Search Here

People are generally not happy if their sleep gets interrupted.

In a new study, researchers at John Hopkins University School of Medicine set out to examine how sleep can affect mood. The team recruited 62 adults with healthy sleepy patterns. They were randomly assigned to one of three sleeping conditions in the experiment, which were forced awakenings, delayed bedtimes or uninterrupted sleep (control). The experiment took place at an inpatient clinical center for three consecutive nights.

The researchers found that people who experienced eight forced awakenings and those who had delayed bedtimes were more likely to be in a low positive mood and a high negative mood after the first day. Mood was measured using a questionnaire.

By the second night, the team found that the people who had forced awakenings experienced a 31 percent drop in their positive mood. The delayed bedtime group had a 12 percent decline in their positive mood. By the final day, there was no difference between the moods in the forced awakening and delayed bedtime groups.

When the researchers looked at brain pattern, they found that people from the two experimental groups and not the control group had less slow wave sleep, also known as deep sleep. Deep sleep is tied to feeling rested.

"When your sleep is disrupted throughout the night, you don't have the opportunity to progress through the sleep stages to get the amount of slow-wave sleep that is key to the feeling of restoration," says study lead author Patrick Finan, Ph.D., an assistant professor of psychiatry and behavioral sciences at the Johns Hopkins. "We saw a drop in slow wave sleep so large and sudden, and it was associated with a striking drop in positive mood that was significantly different than in the other group."

The researchers noted that the study's findings could be helpful for people with insomnia, people with on-call jobs and new parents.

The study was published in the journal, Sleep.