I think in the past people and animals have to work hard for meals and more often they didn't get 'square meals'. Even monks in olden days had to walk a fair way for their one meal a day. (Only in modern days that they do have too much offerings and more time on modern gadgets but little time to burn of Calories.

I read about the Venerable Acharn Cha, who ordered monks to shift a pile of dirt to somewhere else before he went someplace. When he returned, the Venerable said he had changed his mind. He wanted that pile of dirt back it was. It should be clear that Acharn Cha was using exercise to keep his monks busy and healthy!

Do we have excuses to do physical work or just excuses not to work 'hard'? ;-)