People who work shifts may struggle to get enough sleep or get a restful night’s rest, but now a study has found the ideal sleep strategy that could help counteract the drowsiness and fatigue experienced by workers on a night shift. 16 hours, and which could also be beneficial for new parents.
The work analyzed data from pilot studies on napping during night shifts that had been carried out between 2012 and 2018 and observed that, when it is necessary to stay awake all night, scheduling two nap sessions (one of 90 minutes, followed by a sleep quick 30-minute nap later) is the best option for postponing drowsiness and fatigue, compared to a single 120-minute nap.
“A 90-minute nap to maintain long-term performance and a 30-minute nap to maintain lower levels of fatigue and quicker reactions, as a strategic combination of naps, may be valuable for early work efficiency and safety.” morning,” said the study’s sole author, Sanae Oriyama, professor of nursing sciences at the Graduate School of Biomedical and Health Sciences at Hiroshima University, whose findings have been published in Scientific Reports.
Segment your sleep or sleep straight?
In some professional fields, shift work is essential, as is the case with workers who are responsible for solving emergencies or providing health care. And it is not uncommon for these people to have to work double shifts at non-traditional hours. However, it is known that working night shifts increases the risk of developing sleep-related physical and psychological health problems and negatively affects work performance.
“The results of this study can be applied not only to night shift workers, but also to minimize fatigue due to lack of sleep in mothers raising their children.”
Our internal clocks or circadian rhythms are responsible for regulating wakefulness and sleep and light influences them, so during the day we are predisposed to activity and, at night, to rest, so during the hours of darkness we have more likely to make mistakes and cause accidents, something that, in the case of healthcare professionals, can lead to harm to patients, and therefore these shift workers often take naps to compensate for alterations in the biological clock.
In Japan, for example, nurses are often allowed to sleep up to two hours during 16-hour night shifts, and Oriyama wanted to find out which nap schedule is best to combat drowsiness and decreased cognitive function during such grueling workdays. .
Oriyama reexamined previous pilot studies she had co-authored to compare alertness and cognitive performance after taking a nap and during a simulated 4 p.m. to 9 a.m. shift. The one-nap experiment was conducted in 2012, the two-nap experiment in 2014, and the no-nap experiment in 2018. “I want to be able to combine several naps, depending on the type of work and the time of day.” day, and choose naps that are effective in reducing drowsiness, fatigue and maintaining performance,” explained the researcher.
He found that those who took a single 120-minute nap that ended at midnight experienced worse sleepiness at 4 a.m. that lasted until the end of the shift. However, participants who scheduled two naps (the 90-minute one that lasted until midnight and the 30-minute one that ended at 3 a.m.) avoided drowsiness until 6 a.m. Oriyama suggested adding an extra 30 minutes of sleep between 5 and 6 a.m. because sleepiness could increase between 7 and 8 a.m.
Regarding fatigue, although participants in all nap groups reported significantly higher levels between 4 and 9 a.m., the two-nap group experienced it with a lower intensity than the others.
Find the best time to take a nap and the ideal duration
The new study involved 41 women in their 20s who were invited to a soundproof, windowless laboratory for a simulation of a 16-hour night shift. The room temperature was maintained at 26°C and the light intensity was similar to the lighting level in the offices. Their temperature, levels of sleepiness and fatigue, heart rate and blood pressure were measured. After the tests, the participants had free time to do whatever they wanted at their desks. During their scheduled nap time they moved to a neighboring room where they were allowed to dim the light according to their preferences. During this time their sleep parameters were measured.
Both single and split naps did not result in improved performance on cognitive tasks. However, Oriyama noted that those who took longer to fall asleep during the 90-minute nap session scored worse on the Uchida-Kraepelin Test (UKT), a timed basic math test meant to measure speed and accuracy in the completion of a task.
It takes 90 minutes to complete a full sleep cycle, and waking up before it ends could intensify the sleep inertia, grogginess, and disorientation experienced when first waking up. The study also found that if total sleep time is prolonged fatigue and sleepiness could also increase, while previous research showed that a nap of 30 minutes or less could help increase alertness, alertness and levels of sleep. energy.
The study also revealed that the timing of the nap plays a key role: the later you take it, the more powerful it will be in defending you from drowsiness and exhaustion. However, delaying it too long could interfere with concentration as the desire to sleep increases. “Therefore, there is a need to better clarify the ideal time to take a nap and the ideal time to nap during long night shifts,” Oriyama said.
Oriyama concludes that her findings could also be useful for people who have recently had a baby: “The results of this study can be applied not only to night shift workers, but also to minimize fatigue due to lack of sleep in women. mothers raising their children.”
