Late-night smartphone use has detrimental effects on next-day work productivity

GAINESVILLE, Fla. – Staying up late to work on your smartphone has negative effects on your productivity the next day, a recent University of Florida study shows.

Klodiana Lanaj, an assistant professor of management at the Warrington College of Business Administration, and co-researchers Christopher M. Barnes (University of Washington) and Russell E. Johnson (Michigan State University) found that continuing to work on a smartphone after 9 p.m. increased the likelihood that an employee would be less engaged at work the next day.

“Most employees use their smartphones in bed at night, which is problematic because the “blue light” that smartphones emit interferes with the production of melatonin, a chemical that facilitates falling and staying asleep,” said Lanaj, the lead author of the project. “Using smartphones for work at night also interferes with employees’ ability to detach and recover from work. Ruminating about impending deadlines or work responsibilities consumes cognitive resources leaving employees more depleted in the morning and less engaged at work the following day.”

The researchers conducted two studies. The first study examined 82 mid- to high-level managers, measuring their amount of smartphone use and sleep quality and quantity the previous night, and their level of work engagement the next day. The second study surveyed 161 workers to learn whether the effects of smartphone use on depletion and work engagement were unique from the effects of television, tablet or computer use.

The studies consistently showed that late-night smartphone usage reduced the amount and quality of sleep, increased fatigue the next morning and, consequently, led to diminished work engagement the next day. Smartphone use was more strongly associated with depletion and reduced engagement compared to other electronic devices.

“Smartphones make it more difficult to leave work behind at the office because of their portability and ease of access to email and message notifications. An otherwise pleasant evening, for example, may be disrupted by an email notification from your boss reminding you of that 30-page report due in a week,” Lanaj said.

The study’s findings create a dilemma for managers who provide their employees with smartphones. These workers have the ability to constantly stay connected to their work obligations, but if they overuse this access, it may have a detrimental effect on their productivity when they arrive at work the next morning.

“Although some circumstances may require employees to help clients and coworkers by being accessible late at night, organizations have to recognize the detrimental effects that late night smartphone use may have on employees over the long haul. Prolonged inability to recover from work may lead to exhaustion, reduced productivity, and even health concerns” Lanaj said.

The study, “Beginning the Workday yet Already Depleted? Consequences of Late-Night Smartphone Use and Sleep,” is a forthcoming article that will appear in Organizational Behavior and Human Decision Processes.