Study finds broken sleep takes a toll
New parents, on-call workers confused, cranky
It will come as no surprise to new parents struggling after a night of feeds, or to doctors on call, but being woken up briefly during an otherwise normal night of sleep is as detrimental as sleeping for just four hours.
Researchers discovered that being woken from a deep slumber by a crying baby or an emergency call, causes the same confusion, depression and fatigue as being severely sleep-deprived.
It means that even when people get a total of seven hours sleep a night, having that sleep regularly interrupted will leave them feeling as if they have slept for barely half that time.
Researchers at Tel Aviv University warned that such interruptions were likely to leave parents feeling bewildered, dejected and exhausted and could have a detrimental effect on on-call professionals, including doctors or firemen, impacting upon their at- tention span and ability to make decisions.
“The sleep of many parents is often disrupted by external sources such as a crying baby demanding care during the night,” said Prof. Avi Sadeh.
“Doctors on call, who may receive several phone calls a night, also experience disruptions. These night awakenings could be relatively short — only five to 10 minutes — but they disrupt the natural sleep rhythm..”
The team studied 61 adults who were monitored at home using wristwatch-like devices that detected when they were asleep and awake.
The volunteers slept a normal eight-hour night, then experienced a night in which they were woken four times by phone calls every 90 minutes and not allowed to go back to sleep for 15 minutes. The students were asked each following morning to complete computer tasks to assess alertness and attention, as well as to fill out questionnaires to determine their mood.
The experiment showed a direct link between disrupted sleep and poor attention spans and negative mood after only one night of frequent interruptions.
The volunteers were found, on average, to be 24-per-cent more confused, 29-per-cent more depressed and 43-per-cent more fatigued after broken sleep.
A second experiment in which volunteers were allowed to sleep for only four hours, showed similar results, suggesting regular night disruption has the same impact as getting only half the recommended eight hours of sleep.
“We know that these effects accumulate and therefore the functional price new parents — who awaken three to 10 times a night for months on end — pay for common infant sleep disturbance is enormous.
“Besides the physical effects of interrupted sleep, parents often develop feelings of anger toward their infants and then feel guilty about these negative feelings.”
The team hopes the findings will encourage employers to reassess shift work and staff being placed on call.