It’s well-established that a lack of sleep can impair cognitive function and lead to adverse physical outcomes. But is it possible that a lack of sleep can also explain social issues, like poverty?

You’ve probably heard the saying, “Work, play, sleep: pick two.”

Unfortunately, as human beings, we cannot do everything.  Turns out, in this constant negotiation, many more people should be picking sleep over work or play.

Researchers have demonstrated that, for most people, sleeping less than six hours a night results in cognitive impairment and a host of other health problems, including increased risk for Type II diabetes and cardiovascular disease. These diseases are also more common among the poor, which leads to some obvious questions: Does poor sleep lead to health problems and lower earnings?  Or is it the other way around- that poor health and lower earnings result in poor sleep?  Can a lack of sleep explain the income gap?

Freakonomics recently published a two-part podcast on the topic of sleep and how it may affect not just health outcomes, but also the financial outcomes for people.  It begins by discussing the puzzle over whether poverty leads to poor sleep (environmental factors, the stress of poverty, or the need to work more than one job may interfere with regular sleep) or whether poor sleep leads to poverty (the impaired cognition that results from insufficient sleep keeps us from earning our full potential).

There is no clear answer but, the podcast takes the listener through a few different data sets and explains the relationship between sleep and overall health, and between overall health and socioeconomic status.
Here are a few of the findings of the Freakonomics bloggers:

  • David Dinges, a professor of psychology and psychiatry at the University of Pennsylvania, explains that lack of sleep undoubtedly leads to weight gain.
  • Lauren Hale, an Associate Professor of Preventive Medicine from Stony Brook, is currently conducting research with a project called the Fragile Families and Child Wellbeing Study and has found that by the age of 5, kids with a regular, language-based bedtime routine (i.e. reading bed-time stories, singing a song) outperform kids without bedtime routines in cognitive tests.
  • Anne-Marie Chang, Chuck Czeisler, and other colleagues of Harvard University published an experimental study in which they kept people in a laboratory at night. The participants were asked to read the same book before going to sleep—half read a paper book and half read the book on an iPad.The iPad readers found it harder to sleep, and once asleep, their sleep was lower in quality.
  • Ten years ago, Jens Bonke, an economist and a senior researcher at the Rockwool Foundation in Copenhagen in Denmark, studied the average earnings of ‘early birds’ and ‘night owls’.He scoured the Danish time-use survey that covers how more than 10,000 people spend for every minute of the day. He found that those who preferred to get up early earned an average of 4-5% more than those who preferred to get up late.
  • Matthew Gibson and Jeffrey Shrader, PhD candidates at the University of California-San Diego studied how much sleep people at opposite sides of the same time zone clocked each night.Most people in the same time zone wake up for work around the same time each day to follow the standard 9-5 work day.However, they are inclined to go to bed at different times because their body clocks follow the sun. The sun sets earlier in the eastern part of a time zone and later in the western part of the time zone, encouraging people in the east to go to bed earlier than those in the west. Gibson and Shrader then compared the incomes of people living in cities on either extreme of the same time zone and found that those on the eastern edge had higher wages than those on the western edge of the time zone. They further state that permanently increasing sleep by an hour per week for everybody in a city, increases the wages in that location by about 4.5%. Taking it one more step, they also found that if you get an extra hour per night, “on average increases wages by 16%, highlighting the importance of restedness to human productivity.”
  • Heather Schofield, a development economist at the Center for Global Development is currently running a randomized control trial in Chennai of about 250 people who are employed in jobs that involve repetitive data tasks. In India, people from lower economic classes face a lot of environmental hazards to a good night of sleep: loud honking from cars and taxis; many families live in one room creating inherent disruptions as people toss and turn; it’s incredibly hot, with average temperatures around 90-95 degrees Fahrenheit round year; many sleep on hard, concrete floors without pillows or mattresses; and mosquitos are very common since it’s a tropical climate.  Half of the study’s participants will be given a mat to sleep on, a pillow, a light sheet, a fan, an eyeshade, and ear plugs. They will also be permitted to take a nap in the study’s office each day for 20-30 minutes if they would like to.  The participants’ work productivity will then be monitored by tracking how many data points they enter, when they enter them, how quickly they do so, and how accurate their work is.  It’s too early to tell what the research will yield, but Schofield predicts that since work is compensated according to how much and how well the data processors work,  those who are given the resources to sleep better will end up earning more as their performance improves.

For more insights, read part 1 here and part 2 here. You can also listen to the podcasts on the Freakonomics website.

While the podcast does not fully answer the question of whether poor sleep results in lower earnings or vice versa, the research is clear: sleep is a natural panacea that can make us healthier, smarter, and happier. The trouble is, it only works if people get enough of it.

This article was first published by The World Bank’s People, Spaces, Deliberation blog. Publication does not imply endorsement of views by the World Economic Forum.

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Author: Roxanne Bauer is a consultant to the World Bank’s External and Corporate Relations, Operational Communications department (ECROC).

Image: Delegates rest during a break of the plenary session at the U.N. Climate Change Conference COP 20 in Lima December 13, 2014. REUTERS/Enrique Castro-Mendivil.