mother nature's stair master

My dog Ollie and I have found our walks on the beach to be full of climbing and ducking trees and branches; such a different shoreline than the east coast. So I think our daily neighborhood dog walks of 2-3 miles, on sidewalks, to be like a stair master set on 2 and our beach walks are like setting it at 7.  What a nice form of functional fitness, being out in nature.