Adults of Chennai belonging to low-income families sleep, on an average, only five-and-a-half hours at night despite spending eight hours in bed, according to a study that covered a less studied feature of the lives of the urban poor — sleep.
Categorising the finding as “significantly below both time in bed and the recommended [duration of sleep of] 7 to 9 hours,” the study, which was held during October 2017-September 2020, stated that 95% of persons surveyed slept less than seven hours per night and 71% slept less than six hours per night. Though they spent about eight hours per night in bed, their sleep was “highly disrupted,” with 31 “awakenings” (meaning a disruption lasting at least 30 seconds) in a typical night.
The study was carried out as part of the State government’s memorandum of understanding with the Abdul Latif Jameel – Poverty Action Lab (J-PAL) of the Massachusetts Institute of Technology (MIT), U.S., using state-of-the-art objective measurements.
Naturally, sleep efficiency — sleep per time in bed — was 70%, which was far below the minimum of 85%, as stipulated by sleep scientists, for “high quality” sleep.
It was similar to those suffering from disorders such as sleep apnea or insomnia in high-income countries. Among the factors that interfered with the participants’ sleep were environmental conditions such as mosquitoes, noise and heat, and mental and physical distress such as stress, pain and hunger.
Dwelling upon the importance of the theme, researchers concluded that “severe sleep deprivation may have serious long-run effects on health and well-being [of people], and calls for policymakers’ and researchers’ attention. More systematic research on sleep in developing countries is needed to establish the external validity of our findings and to study longer-term effects.”
The study had two samples — 452 residents in one and 3,833 individuals across randomly-sampled neighbourhoods in the city. Its report was published a few months ago.
Drawn from the field of economics, the team of researchers comprised Gautam Rao and Frank Schilbach, Associate Professors of Harvard University and MIT respectively; Heather Schofield, Assistant Professor, University of Pennsylvania; Pedro Bessone Tepedino of the MIT and Mattie Toma of the Harvard.
Most of the persons surveyed were unemployed and those who earned more than ₹15,000 a month in their current or previous job were excluded from the study.
A few other criteria were also taken into account to determine that the participants in the study belonged to low income families.
In respect of the smaller sample, the randomised controlled trials (RCT) were done. The persons covered under the broader sample wore, for three nights, actigraph, a wristwatch-like device that reads sleep/wake data from body movement.