once you start moving.

The warning signs are different: sharp or stabbing pain, pain that climbs steadily as you continue, new numbness, tingling or weakness, pain spreading further down an arm or leg, a joint that swells after the session, and soreness still there two or three days later. Any of those means stop that exercise and have it looked at, not push harder.

How to start. Begin at a level that feels too easy. Change one thing at a time every week or two, either repetitions, sets or weight, never all three. Expect four to six weeks before you can judge whether a programme is working, and keep a one-line note of pain out of ten each session, because slow improvement is invisible day to day.

Pain and damage are not the same thing. Once tissue has healed, pain can continue because the system has stayed sensitive. In that situation gradually doing more, rather than resting more, is the treatment.