36 hours awake/12 hours asleep

So my buddy has been doing a sleep schedule of 36 hours awake and 12 hours asleep, I know generally odd sleep schedules like this have a tendency to be bad for the body, however, I was wondering if this has any negative repercussions. If so, what would it actually do to the body?

Thanks in advance.

Polyphasic sleep is interesting, I've always wanted to try it.  I tired sophmore year of university over spring break. Ended up pussing out and sleeping for 24 hours straight :(