Just realized that Zone one heart rate in Wahoo SYSTM workouts is defined as Z1 (0-xxx). I wonder how somebody can do a workout with a heart rate below say 30-40? What about heart rate equal to 1? 
With heart rate of 0 you are essentially dead.
Some people get pretty low though:
Tom Pidcock’s HR during Stage 4 of the Tour was insanely low - Canadian Cycling Magazine
I understand that elite pro riders may have insanely low heart rate even under a significant load. I just wanted to point that having 0 in the acceptable heart rate range looks strange.
I agree,but you have to start somewhere. I think min would be better and undefined.