LOL I hear you. I have 2 English Mastiffs a cattle dog and a chihuahua. By the time I walk all the dogs in a day I get plenty of cardio in.
We just got a treadmill yesterday so I popped the chihuahua on it behind me and she liked it. But I had to go super slow or she shot off the back..lol. So I put her off and she ran around it sniffing and trying to figure out how to get on and I had to slow it down or I was afraid she would get hurt, so she jumped on..lol
I finally picked her up and did it holding her because she was toooo slow!!!