“The evidence that time spent working was the most prominent sleep thief was overwhelming,” said lead author Mathias Basner, assistant professor at the University of Pennsylvania Perelman School of Medicine, in a press release.

The study found that work was the activity most exchanged for sleep on weekdays, weekends, and holidays across all sociodemographic categories. In particular, they saw that short sleepers worked 1.6 hours more on weekdays and 1.9 hours more on weekends and holidays compared with normal sleepers. They also found self-employed workers sleep more than private sector or government employees. Unsurprisingly, they found that workers with multiple jobs were 61 percent more likely to be short sleepers.

In second place for the culprit of decreasing sleep was length of commute—short sleepers tend to have longer commutes to school or work. Americans average 25 minutes of travel to work, but longer commutes for 1.7 million Americans come in at over 90 minutes.

Other habits that people give up sleep for will sound familiar: socializing and sleeplessness at night, and grooming in the morning. Their study ranked watching TV at number nine on the list of activities that are commonly exchanged for sleep.

There are some shortcomings to this study. As the accompanying commentary notes, this study uses time-use survey data—meaning it doesn't take into account sleep-affecting factors such as alcohol, caffeine, medication, or light exposure.

However, as lack of sleep is linked to health problems (obesity, hypertension, and cognitive performance, to name a few) and even car accidents (the study cites that least 83,000 car crashes in the U.S. are due to drowsy driving)—the researchers recommend shorter commutes and that later start times for school and work might help Americans get more sleep. And if those are not options, the small things that can give big gains to our sleep time are socializing less and getting ready faster in the morning. In other words, sleep a little more and don't worry—your hair looks great.

We want to hear what you think about this article. Submit a letter to the editor or write to letters@theatlantic.com.