[Haskell] Monadic Loops

Hi, I've implemented a Neural Net simulator which needs to repeat a training loop many times. For this I used a while function: while test body = do (cond,res) <- body if (test cond) then do rs <- while test body return (res:rs) else return [res] However, when I run the program, the interpreter falls over after a few thousand iterations, running out of space. I think that this is because the Monadic implementation of the while loop actually nests functions of type (a -> M b) and there is a maximum ?stack size. Is there a better way to implement (possibly infinite) loops in Haskell?