The more people earn, the less they sleep. In time-use data from countries around the world, full-time male workers in the top income quartile sleep around half an hour less per day than those in the lowest quartile, and whole countries sleep less as they grow richer.
The study, by Cristián Jara of the Universidad de Chile and Francisca Pérez and Rodrigo Wagner of Adolfo Ibáñez University, was published online in Economics & Human Biology on May 12, 2025.
Diaries of a day around the world
The researchers used time-use surveys, in which people record what they do across a 24-hour day. They combined 11 countries from the Multinational Time Use Study, including the United States, the United Kingdom, Germany, Norway, South Korea and South Africa, with national surveys from Chile, Ecuador and Peru to add more lower-income countries.
To avoid confusing sleep with differences in how much people work, they focused on full-time male workers aged 25 to 65, on weekdays, using the most recent survey for each country collected after 2000. Countries ranged from about $9,000 to $60,000 in GDP per capita.
In an earlier version of the paper, average weekday sleep ran from 6.87 hours in Denmark to 8.06 hours in South Africa. In most countries, people slept less than the commonly recommended eight hours.
The rich sleep less, at home and abroad
Within countries, the gap was consistent. In raw averages, workers in the top income quartile slept 7.28 hours and those in the bottom quartile 7.75 hours, a difference of about 0.46 hours. In panel regressions with country fixed effects and controls for age, marital status, working hours and household makeup, the rich slept between 26 and 34 fewer minutes per day, a gap of roughly 6% to 8%.
The pattern was roughly step by step: the poorest slept more than the middle-income group, which slept more than the richest. The gap pointed the same way in the great majority of countries; the two exceptions, Slovenia and the UK, showed differences that were not statistically significant.
Across countries, average sleep fell as GDP per capita rose. The authors note that both the within-country and cross-country results line up with an income elasticity of sleep of about -0.04, meaning a 10% rise in income goes with roughly 0.4% less sleep. That figure is close to estimates from earlier single-country studies in the United States and Canada.
Swapping sleep for a night out
What do richer workers do with the time? The authors found that higher-income individuals spend more time on other leisure, such as social outings and internet use, which they describe as substituting for sleep.
The authors are explicit that they are measuring a pattern, not proving that income causes less sleep. They note that research going the other way, showing better sleep raises productivity, predicts the opposite sign and a much smaller effect, which suggests something else is driving the gap.
They also found that “sleep poverty”, sleeping under six hours a day, affected around 15% of workers in countries as different as the US, Norway, Ecuador and Peru, with Chile and Denmark the highest at about 22%.
Study Details:
- Title: Sleep hours fall as income rises: Macro and micro evidence on sleep inequality around the world
- Authors: Cristián Jara, Francisca Pérez, Rodrigo Wagner
- Journal: Economics & Human Biology
- Publication Date: May 12, 2025
- DOI: 10.1016/j.ehb.2025.101496