8 Surprise Reasons You're Still Tired

You've Let Yourself Go

Several recent studies have shown a link between obesity and daytime sleepiness, causing researchers to conclude that being overweight is one of the main risk factors for fatigue. The good news is that when the scientists followed up with some of the sleep-study participants seven and a half years later, those who lost weight also reported feeling better rested and more alert.

Next: What the sleep experts do to get a good night's rest