Simple exercise is sometimes extremely effective if done consistently enough. Besides--it's a method similar to weight training. You could do just as much damage to yourself exceeding your normal weight limit.

In this capacity, it's the same as adding weights to your ankles and wrists.

[He was aiming more for gains in stamina--since bulky muscle wasn't really anything he wanted.]

I'm fairly certain it's only easy in terms of planning. It's not going to be enjoyable at all for me.