Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Sleep strategy used by night nurses throws off their circadian clocks

15.04.2011
As many as 25 percent of hospital nurses go without sleep for up to 24 hours in order to adjust to working on the night shift, which is the least effective strategy for adapting their internal, circadian clocks to a night-time schedule.

That is one of the results of the first study to examine the strategies that night nurses use to adjust between day and night sleep cycles. The study was based on questionnaires from 388 nurses who work at the Vanderbilt University Medical Center and the results are published in the April 13 issue of the scientific journal, Public Library of Science One.

The study also found that variations in individuals’ circadian clock genes have a discernable impact on the nurses’ ability to adapt.

Disruptions to circadian rhythm unhealthy
A number of previous studies have found that repeated incidence of circadian misalignment – the condition that occurs when individuals’ sleep/wake patterns are out of sync with their biological clocks – is not healthy. Jet lag is the most familiar example of this condition. Circadian misalignment has been associated with increased risk of developing cardiovascular, metabolic and gastrointestinal disorders, some types of cancer and several mental disorders.

The way that nursing shifts have been scheduled since the nurse shortages of the 1980’s makes nurses particularly susceptible to this problem. Hospital nurses who work with inpatients do so almost exclusively in 12-hour shifts. The day shift normally runs from 7 a.m. to 7 p.m. and the night shift covers 7 p.m. to 7 a.m.

Vanderbilt night shift nurses typically work a schedule that includes three days on night shift followed by two to five days off, when most switch back to a normal sleep cycle. That means most of them are shifting sleep cycles as frequently as twice a week.

“I was very surprised to find that nurses’ second most frequent strategy was the ‘no sleep’ strategy that often involved staying awake for the 12 hours before starting the night shift,” said Karen Gamble, an assistant professor of psychiatry and behavioral neurobiology at the University of Alabama at Birmingham, who worked on the study as a post-doctoral fellow at Vanderbilt. “That means they are skipping sleep for at least 24 hours straight.”

Five distinct sleep strategies
The researchers identified five distinct strategies that the nurses used to adjust their circadian clocks. The most common approach, used by about half the participants, was to sleep in late on the morning before their first night shift. A small percentage maintained a nighttime schedule on their days off. The other two strategies were intermediates.

It’s not often that you identify and characterize a human behavior for the first time, let alone one that has an effect on human health“It’s not often that you identify and characterize a human behavior for the first time, let alone one that has an effect on human health,” said Vanderbilt graduate student and co-author Chris Ciarleglio.

It was beyond the scope of the study to determine the effect that the nurses’ sleep strategies have on their performance. “It’s very difficult to differentiate between the strategies and the individual variations of the people who choose them,” Gamble acknowledged.

However, the study did ask the nurses several questions designed to assess their adaptation. For example, they asked how well adapted they felt; how long it takes them to get out of bed; how much caffeine they use; and how likely they are to fall asleep during the day. The answers to these questions indicate that the nurses who use the sleep deprivation strategy are the most poorly adapted of the five groups.

The researchers recommend that nurses should be advised to avoid the “no sleep” strategy when working nights and suggest that hospitals re-evaluate the way that they schedule nurses to reduce the frequency with which nurses switch sleep schedules.

“Most people don’t want to work at night and those that do use what works best for them and their lifestyle,” observed co-investigator Nancy Wells, director of nursing research at Vanderbilt.

Scheduling is a very touchy issue and many nurses, particularly the younger ones, like the current system because it allows them to string together a number of days off without taking vacation, she added.

The study found that night nurses used five distinct sleep strategies illustrated by this figure. The schedules cover eight days (A to H). The work shift is shown in dark gray; sleep time is shown in red; and free time is shown in light grey. The bar graph in the lower right shows how poorly adapted the nurses were who followed the different schedules. The night stay strategy was not included because it was used by so few nurses.

Genetics affect adaptation

The researchers also took DNA samples from all the participants to investigate the extent to which their circadian clocks influenced their adaptation. They determined the nurses’ “chronotype” – whether they are natural early risers (larks) or late risers (owls) – and which of seven well-known variations, or polymorphisms, in human circadian clock genes that each nurse possessed.

