We met on a Monday, his only day off. By Tuesday afternoon, he can hardly wait for Wednesday, when he only works one job. Between the two jobs, he brings home $500 a week.

The tight schedule lends McCalman a heightened awareness of how seemingly minor changes—a missed stop here, a traffic jam there—shave precious minutes off his sleep. “If the buses are messed up, I’m not getting that four hours,” he said. “If I had my own transportation, I might only need an hour to get to work.”

By 2 p.m. each day, McCalman finds himself “literally falling asleep. I’m with a chair, and I’m waiting at the checkpoint, and because I’m waiting, my eyes start closing.”

McCalman’s life reveals a particularly sorry side of America’s sleep-deprived culture. Though we often praise white-collar “superwomen” who “never sleep” and juggle legendary careers with busy families, it’s actually people who have the least money who get the least sleep.

Though Americans across the economic spectrum are sleeping less these days, people in the lowest income quintile, and people who never finished high school, are far more likely to get less than seven hours of shut-eye per night. About half of people in households making less than $30,000 sleep six or fewer hours per night, while only a third of those making $75,000 or more do.

“We all have sleep problems,” McCalman says, speaking of his fellow airport workers. “Everyone who is doing two jobs has a sleep problem.”

* * *

For most of the 1800s, a 12 to 16-hour workday was common. “Coal heavers” in Philadelphia protested in 1835 for the right to work just 10 hours per day. The labor movement, along with paternalistic industrialists like Henry Ford, were essential in normalizing the idea that people should work only eight hours. The chorus of one of the most popular labor songs from the 19th century went like this:

We want to feel the sunshine and we want to smell the flowers

We are sure that God has willed it and we mean to have eight hours;

Eight hours for work, eight hours for rest,

Eight hours for what we will.

But many low-income workers don’t even get an hour for “what they will,” and the eight hours of rest are increasingly hard to come by, too. Working minimum wage for eight hours per day would earn a worker $1,386 per month, less than half of the current median average rent in Brooklyn.

Night workers tend to be disproportionately affected, getting about two to four hours less sleep than normal. Our bodily rhythms are set by sunlight. Exposure to bright light when it’s time to sleep makes it harder for the body to produce melatonin, a sleep hormone. Over time, this sleep deprivation translates to an increased risk for heart disease, gastrointestinal problems, and reproductive issues.