Last week, a 20-something on my staff said 6 hours of sleep a night was enough. I was skeptical. I used to sleep 9 or 10 hours a night in my 20s and 30s.

Those nights are gone. In the last few years, my sleep has been disrupted by breathing problems related to apnea. Sleeping with a CPAP breathing mask has helped, but I am still lucky to get 7 hours of uninterrupted rest. Lately, I have been using a blue light lamp, which seems to increase my alertness and improve my mood in the winter darkness. I also monitor my sleep with an app.