In the first of its kind study, researchers from Tel Aviv University's School of Psychological Sciences examined the similarities between interrupted sleep and no sleep, as well as the effect of cognitive abilities when one is deprived of sleep.

The study comprised of 61 student volunteers at the university and the researchers monitored their sleep patterns through the use of a wristwatch-like device that was able to detect when the person was asleep or awake. The participants experienced a normal night with eight hours of sleep and then another where they were awakened four times by phone calls. After each phone call they were asked to complete a short computer task before going back to sleep, forcing them to experience 10-15 minutes of wakefulness.

The following morning the subjects were assigned questionnaires that would help the researchers determine their mood, and after only one night of interruptions, the experiment revealed a direct link between compromised attention, negative mood, and disrupted sleep. They also found that a night of interrupted sleep is equivalent to no more than four consecutive hours of sleep, acknowledging that parents with babies are those who suffer the most.

"These night wakings could be relatively short -- only five to ten minutes -- but they disrupt the natural sleep rhythm. The impact of such night wakings on an individual's daytime alertness, mood, and cognitive abilities had never been studied. Our study is the first to demonstrate seriously deleterious cognitive and emotional effects," said lead researcher Professor Avi Sadeh in this Science Daily news release.

The study, "Effects of One Night of Induced Night-Wakings Versus Sleep Restriction on Sustained Attention and Mood: A Pilot Study," was published in the journal Sleep Medicine. Professor Sadeh is currently conducting research on interventions for infant sleep disturbances to potentially help reduce the negative effects of disrupted sleep on parents in the future. Among being woken up in the middle of the night, other factors affect one's sleep cycle including nightmares, REM behavior disorder, sleepwalking, and circadian rhythm sleep disorders.

The National Sleep Foundation notes that the amount of required sleep varies between people of different ages and those with different needs, but it's most important to get an uninterrupted night's sleep to ensure optimal performance on a daily basis.

You can read more about the study in this Tel Aviv University news release.