I walk for 1hr on a treadmill set to 4mph and 4deg incline. My heart rate gets up to 150 bpm by the end. Used to run but was always getting sore knees. Now I w

I walk for 1hr on a treadmill set to 4mph and 4deg incline. My heart rate gets up to 150 bpm by the end. Used to run but was always getting sore knees. Now I walk and it’s very consistent.