What does "Sweating like a Pig" mean?

I like scratching around and looking for the origins of sayings and phrases that one hears and uses. Two of these popped up while I was reading stuff on other sites recently.
The first one was “sweating like a pig”. This is an interesting one, as pigs don’t sweat. They have no sweat glands so it is impossible for them to sweat. Then why sweating like a pig? Exactly that, no sweat. If someone is referred to as sweating like a pig it means he is doing absolutely nothing. For example, Hubby is in the garage, supposedly doing something of substance, but he is drinking beer and playing cards with his buddies. This could be referred to as “ He is working in the garage, sweating like a pig”.


The other one was “hell for leather”. Different interpretations on this one. This saying appears to have evolved over the last 100 or so years. Originally “hell bent” meant to be totally committed to doing something at any cost. Rudyard Kipling first documented “Hell for leather” sometime in the late 1800’s while he was in India, and appears to refer to riding a horse very hard.
“Hell bent for leather” originated in 19th Century in America, and referred to an obstinate or troublesome animal such as a horse or cow. The “hell bent for leather” was meant to convey the fact that the animal so difficult to handle that it would have to be slaughtered, and the carcass turned into leather products.