Sleep interruptions apparently do worse for the mood than having fewer hours of sleep.
A new research by a team from the Johns Hopkins Medicine found that rude awakenings in the middle of sleep is detrimental for people's health and moods, according to their findings published on the Sleep journal.
"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," study lead author and assistant professor Patrick Finan from the Johns Hopkins University School of Medicine explained.
For the experiment, the researchers had 62 men and women subjected to random sleeping conditions for three nights: one wherein they were subjected to forced sleep interruptions, one where they had delayed bedtimes or one where they slept fully at regular sleeping hours.
The participants were then given standard mood assessment questionnaires every night before sleep to measure how they felt after each night based on the quality of sleep they had.
Participants who had to experience forced awakenings and delayed bedtimes reported lower positive and stronger negative moods the first night. However, come the second night, the group who had to endure forced awakenings had a reduction of their positive moods by 31 percent, while those who had delayed bedtimes only declined by 12. There was no significant difference between the two groups when it comes to their negative moods.
Based on these findings, Finan concluded that several instances of interrupted sleep could possibly have a cumulative sort effect on a person's positive mood, since the differences in positive mood among the groups became clearer after the second night and continued to the next.
Researchers also found that people who were part of the frequently interrupted sleep group had shorter periods of deep, slow-wave sleep. A reduction of these periods was found to be associated with reduced positive moods. The participants from this group were also found to have reduced energy levels and had less capacity to feel empathy or friendliness to others.
"You can imagine the hard time people with chronic sleep disorders have after repeatedly not reaching deep sleep," Finan said.