Daylight Saving Time ended on Sunday, and for many of us the extra hour of sleep has provided a small energy boost. It’s widely known that sleep affects our mood and health. Less understood is how it can also affect our paychecks.

A study published last year in the Review of Economics and Statistics found that workers who live in locations where people get more sleep tend to earn more than those in areas where people get less.

One theory: Better-rested workers are more productive and are compensated for it with additional income. “There are other explanations, but we consider them less likely,” said an author of the study, Matthew Gibson, an economist at Williams College.

It’s not as if simply sleeping more will cause your boss to pay you more. In fact, if you get that extra sleep by being late for work, you might earn less or even lose your job. So how would the sleep-income relationship actually work?