Haven't seen anyone mention it, but a more recent, low impact excersize I've picked up recently is golf (walking, no cart, no caddy). I'm currently working of a project that's going on a year behind schedule, and Monday was the third week in a row of a meeting posponed last minute due to collegues having scheduling conflicts that were existing, but not disclosed until late enough to waste an hour of everyones time. Instead of maintaining a few more hours of poor posture at my sitting desk for a noon reschedule, I took off a half day and golfed 18 holes while enjoying the eclipse. My advise: make sure you jog a few miles in the morning, then do your best to tolerate the dangerous sitting posture of your 5 hour work day. OK, now that you've had just about enough sitting for one day, how about a nice afternoon of golf to strech out that lower back?
Maybe I exagerated, I just know how easy it is to use your muscle and limb chains badly and then stop because it hurts somewhere.
My advice was to start very slow, and avoiding heel is a trigger to think of landing as absorbing, using your calves at first.
I invite you to read literature on the subject:
1. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2556152/?tool=p...
2. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2743580/
3. https://www.ncbi.nlm.nih.gov/m/pubmed/16932832/
Note: I am not a doctor, and the literature becomes mixed as you study runners with higher and higher mileage per week. The point is that someone with a healthy weight should not be damaging their joints merely by repeatedly running - proper running involves allowing your feet to fall below you, not ahead of you, where the calves and quads can properly absorb the impact and use the "bounce" from the ground impact to propel forward efficiently. Doing something other than this, like landing on your heel in front of your body, forces your knees to absorb the impact.
If you're running 60, 70 or 80 miles per week there may be degenerative effects on joint health, but if we're speaking realistically that is unlikely to happen for someone just looking to get into shape unless they're a few years in and training for something. I run 30 miles per week and have no plans to significantly increase my mileage - my health and fitness goals are rather more "intense" than most people I know and it takes up a lot of my time (looking at about an hour of running workout per day).
If someone wanted to gain the benefits from jogging, jogging to the store or even commuting by running five days a week would be far, far lower than what appears to be the lower bound on introducing joint degeneration.
I'm going to echo the grandparent comment: if you're not already moving and have a favorite exercise (cycling, swimming), I urge you to consider running. Running every day quite literally changed my life. Dieting is a close second. My mood significantly improved, my sleep improved, every physical activity felt better, etc. After a month of consistent running you even miss it when you don't do it.