Jumping on the treadmill
Rats are among a group of animals that love to run. Deprive a rat of this opportunity by taking its treadmill away and it becomes depressed, lethargic, sick and very unrat-like.
For rats reared in a limited space without a treadmill, this response, and even mortality, occurs early.
It’s not unexpected then that other animals, like humans, might have a similar response, not necessarily to running but at least to regular and extensive movement.
Today we call this exercise. But in the past it would