HI Sandi,
I am 8 days post op and finding energy comes back little by little. I would say be careful not to over do it. Like an idiot I had appointments I couldn't cancel on day 6 post op and walked almost 7000 steps mostly outside in the heat. Needless to say I felt wiped and dehydrated the next day. Its taken my three days to recover from that.
I asked the surgeon about they energy at the post-op and this what they explained to me. My cuts are laprascopic so they said I have little cuts on the outside but big ones on the inside. 50% of our energy is going to healing from our major abdominal surgery. The other 50% is keeping us alive and doing our body functions. When we go for walks that 50% of energy keeping us alive and running our bodies is cut even further. Then you add the lower caloric intake to the equation. Thats why they say short walks because you will burn your energy quicker and run out sooner.
I was worried too but this made perfect sense to me once explained. I hope this helps!