IAMTHAT That Ami:
So in my case, if my body doesnt get 8-8.5 a day of sleep, then the whole day is pretty much filled with physical weakness and is a very miserable day, eyes irritated/red, eventual exahustion, etc. The whole family line on both sides of my family pretty much need this 8, or else the day is ruined.
Now believe me, I have plenty of friends who only need 5-6 hours and they function just fine. Well that's not the case for me, though I wish it was.
I could have written this as well: this describes me exactly! and I also start getting a cold. While I've only been on one retreat, I definitely still needed the full amount of sleep, so I just skipped the 4:30-6:30 meditation session. Even so, I was suffering from lack of sleep by the end (10 days).