GETTING MORE SLEEP HAS SIGNIFICANT benefits. You already know this subjectively; get a good night’s sleep, and you will likely have more energy, emotional control, and a better sense of well-being.

However, a new study from economists at the Massachusetts Institute of Technology (USA) reminds us that we may be thinking about sleep too simplistically. Sleep volume, by itself, does not appear sufficient to yield these health benefits.

Let’s explore this exciting field experiment of low-income workers in Chennai (India). Researchers examined outcomes associated with increasing study participants’ sleep by half an hour per night.

Sleep: Increasing quantity

The MIT researchers studied low-income residents at home and intervened to increase participants’ sleep by approximately 30 minutes per night.

Let’s back up a bit, as I want to provide some context. Low-income adults in Chennai sleep only 5.5 hours per night on average. This low amount of sleep is despite individuals spending as much as eight hours in bed.

The residents’ sleep is highly interrupted; sleep efficiency — sleep per time in bed — is similar to someone with a sleep disorder such as sleep apnea.

Researchers provided each subject with a data-entry job with flexible hours. This assignment allowed the investigators to monitor the effects of sleep on worker output and earnings.

Some members of each group took daytime naps, as the researchers wanted to understand the effects of napping better.

Each subject was given data-entry jobs with flexible hours. This allowed the investigators to monitor the effects of sleep on worker output and earnings.

Sleeping more: Study results

Publishing in The Quarterly Journal of Economics, the economists reported some surprising results:

Sleeping more at night did not improve work productivity, financial choices, earnings, sense of well-being, or blood pressure. The only upside seemed to be that the participants worked fewer hours.

An interesting result: Short naptime naps appeared to improve productivity and well-being.

The researchers note that the participants tended to sleep at night in challenging circumstances, with numerous interruptions. This observation leaves open the possibility that helping people sleep more soundly (rather than simply increasing the total volume of low-quality sleep) might be helpful.

I am not sure we would sleep well if four or five others were sleeping in the same hot and noisy room. The mosquitos can’t help.

The Chennai study subjects increased their sleep from 5.5 hours pre-study, adding an average of 27 minutes of sleep per night. To get those extra hours of sleep, each subject was in bed for an extra 338 minutes. The subjects awoke an average of 31 times per night.

During their data-entry job hours, those who took naps did better in several outcomes, including cognitive function, productivity, psychological well-being, and productivity.

The increased productivity did not translate to higher overall earnings, as the workers did not stay later at work (to make up for the nap time).

Sleep: My take

I would like to see researchers change the sleep circumstances of workers to see the impact of sleep quality (and not only increased quantity) on productivity and other measures.

Devices such as smartwatches should facilitate learning about people’s sleep patterns in their natural home environments. I hope there is an increasing focus on the value of adequate sleep in health and economic outcomes.

Thank you for joining me today.