A Secret To More Happiness And Energy? Give Yourself A Bedtime.

As a result of my happiness project, I've become a sleep zealot. It's just so obvious to me—from reading the research and from personal experience—that getting enough sleep is a key to a happier life.
I've noticed something, however. I noticed this in myself, before I became such a sleep nut, and I see it in the people around me: most adults don't give themselves a bedtime.
Children have a fixed bedtime; we know they need their allotment of sleep, and we pack them off to bed when it's time. But many adults just go to bed whenever they feel like it.
The problem with this approach is that it's far too easy to stay up too late. The TV, the internet, your email, your book...these distractions keep you alert past the point at which you should head to bed. Many of us know we ought to go to sleep sooner, but we just can't manage to pull it off.
One suggestion: Give yourself a bedtime. Even if you don't actually go to bed on time, at the very least, you should know that you're "staying up past your bedtime." Just the realization that it's an hour past your "bedtime" might help you nudge yourself into bed. Most adults should get 7-8 hours of sleep each night, so do the math.
I get up at 6:00 am, which means my bedtime is 10:30 pm. When I first gave myself a bedtime, I was in the habit of going to bed around 11:30 or midnight. I thought that was an appropriate grown-up bedtime. Well, it's not if you're a grown-up who gets up at 6:00!
For me, at least, getting more sleep was a habit that was self-reinforcing. I felt so, so much better when I started getting enough sleep that it was very easy to observe that bedtime, even though I do regret the loss of those leisure hours.
How do you know if you're not getting enough sleep? Some warning signs:

• you're jolted out of sleep by your alarm clock every morning
• you fall asleep any time you find yourself in a quiet, still place (in a movie theater, or rocking your child)
• you sleep-binge on the weekends
• you feel exhausted all the time
• on the day when Daylights Savings Time gives you an extra hour of sleep, you feel amazing

Try it. Don't even attempt to go to bed earlier. Just identify your bedtime. We tend to manage what we measure, and by identifying a specific bedtime, you might find yourself developing the habit of turning off the light earlier.
Do you have a regular bedtime, or not? If so, how much sleep do you get, and when do you turn off the light?