Plumbers pick their own work conditions as they are often self employed. So uh kinda? Mostly not. Heavy things are still heavy and still need to be lifted. You're probably not going to bring in a jack.
My best friend was a HVAC repairman and is a programmer now. He's happier as a programmer. Some people are happier as an HVAC repairman, and more power to them. However it's not the norm for people who have done both.