Im on my feet for much of my 12 hour shift (I teach ICU, staff nurse ED). Typically get in about 10-15k steps each shift or more. I always ask for help lifting people. Some of it is mental exhaustion as your brain is often always “on” especially the first few years as you have to think through everything so much.
Yes, ultrasound and dietitian is mostly sitting or standing around but also a bit more repetitive doing the same things over and over again.