A daily dog walk is ordinary exercise wearing a lead: twenty to forty minutes of level, repeatable movement, most days, whatever the weather. For a back that stiffens over long still hours, that rhythm does quiet, useful work.

Does walking the dog count as real exercise?
It does. The NHS counts brisk walking toward the weekly activity it recommends for adults, and a dog makes the walk happen on the wet Tuesday as reliably as on the fine Saturday. Pace matters less than regularity: a steady twenty minutes twice a day moves hips, ankles and the lower back through a range a desk never asks for.
What changes the benefit is how you walk. A lead held with shoulders level, a route that includes a slope now and then, and shoes that suit the ground matter more than speed.
What if the dog is stiffer than you are?
An older dog sets its own pace, and that is no bad thing. Sniffing stops and slower miles still move the person holding the lead. If the dog's own joints are the limiting factor, the reading on canine joint health covers how weight management, gentle exercise and supplements such as glucosamine and omega-3 support an ageing dog's hips and elbows.
The same principle applies at both ends of the lead: frequent moderate movement beats occasional heroic effort, for the dog and for the walker.
How do you fit the walk into a stiff working week?
Attach the walk to something that already happens: before breakfast, at lunch, when work ends. A back that has sat for three hours responds better to ten ordinary minutes outside than to a stretch done reluctantly at the desk.
If mornings are the difficult part, our guide to why you feel stiff when you wake up explains what is normal and what is worth checking.
When is a walk not enough?
Walking settles most ordinary stiffness. It does not settle pain that shoots down a leg, numbness, or back pain that follows a fall or comes with a fever. Those need a GP, a few of them urgently: our page on back pain, the plain version lists the red flags.
And if a dog is still on the wish list, our page on joint health as you age covers the human side of the same bargain while you weigh it up.
Sources
For the weekly activity figures used above, see the NHS guide to exercise for adults.