(Picture from the blog Shadowwar, written by a fire protection designer and avid video gamer named Andrew, who still has all his hair.)
The takeaway is that as we age, we need less sleep. In your 20s eight hours on the pillow will yield over seven hours of good sleep. By retirement this is down to six-and-one-half hours. Moreover, the oldsters are less tired during the day than the young folks.
We have been running this experiment for a few years at my house, and the results make good sense. My eyes lead me to my pillow before my wife, who wakes for work ahead of me. But while I'll toss-and-turn a long time after I come to bed, she is lights out within minutes, and stays that way until the alarm goes off.
I had credited this to metabolism, but it turns out she's doing things right. When it's bedtime, go to sleep. If you're not sleepy stay up.
Although this also leads to some fun speculation. Since college kids need more sleep than their elders, and get more drowsy during the day, why aren't they doing the early bird dinners and leaving the discos to us at night? Maybe they really are slumbering during those slumber parties.
Anyway, a bit of harmless fun for Groundhog Day.