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Late-Afternoon Coffee
Scientists at the Sleep Disorders & Research Center at Henry Ford Hospital in Detroit found that consuming 400 milligrams of caffeine (equal to two to four eight-ounce cups of brewed coffee) six hours before bedtime reduced sleep by more than an hour.

The Fix: Finish your java by 5 P.M. or earlier.
screen time

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Screen Time in Bed
The light that gadgets emit can suppress the sleep-inducing hormone melatonin.

The Fix: Dim the brightness of your device to its minimum and hold it at least 14 inches from your face. A Mayo Clinic study found that these two moves can cut light exposure to the point that it shouldn't interfere with your sleep.

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Dinner Near Bedtime
When you go to bed with a full stomach, your gut is turning on hormones and stimulating the body when it should be getting ready for rest.

The Fix: Eat your last meal three to four hours before you plan to sleep.

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Not only do smokers appear to spend less time in deep sleep than nonsmokers, but in one recent study, their total sleep time fell by 1.2 minutes per cigarette smoked.

The Fix: Just quit, already!

Read more: 14 reasons you still can't sleep