Hey T.C.
I'm eight weeks post-op (gastric bypass) and I've started working out. I'm 65. Have no blood pressure/cholesterol issues-thankfully! My starting weight before surgery was 311. I'm now 270 -in just 8 weeks. I'm super excited about that.
What I would suggest since your calorie level is so low is to do a 30-minute walking routine. Once you start with solid food, I would then up the work out to a non-stop work out. To give you some idea, here's what I do.
Monday, Wednesday and Friday: Warm-up (that time doesn't count against my total allotted time) When I feel warmed up, I work upper body with a weight that I can handle and I do around 3 to 4 sets of each body part with 12-14 reps per set. As I add weight, I drop my reps by two. So: 14, 12, 10 etc. Right after I've done my sets, I hit a heavy bag for 3 minutes and then immediately go to my upper body routines. No resting. That's the key part.
Tuesday, Thursday: I do cardio only...Seven minutes on a treadmill with a pretty steep incline and a higher pace...then hit the heavy bag for another 3 minutes and then go right back to the treadmill.
You're probably wondering why I don't work legs. At my age, I have to bum knees and don't want to do too much to aggravate them. Not to mention, four months ago I had a total shoulder replacement and so the weight training works perfectly with my shoulder rehab.
I hope that helps!