A study led by Johns Hopkins Medicine researchers suggests that awakening several times throughout the night is more detrimental to people’s positive moods than getting the same shortened amount of sleep without interruption.
As they report in the November 1 issue of the journal Sleep, researchers studied 62 healthy men and women randomly subjected to three sleep experimental conditions in an inpatient clinical research suite: three consecutive nights of either forced awakenings, delayed bedtimes or uninterrupted sleep.
Participants subjected to eight forced awakenings and those with delayed bedtimes showed similar low positive mood and high negative mood after the first night, as measured by a standard mood assessment questionnaire administered before bedtimes. Participants were asked to rate how strongly they felt a variety of positive and negative emotions, such as cheerfulness or anger.
But the researchers say significant differences emerged after the second night: The forced awakening group had a reduction of 31 percent in positive mood, while the delayed bedtime group had a decline of 12 percent compared to the first day. Researchers add they did not find significant differences in negative mood between the two groups on any of the three days, which suggests that sleep fragmentation is especially detrimental to positive mood.
“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.”
Source: Science Daily