Smartphones disrupt sleep, productivity

Smartphones have been shown to be disruptive of nightly sleep patterns, and new research suggests phone use at night can lead to negative effects the following day, as well.

According to two studies to be published in the journal Organizational Behavior and Human Decision Processes, using a smartphone to fit extra work in at night results in decreased production the following day. Surveying a range of U.S. workers, Michigan State University professor Russell Johnson and colleagues found that people who monitored their phones for business purposes after 9 p.m. were more tired and less engaged upon returning to work.

The physical effects of phone use at night have been investigated: exposure to LEDs (light-emitting diodes) from mobile devices can interfere with melatonin, the hormone that regulates the sleep-wake cycle. But these new studies provide insight into how harmful the effects of mental engagement with smartphones can be. Across both studies, the surveys showed that nighttime smartphone usage for business purposes cut into sleep and sapped workers’ energy the next day in the office.

“The nighttime use of smartphones appears to have both psychological and physiological effects on people’s ability to sleep and on sleep’s essential recovery functions,” said Johnson, an MSU assistant professor of management, in a statement. “Because they keep us mentally engaged late into the evening, they make it hard to detach from work so we can relax and fall asleep.”

In fact, the study results indicated that smartphones had even stronger negative effects than other devices such as laptops or televisions.

While smartphones can be a valuable tool in today’s professional world, the benefits of a constant connection to work can eventually reach a limit.

“There may be times in which putting off work until the next day would have disastrous consequences and using your smartphone is well worth the negative effects on less important tasks the next day,” Johnson said. “But on many other nights, more sleep may be your best bet.”