Afternoon nap in healthy workspace can improve productivity among urban poor workers: Study

A new study that measured sleep quality in real situations in low income groups in Chennai found outcomes to be vastly different from findings of research in sleep labs in the West.

A couple of workers take a nap between work | Representative Image | Commons

New Delhi: A study conducted on low-income families in Chennai has found that increased period of sleep during nights has no significant effect on a person’s productivity.

“Contrary to expert predictions and a large body of sleep research, increased night-time sleep had no detectable effects on cognition, productivity, decision making, or well being, and led to small decreases in labor supply,” stated the study.

Titled The Economic Consequences of Increasing Sleep Among the Urban Poor, the study was published in The Quarterly Journal of Economics on 8 April. The research team comprised five economists, including Pedro Bessone and Frank Schilbach from MIT and Gautam Rao of the Harvard University and the National Bureau of Economic Research, United States.

During the course of their study, the five economists tried to study the average sleep efficiency of individuals from lower-income families residing in Chennai, over a three-week period.

The findings are important since it provides an insight into sleeping patterns and quality of sleep in people from lower-income countries at their homes, as opposed to the findings of most sleep laboratories that are set up in the West.

For example, the study found that adults from low-income backgrounds in Chennai slept for only 5.5 hours in the night on an average, despite spending eight hours in bed. This is because their sleep was highly interrupted, owing to factors like bad weather and poor surroundings. Despite increasing their time in bed, their time of quality sleep only increased by 27 minutes and there was no change in productivity because of the increased sleep time.

In contrast, participants who were given an afternoon nap time of 30 minutes in a healthy workspace showed  an “improved overall index of outcomes by 0.12 standard deviations, with significant increases in productivity, psychological well-being, and cognition, but a decrease in work time.” This, they said, was probably because of the availability of a safe place to sleep.

Measuring sleep

To measure the economic effects of increased sleep, the researchers conducted a random controlled trial with 452 adults in Chennai. “We employed participants for a one-month data entry job with flexible hours, allowing us to precisely measure productivity and labour supply, as well as physical and psychological well-being, cognition, and time, risk, and social preferences”, stated the paper.

Actigraphs — devices that resemble wristwatches and infer sleep/wake states from body movement — were given to all participants to measure their sleep outcomes. The devices allowed researchers to objectively measure sleep in participants’ home environments.

Starting on the ninth day of the study, a random subset of individuals were given the opportunity to take a short afternoon nap every day between 1:30 and 2 pm. Located in a quiet and gender-separated part of the study office, the 25 private nap spaces included a bed, blanket, pillow, table fan, earplugs, and eye shades. The actigraphs showed that roughly 90 per cent of study participants did sleep during their allotted nap time.

While the study found that increased night sleep did not significantly improve physical or psychological well-being, probably because sleep quality continued to remain poor, those who showed marginal increase in productivity, well-being, and cognition, was due to the availability of a safe place to sleep, researchers feel.

In conclusion, the researchers stated in the paper that while sleep quality continues to remain poor across developing countries, that reality may not emerge from studies in a lab.

“The low-quality sleep we discovered in Chennai may not offer the same marginal benefits as the sleep typically available in higher-income settings,” stated the report, adding that findings from a lab study may not even be the general on ground reality even in rich, developed countries.

(Edited by Poulomi Banerjee)