How Much Sleep Do You Really Need?

Most-emailed article on the Time Magazine site (as of a few days ago):

How Much Sleep Do You Really Need?

As a longtime imsomniac who is always trying to get more sleep, I am a bit skeptical of these claims:

Studies show that people who sleep between 6.5 hr. and 7.5 hr. a night, as they report, live the longest. And people who sleep 8 hr. or more, or less than 6.5 hr., they don’t live quite as long. There is just as much risk associated with sleeping too long as with sleeping too short. The big surprise is that long sleep seems to start at 8 hr. Sleeping 8.5 hr. might really be a little worse than sleeping 5 hr.

Just to state the obvious, maybe the healthy long-life people just need less sleep to begin with. It would seem that there is no way to know if the 7 hours of sleeping a night were a cause or an effect of the good health.

I have weird sleep issues. My insomnia began in graduate school. I walk and talk and do odd things in my sleep. When I was trying to revise my dissertation I would sometimes get up convinced that someone was stealing my laptop, and several times in the middle of the night I arose to hide it in my sock drawer. I quite often run downstairs and check doors and windows, and check (this is a recent favorite) to see if anyone has stolen my bike. In my half-dreaming state I seem to be in some fairy-tale reality full of thieves and “robbers” (a word I believe I’ve used in my sleep-talking) and dangerously permeable borders to a hostile outside world. Recently I’ve sort of been coming to terms with the painful insight that even my late-morning coffee may be affecting my evening sleep. Now I try to avoid any caffeine after about 10:30 a.m. — maybe a decaf at lunch. And a lot of peppermint tea which seems to have some kind of habitual placebo effect.