Woke up on the wrong side of the bed? Researchers say that a bad sleep is not only affected by its quantity but also with its quality. It revealed that three successive nights of interrupted sleep could result to bad mood.
According to Patrick Finan, assistant professor of psychiatry and behavioural science at John Hopkins University School of Medicine, disturbed sleep causes more harm than inadequate sleep. The National Sleep Foundation recommends at least 7 to 9 hours of sleep for adults between 18 and 64 years old and 7 to 8 hours for 65 years and older. The organization emphasized that adequate sleep can enhance the immune system and mood.
However, this research deems quantity equally important with quality sleep. "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," Finan said.
To demonstrate its effects, a study with 62 healthy individuals was conducted. Housed in a clinical research suite, participants were randomly divided into three groups. One group had undisturbed sleep, the second group had delayed bedtimes, and the third had eight occurrences of sleep disturbance.
Results were obtained using two methods. First, sleep stages were monitored and recorded via a polysomnography. Second, participants were asked about how they felt after each night.
On their first night, no significant results were found. After the second night, there was a 31 per cent reduction of positive mood in the undisturbed sleep group, while the delayed sleep group experienced a 12 per cent reduction. These reductions continued until the third night. The team concluded no differences in negative mood between the two groups, which mean that the disturbed sleep has more impact on positive mood.
Upon assessing the results obtained, researchers found that interrupted sleep groups have shorter periods of "deep sleep," stage for body repair and maintenance, compared with the delayed sleep group. This may be the reason that 10 per cent of the US population with chronic insomnia ends in depression.
