I read this article about sleeping late:
A wise person at work said the evidence in the article didn't support the argument to sleep late, only the argument to awaken naturally. He said it's not waking up early that makes you sick, it's waking up to the external cue of an alarm clock instead of allowing your body to wake up naturally. He recommended playing the sleep game of "Beat the Clock."
Keep an index card by the bed and record when you drop into bed. If the alarm wakes you up, write an X by the time. If you get out of bed before the alarm, write down the time you get out of bed. Not when you wake up, when you get out of bed. The next night go to bed five minutes earlier. He said keeping the time adjustments small is important. Repeat until you get out of bed before the alarm, and keep recording and adjusting your "drop time" until you naturally wake up right before the alarm, like this for someone who sets the alarm to 6:30am:
Before long you won't need to write anything down, because you'll remember if the alarm woke you up, you'll know when to go to bed, and you'll be getting exactly as much sleep as your body wants by playing "beat the clock." This method gives you the health benefits of sleeping late without sleeping late. He says this works even when you can't go to bed at the same time every night, because when you make up the sleep the next night you get a strong sense of how early you can drop without lying awake in bed or getting up too early. He saves a lot of time because eventually you spend virtually no time in bed waiting to go to sleep.
I'm gonna try it. Watch this space.