You might associate stretching with waking up, but it can help you nod off, too.

So if you have trouble falling asleep, trade in the tossing and turning for a simple, gentle, daily stretching routine instead. Women who regularly stretch out their knots and kinks fall asleep more easily than nonstretchers do. Try these easy do-at-your-desk yoga stretches.

Stretching isn't the only exercise factor that affects how well you sleep. Getting regular exercise of any kind can help improve your shut-eye. Just be mindful of the time of day you do it and how long you go at it.

If you prefer to exercise at night, research shows that shorter is better in terms of sleep quality -- evening exercisers get more shut-eye if they work out for no more than 3 hours a week. But finding a different time to be active, if you can swing it, is probably better for your health than cutting back on how much you exercise.

Morning exercisers might need to work out longer to experience sleep benefits -- at least 3 hours and 45 minutes a week. Why isn't clear, but that's no reason to give up on improving your nightlife with a morning walk or jog. Just set that alarm and get yourself into a routine. It won't be long until you're falling out of bed and into your gym shoes before the alarm even goes off.

And for even better sleep, add some gentle stretching to your routine -- it could make all the difference.

Oh, one little alert: Avoid intense exercise within 3 hours of bedtime; revving your system with a hard workout can wake you up just when you're trying to wind down.