Getting enough sleep is about more than the number of hours you are in bed.
Johns Hopkins University School of Medicine has found that people forced to waken multiple times during the night showed a greater decline in positive mood than those forced to go to bed later. The study, published in the journal Sleep showed those whose sleep was interrupted multiple times to go to the bathroom or tend a baby also had less deep sleep, the third stage of non-rapid eye movement sleep.
One study done in Israel and published last year, found that a fragmented night of sleep for a full eight hours impacted mood and attention as much as sleeping just four hours a night.
In the Johns Hopkins study, healthy people without any diagnosed sleep problems were given eight hours to sleep in the lab for three consecutive days.
Another healthy group, whose sleep was disrupted, was awakened each hour for seven or eight hours. A third group slept just four hours. Both of these groups' moods dropped after the first night, and those in the forced-awakening group continued to show a decline in mood.
Those in the four-hour sleep group saw their moods stabilize over the three days.
The researchers conclude that consolidated sleep, even if shorter than one's accustomed to, is less detrimental to positive mood than disrupted sleep.
