On your next hospital visit for life-saving care, I'm sure you will be comforted to know that nurses (in the US) typically work 12 hour shifts and they're on their feet the whole time.
I’m sure it varies by location, but my nurse friends only work 3x12, giving them 4 days off per week. Working 12 hour shifts is much more acceptable when you have more days off than days spent working. They’re virtually unavailable on days they work, but then they’re off traveling or having fun for 4 days, some times more if they combine their days off back to back. My close nurse friend routinely takes week long vacations without actually taking any time off at all.