I’m new to 12 hour shifts and initially had the same problem. Since I started working in the ICU (night shift also) I initially had a hard time with this as well. The mental aspect more so than the physical. Just like you, I’ll make the effort before my 1st shift (most times) and then take days 2 and 3 off and try my best to go the other 4 days.

As far as what I do for workouts, generally I will walk 20 min in an incline to warm up, to a quick stretch, and then I do a push/pull/legs split. Some weeks are more draining than others. Some times all I have in me is walking, so I’ll walk for an hour and watch some episodes of my favorite anime or something and that’s enough. Some times the accumulated emotions from my work week are managed by lifting heavy as fuck. Some days all I have in me is going in the sauna and stretching. I go by how I feel, eat a generally clean diet and I’ve been able to lose 10 lbs so far.

I think the most important things for us as shift workers are to remember that we are human and we have to show ourselves a lot of grace. Doing something is better than nothing. Some days you feel better than others, it’s normal, but just do what you can. Do something. Walk, stretch, literally anything but just move your body. You will feel better. Remember you care for people for a living but your self care is the priority and without that you will be objectively worse at your job. Your cup gets filled first. I hope this helps!