Johnson attributed the negative impacts to continual work engagement at a time when one should relax and prepare for bed. He said detaching from work before bed is imperative, otherwise added stress can delay sleep onset and reduce sleep quality.

“(The subjects) were more fatigued and drained and less ready for the work day after not receiving the necessary downtime,” Johnson said.

Education sophomore Nicole Bush said she rarely uses her smartphone at night for schoolwork, but does notice a delay in sleep onset after texting friends.

“I think about things that happened, relating to my phone, like people I talked to,” Bush said.

Increased technology usage among associates is what sparked the two studies, said Klodiana Lanaj, an assistant professor at the University of Florida and one of the researchers working on the studies.

“All of us had friends who were tethered to their smart phones constantly,” Lanaj said. “We were interested in how it impacted work the next day.”

Late-night use of smartphones, work-related or not, can produce negative physiological side effects.

Johnson said smartphone backlighting interferes with the production of melatonin, a chemical that regulates falling asleep and staying asleep.

“Exposure to any sort of light when preparing to sleep is bad,” Johnson said. “Blue-light inhibits production of melatonin.”

When late-night smartphone use continually disrupts sleep quality and quantity, the negative impacts can extend past the next day, MSU Counseling Center Director Scott Becker said.

“Over time, this can lead to problems with attention, memory, mood and stress levels,” Becker said in an email. “These changes can be subtle initially, and it is not usually obvious to most people that their technology usage is connected to their sleep or mental health issues.”