If you’re a little short on sleep today, know that more shut-eye might not have changed anything.

A new study from Massachusetts Institute of Technology suggests that more sleep alone doesn’t improve performance or well-being, especially for people whose nighttime sleep is often interrupted.

Most sleep research takes place in labs, where sleep quality is high. Researchers equipped 452 real-world, lower-income workers in Chennai, India, with wrist devices to track their sleep at home. The participants, who worked flexible data entry jobs, then increased their nightly sleep from about 5.5 hours to roughly six hours through a mix of encouragement and financial incentives.

The 30-minute boost did none of the things you would expect. It had no impact on productivity, earnings, decision making, blood pressure, or sense of well-being. This surprised the researchers, because sleep has long been associated with everything from increased energy to emotional control.

MORE