I am a recently graduated PhD, but for the past few years I have been on an 8:00-16:30 schedule with a lunch break at noon. I arrive between 7:45-8:00 and get started immediately.
Now I am on as a continuing research scientist and have been assigned to supervise two graduate students and another post-doc that's new to the field. It's important for our schedules to overlap, so I've instructed them to meet me at 8:00 to get started.
To clarify the frequency, this type of "meeting" would be once a week for the next 13 weeks. I use quotes because it's really just the time we agree to get in the lab and start work together, which is still a meeting but not the one we often think of when we see the word.
Someone I am close to, who has both graduate school and office (industry) experience, tells me this is unreasonable. According to her, even in formal business environments, the first [half-]hour is reserved for checking your email, getting settled, going through voicemails, etc.
As I like to tell people, I was a student for 25 consecutive years, so I know the ropes regarding when academics typically wake up and get started. I'm not asking if starting work at 8:00 AM is typical, but rather if it is unreasonable and why I should or shouldn't change my policy.