Hah yeah I think I was told to rein in on the miles since I am used to running miles and miles everyday. I could walk after day one and did but was told not to overdo it, to the point he even gave me a distance limit. Now I have to relearn how to run...no more slouching. Yay. I hear you guys on the dog walking...we have two little poodles. One is mine and I am very thankful I trained her to walk next to me so I can walk her hands free by tying her leash to my belt/belt loop. Very useful. And she despises running so she keeps me in check lol.
All in all none of us can really advise you on exercise restrictions since each surgeon has different restrictions. Ask your surgeon since there is normally a clause in the surgery agreement about complications and revisions not being covered if you don't follow the surgeon's post-op care and restrictions. A lot of surgeons have varying restrictions and restrictive periods.
Most of the six week periods are based off of the far end of the average healing time for people in general. You'll see six weeks quoted a lot for healing times, such as piercings and tattoos. Even though those types of things don't really register as a big deal they really do put a strain on your system as it heals. A lot of times you'll be told to avoid caffeine and alcohol as much as possible and to be "chill" until healing has completed, on average one and a half to two months (6-8weeks).
I believe there is some truth to the cardio thing personally. I have tattoos and piercings, some I got before I started being diligent about running and some after. The ones before I was running everyday never swelled, almost at all. Kind of freaky hah, like my near zero swelling after top surgery. Now the second and third part of my forearm tattoo were done after I had been very diligent in my running (minus down time for my hysterectomy and kidney surgeries) and both swelled excessively, especially the third time which was weird since it was the least time I'd ever spent in the chair. The only thing that changed was the running every morning. So at least for me I believe being as chill as possible about the cardio is the way to go to promote a good healing period.
Also don't forget the vitamins and veggies.

I think I'm driving people around here insane with my health nut diet.