It sounds like they're just being overworked. So, just have the nurses take a 20 minute break every 2 hours, to go out and take a walk. The hospital can require it if it comes to that but why wouldn't they just want to do it? and if the hospital doesn't want to do it, then the nurses should insist on it and walk off the job if not given their breaks. I would imagine the hospital would rather agree to 20 min breaks every 2 hours rather than loosing 90% of their workforce forever: they don't have a choice, they have to agree.