Does daily walking wear out an arthritic knee faster, or is it actually protecting it?

Diagnosed with osteoarthritis in my right knee in March, 58 years old, X-ray showed the wear is on the inner side. The one thing I've kept up my whole adult life is a morning walk with the dog, about 3 miles, and now I'm frightened of it.

My brother-in-law (not a doctor, obviously) said a knee is like a tyre, only so much tread on it, and every mile I walk is using it up. That's been sitting in my head for weeks. The knee does ache on the last stretch home and again in the evening, so part of me thinks he must be right and I should be SAVING what cartilage I've got left.

But then I read that exercise is supposed to be good for arthritis, which seems to be the exact opposite advice. So which is it? Does walking wear an arthritic knee out faster, or protect it? And is the aching while I walk a sign I'm doing damage, or just what arthritis feels like? I'd rather hear it from people actually living with this than from the tyre expert at Sunday lunch.

Dennis, the tyre thing is nearly word for word what a new lady in our walking group said last month, so you're in good company with that fear. Nine years of arthritic knees here and walking is the thing that's kept me going, not the thing that's finished me off.

The one time I did stop properly, a bad winter a few years back where I barely walked for two months, was the worst my knees have ever been. Stiffer, weaker, and the first walks back were miserable. That taught me more than any leaflet.

What I have changed is the HOW, not the whether. Two shorter walks beat one long one, I keep to flatter routes when the knee is grumbling, and I use poles on anything with a slope. My rule of thumb is the next morning: if the knee is back to its usual self by then, yesterday's walk was fine. If it's swollen and cross for a couple of days, that walk was too big and I shrink the next one rather than stopping altogether.

I'll give you the short version of my expensive lesson: after a bad flare I rested mine for the best part of three months, properly rested it, and it got worse, not better. The muscles went, the knee got lazier, and everything hurt more with less. Resting an arthritic knee long term is the one thing I'd never do again. Keep moving, just be cleverer about it than I was.

Worth answering Dennis's question head on, because the tyre analogy does real harm. For the great majority of people with knee osteoarthritis, regular walking does not wear the joint out faster. The evidence points the other way: people who keep walking tend to hold onto function longer and hurt less than people who rest, which is why exercise sits at the top of every major guideline as a core treatment, not an optional extra.

The tyre picture fails because cartilage is living tissue, not tread. It has no blood supply of its own; it feeds by soaking up nutrients from the synovial fluid, and it is the rhythmic loading and unloading of walking that pumps that fluid through it. On top of that, walking keeps the quadriceps and the other muscles around the knee strong, and strong muscles act as shock absorbers that reduce the load the joint itself takes. An arthritic knee that stops moving loses both of those protections at once, which is exactly what Maureen describes.

On dose, honest numbers rather than false precision: something in the region of 150 minutes of moderate activity a week is the usual target, and in knee osteoarthritis specifically, daily step counts around the 6,000 mark have been associated with maintaining function. It does not have to arrive in one heroic outing; Sue's two shorter walks are a perfectly good way to bank it. As for the aching, the distinction I draw in clinic is between soreness and harm: an ache during a walk that settles by the next day is the arthritis talking and is generally acceptable, while a knee that swells and stays irritable for 48 hours or more is telling you that particular dose was too much for it at the moment, which is a reason to shrink the walk, not abandon it. The background to all of this, what the disease actually is and what makes it progress, is set out in the site's guide to knee osteoarthritis, and it is worth knowing that carrying extra weight moves the needle far more than mileage does.

The exceptions matter as much as the rule. A knee that locks, gives way, becomes hot and swollen, or changes its behaviour suddenly is not a "walk through it" situation, and inflammatory conditions such as rheumatoid arthritis play by different rules during a flare. None of this replaces an assessment of your own knee: a physiotherapist or your own doctor is the right person to turn these ranges into a plan for you.

Only thing I'd add to that is surfaces and shoes, which nobody mentioned. I get on much better on the canal towpath than on pavement, and switching my stiff old boots for cushioned trainers made a bigger difference to the walk home than I expected. Cheap experiment, worth a go before you go changing anything else. (One thing at a time though, see my exercise thread for how long it took me to learn that.)

Seven weeks on, reporting back since this thread talked me off the ledge. Kept the walking, split it into two shorter loops most days, softer routes where I can, and I've been using Sue's next-morning rule to judge it.

The knee still aches, nobody promised otherwise, but it settles overnight almost every time and I've had one proper flare in seven weeks instead of one a fortnight. Seeing a physio next month to get the strength work looked at properly. Mostly I've stopped being afraid of my own dog walk, which is worth more than I can say. The tyre expert has been informed.