MIT Sleep Study Reveals Surprising Results

Getting more sleep seems to offer great benefits. (CREDIT: Creative Commons)

Subjectively, more sleep seems to provide great benefits: many people find it gives them more energy, emotional control, and improved well-being. But a new study co-authored by MIT economists complicates that picture, suggesting that more sleep alone isn’t necessarily enough to achieve such attractive improvements.

The study is based on a representative field experiment with low-income workers in Chennai, India, where the researchers studied the inhabitants of the house during their normal daily lives – and were able to increase the participants’ sleep by about half an hour per night, which is very significant. growth. Yet increasing nighttime sleep did not improve people’s productivity, earnings, financial ability, well-being, or even blood pressure. Apparently the only thing they did was cut back on the number of hours they worked.

“To our surprise, these nighttime sleep interventions had no positive effect on any of the outcomes we measured,” says Frank Schielbach, an MIT economist and co-author of a new paper detailing the study results.

It’s not just that: First, researchers have found that short naps help productivity and well-being. Second, the participants tended to sleep through the night under difficult conditions, with numerous breaks. The results leave open the possibility that helping people get better sleep, rather than just increasing their total amount of low-quality sleep, could be beneficial.

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“The sleep quality of people under these circumstances in Chennai is so poor that adding low-quality sleep may not provide the benefits that an additional half hour of sleep would provide if it were of better quality,” Schilbach suggests.

The article “Economic Impact of Increased Sleep Among the Urban Poor” was published in Economics Quarterly. The authors of the article are Pedro Bessone, Ph.D., 21, a recent graduate of the Massachusetts Institute of Technology Department of Economics; Gautam Rao, associate professor of economics at Harvard University; Schilbach, MIT Associate Professor of Economics for Gary Loveman Career Development; Heather Schofield, associate professor at the Perelman School of Medicine and the Wharton School of the University of Pennsylvania; and Matty Thoma, PhD in economics from Harvard University.

Sleep on rickshaws

Schilbach, a development economist, says the study began with another study he and colleagues conducted in settings such as Chennai, in which they noticed that low-income people tended to have difficulty sleeping in addition to to other daily problems. Problems.

An experiment with the working poor in India showed that when it comes to sleep, quality can matter more than quantity. (CREDIT: Creative Commons)

“In Chennai, you can see people sleeping on rickshaws,” says Schilbach, who is also a fellow at MIT’s Abdul Latif Jameel Poverty Action Laboratory (J-PAL). “Often four or five people sleep in one room where it’s loud and noisy, you see people sleeping between stretches of road next to the highway. Even at night it is incredibly hot and there are a lot of mosquitoes. Basically, in Chennai, you can find any potential irritant or adverse sleep factor.”

This figure provides an overview of the timeline and experimental design of the study. (CREDIT: The Quarterly Journal of Economics)

To conduct the study, the researchers equipped Chennai residents with actigraphs, wristwatch-like devices that detect sleep status from body movements, allowing the team to study people in their homes. In many other sleep studies, people observe in a laboratory setting.

During the study, 452 people were examined during the month. Some were given advice and recommendations on how to improve sleep; others received financial incentives to sleep more. Some members of both of these groups also took an afternoon nap to see what effect it would have.

This figure shows the mean of various sleep-related variables for different treatment groups by day in an RCT study. All results are actigraph measures. (CREDIT: The Quarterly Journal of Economics)

Study participants were also given data entry jobs with flexible hours while the experiment was running, so the researchers could track in detail the effects of sleep on workers’ productivity and earnings.

Overall, study participants in Chennai averaged about 5.5 hours of sleep per night before the intervention and added an average of 27 minutes of sleep per night. However, to win those 27 minutes, the participants spent an additional 38 minutes in bed each night. This speaks to the participants’ difficult sleep circumstances, who woke up 31 times per night on average.

“The main thing that catches the eye is that the efficiency of sleep in people is low, that is, their sleep is highly fragmented,” says Schilbach. “They have very few periods when they experience what is considered to be the restorative effect of deep sleep. … The amount of sleep people have increased due to the interventions because they spent more time in bed, but the quality of their sleep has not changed.”

This may be why, on a wide range of measures, study participants did not see positive changes after they began to sleep more. Indeed, as Schilbach notes, “We find one negative effect – the number of hours worked. If you spend more time in bed, then you have less time for other things in your life.”

On the other hand, study participants who were allowed to take a nap during data entry work performed better in several measured categories.

“In contrast to the nighttime sleep intervention, we find clear evidence that daytime sleep improves a number of outcomes, including their productivity, their cognitive functioning and their psychological well-being, as well as some evidence for savings,” says Schilbach. “These two interventions have different effects.”

However, napping only increased overall income compared to workers who took a break instead. Daytime naps did not increase the overall income of workers — nappers were more productive per minute worked, but actually spent less time working.

“It’s not that naps just pay off,” says Schilbach. “In fact, people don’t stay longer in the office when they sleep, presumably because they have other things to do, like taking care of their families. If people sleep for about half an hour, their working time is reduced by almost half an hour, almost by a ratio of one to one, and as a result, the earnings of people in this group are lower.”

Appreciate sleep as an end in itself

Schilbach says he hopes other researchers will look into further questions the study raises. Further work, for example, could try to change the sleep conditions of low-income workers to see if improving the quality of sleep, rather than just increasing the amount of sleep, matters.

Schilbach also suggests that it may be important to better understand the psychological issues that the poor face when it comes to sleep.

“Being poor is very stressful and it can make it difficult for people to sleep,” he notes. “It is worth exploring how environmental and psychological factors influence sleep quality.”

What’s more, with the help of actigraph technology and other devices, Schilbach notes, it should be possible to conduct more studies that record people’s sleep patterns in their normal home environment, and not just in medical settings.

“There isn’t much work on studying people’s sleep in their daily lives,” Schilbach says. “And I really hope that people will study sleep more in developing countries and poor countries, focusing on the results that people appreciate.”

For his part, Schilbach says he is interested in continuing his work on sleep in the US, and not just in India, where he did most of his research. In any setting, he says, we must take sleep seriously as an element of poverty reduction research and public policy, and as an important element of well-being.

“Sleep can be important as a means to increase productivity or other types of choices people make,” Schielbach says. “But I think a good night’s sleep is also important in and of itself. We should appreciate being able to sleep well and not worry at night. Poverty indices are related to income and material consumption. But now that we can better measure sleep, a good night’s sleep should be part of a more comprehensive measurement of people’s well-being. I hope that in the end we will come to this.”

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Note. Materials provided above by the Massachusetts Institute of Technology. Content can be edited for style and length.

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