Earlier quoted context omitted.
I don't think exercise was a huge concern in his day. Scheduling times to exercise is a modern invention.
Also, many of the things that qualify today for activity level we would deem "exercise" was reached by everyday chores, such as chopping wood, feeding livestock, walking, &c.
They also died extremely young, so they didn't have to worry about a lot of the diseases that come with not being in shape.