Nothing slows a brisk dog walk more then when a dog begins to sniff.
I had one that would turn inside out when she was walking along and smelled fresh deer scent or an antler. And when their nosies are working, their earsies are not. Olfactory input is ignored when they’re asleep, but the slightest sound registers. Whether they respond depends on the noise.
LOL. Ain't that the truth! I had one dog that I just couldn't walk because every square inch of everything had to be thoroughly sniffed. With that dog, if I wanted exercise, it was best to walk alone.