Imagine someone wants to go to sleep at midnight and wake up at 7.30 am, so that they get an ideal five sleep cycles (7 1/2 hours).
First scenario: they go to bed at 11.30 and fall asleep within 15 mins, so they get 7 hours 45 minutes of sleep. Their alarm will probably wake them up at the beginning of a new sleep cycle.
Second scenario: they go to bed at 11.30 but can't sleep, and toss and turn for 45 mins, so they get about 7 hours and 15 minutes of sleep. Their alarm probably went off towards the end of their last sleep cycle.
The question is: which scenario could be more detrimental to one's health in the long term? Would it impact your sleep health more to wake up at the beginning of a new sleep cycle, or towards the end of the last one?