Sleeping is the least energy-intensive activity. It's also good for you. (iStock)
We all know sleep matters for job performance. After a week of vacation, you may find your work better than ever. But rack up a week of sleepless nights — say, following a polarizing presidential election — and you may find yourself struggling.
It wouldn't surprise anyone that sleep affects attention, memory and cognition — important factors in the workplace. But striking new research suggests the effect of additional sleep has a high monetary value. A paper— from Matthew Gibson of Williams College and Jeffrey Shrader of the University of California at San Diego, based on data from Jawbone, the fitness- and sleep-tracker company — says that additional time sleeping can translate into thousands of dollars in wages.
Now, the story is not so simple. Don't think you can start to sleep more and you will instantly make more money. It's more about the subtle interplay between how people schedule their lives, how much time they have available to sleep and how that affects worker performance and, ultimately, earnings.
To investigate how sleep affects worker wages, the researchers took advantage of a kind of natural experiment — sunset times across American time zones. Past research shows that people naturally end up sleeping longer when the sun sets earlier, for example in the winter, even if the person goes to bed well after dark. When the sun sets an hour later, it reduces nighttime sleep by roughly 20 minutes per week.
Within a single time zone, the time of sunset varies substantially, as the map below shows. For example, the sun sets about an hour and a half earlier in Mars Hill, Maine, than in Ontonagon, Mich., even though both are in the Eastern time zone. Because there shouldn’t be any significant differences in workers on the eastern or western edge of a time zone beyond the amount of time they sleep, researchers use this variation to calculate how much sleep influences wages.
They find that a one-hour increase in average weekly sleep in a location increases wages by 1.3 percent in the short run, which include changes of less than a year, and 5 percent in the long run. By moving to a location where a sunset is one hour earlier, a worker will make an additional $1,570 a year..