Smartphone use during night zaps workers' energy

A new research has suggested that using a smartphone to do more work at night results in less work the next day.

In a pair of studies surveying a broad spectrum of U.S. workers, Russell Johnson and colleagues found that people who monitored their smart phones for business purposes after 9 p.m. were more tired and were less engaged the following day on the job.

Russell Johnson, Michigan State University assistant professor of management, said that smartphones are almost perfectly designed to disrupt sleep, as they keep us mentally engaged late into the evening, and make it hard to detach from work so that we can relax and fall asleep.

For the first study, the researchers had 82 upper-level managers complete multiple surveys every day for two weeks. The second study surveyed 161 employees daily in a variety of occupations - from nursing to manufacturing and from accounting to dentistry.

cross 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 second study also compared smartphone usage to other electronic devices and found that smartphones had a larger negative effect than watching television and using laptop and tablet computers.

The study is set to be published in the research journal Organizational Behavior and Human Decision Processes.