This information allowed the researchers to determine that larks adapt particularly well to day shifts and particularly poorly to night shifts, while owls do not adapt particularly well or poorly to either shift. In addition, they found that variants in one gene, called PER3, appear to have a major impact on the effectiveness of the no sleep strategy. Individuals with one variant of this genotype appear to respond more poorly than average to the strategy while those with the other genotype appear to respond better than average.

Vanderbilt Professor of Biological Sciences Carl Johnson, Alison Motsinger-Reif, assistant professor of statistics at Northern Carolina State University, Marshall Summar at Children’s National Medical Center in Washington, D.C. and Douglas McMahon, Vanderbilt professor of biological sciences, also contributed to the research.

The research was initially funded by Vanderbilt’s Discovery Grant program and then by a grant from the National Institute of Mental Health.

Contact:
David Salisbury, (615) 322-NEWS
david.salisbury@vanderbilt.edu

David F. Salisbury | EurekAlert!
Further information:
http://www.vanderbilt.edu

More articles from Health and Medicine:

nachricht New malaria analysis method reveals disease severity in minutes
14.08.2017 | University of British Columbia

nachricht New type of blood cells work as indicators of autoimmunity
14.08.2017 | Instituto de Medicina Molecular

All articles from Health and Medicine >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Exotic quantum states made from light: Physicists create optical “wells” for a super-photon

Physicists at the University of Bonn have managed to create optical hollows and more complex patterns into which the light of a Bose-Einstein condensate flows. The creation of such highly low-loss structures for light is a prerequisite for complex light circuits, such as for quantum information processing for a new generation of computers. The researchers are now presenting their results in the journal Nature Photonics.

Light particles (photons) occur as tiny, indivisible portions. Many thousands of these light portions can be merged to form a single super-photon if they are...

Im Focus: Circular RNA linked to brain function

For the first time, scientists have shown that circular RNA is linked to brain function. When a RNA molecule called Cdr1as was deleted from the genome of mice, the animals had problems filtering out unnecessary information – like patients suffering from neuropsychiatric disorders.

While hundreds of circular RNAs (circRNAs) are abundant in mammalian brains, one big question has remained unanswered: What are they actually good for? In the...

Im Focus: RAVAN CubeSat measures Earth's outgoing energy

An experimental small satellite has successfully collected and delivered data on a key measurement for predicting changes in Earth's climate.

The Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) CubeSat was launched into low-Earth orbit on Nov. 11, 2016, in order to test new...

Im Focus: Scientists shine new light on the “other high temperature superconductor”

A study led by scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg presents evidence of the coexistence of superconductivity and “charge-density-waves” in compounds of the poorly-studied family of bismuthates. This observation opens up new perspectives for a deeper understanding of the phenomenon of high-temperature superconductivity, a topic which is at the core of condensed matter research since more than 30 years. The paper by Nicoletti et al has been published in the PNAS.

Since the beginning of the 20th century, superconductivity had been observed in some metals at temperatures only a few degrees above the absolute zero (minus...

Im Focus: Scientists improve forecast of increasing hazard on Ecuadorian volcano

Researchers from the University of Miami (UM) Rosenstiel School of Marine and Atmospheric Science, the Italian Space Agency (ASI), and the Instituto Geofisico--Escuela Politecnica Nacional (IGEPN) of Ecuador, showed an increasing volcanic danger on Cotopaxi in Ecuador using a powerful technique known as Interferometric Synthetic Aperture Radar (InSAR).

The Andes region in which Cotopaxi volcano is located is known to contain some of the world's most serious volcanic hazard. A mid- to large-size eruption has...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Call for Papers – ICNFT 2018, 5th International Conference on New Forming Technology

16.08.2017 | Event News

Sustainability is the business model of tomorrow

04.08.2017 | Event News

Clash of Realities 2017: Registration now open. International Conference at TH Köln

26.07.2017 | Event News

 
Latest News

New thruster design increases efficiency for future spaceflight

16.08.2017 | Physics and Astronomy

Transporting spin: A graphene and boron nitride heterostructure creates large spin signals

16.08.2017 | Materials Sciences

A new method for the 3-D printing of living tissues

16.08.2017 | Interdisciplinary Research

VideoLinks
B2B-VideoLinks
More VideoLinks >>>