Sanchin and conditioning

We perform kata Sanchin at least once per class, I find it quite exhausting at times, but do notice the work out and benifits it is giving me.

Does it ever get easier to do? Or is it always exhausting as your pushing yourself with the 'go-ju' which to me seems a lot like Charles Atlas's dynamic tension.

I really like it, but after a hard day at work.......:)