Are you a night owl   or a morning lark? Most people are one or the other.

According to Dr. Meir Kryger, director of the Sleep Disorders Center at Canada's University of Manitoba, everyone has an internal body clock that sets their sleep cycle. And no matter how hard you try to change it, most people can't fight their biology.
Also, Kryger says we all have a "sleep number"   the optimal number of hours we need to sleep every night. And even though some people boast that they can get by on 4 or 5 hours, they're just fooling themselves. The truth is that most people need 7 to 8 hours of sleep every day to function properly. And when we scrimp on that, that number actually goes up - at least temporarily. Few people can truly adapt to getting less sleep than they need.
So, how can you make sure you get the 7 or 8 hours YOU need? Well, aside from figuring out if you're a night owl or a lark - and respecting that - here are some tips from Web MD: First: If you have a pet, give it a separate bed. Noise and movements during the night can disturb your sleep more than you realize.
Next: Don't nap during the day. It'll make it harder for you to settle down at night.
Also: Keep your bedroom as free from light, noise and temperature extremes as possible. As we get older, we become more sensitive to these things. And you may not realize that sleeping with the radio on or the fan on may now be keeping you up at night - instead of soothing you.
And one last way to sleep better: Don't drink alcohol close to bedtime. As your body clears it from your system, a withdrawal system kicks in, disturbing your sleep.
And know this: If you wake up after 7 or 8 hours and you STILL feel tired, or if you get a creepy, crawly sensation in your legs when you lie down at night   and you have an uncontrollable urge to move them   you could have a sleep disorder. Talk to your doctor so you can get back on the right track.