I'm not sure if I agree Henry, as tadeas said, when you are sick you need more sleep, so it would be more useful to let your body sleep overtime if it has too.
I personally have always used a freerunning sleep. Though somedays when i need to wake up early to get somewhere, I set a quiet alarm about 7 hours after I go to sleep (and make sure i go to sleep early enough so I can wake up on time) which then wakes me after 5 full cycles of sleep, waking me when I'm in a light sleeping stage, which always ensures that I wake up refrshed and not groggy as you would when waking from deep sleep. |