Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Sleeping in on the weekends doesn't fix all the deficits caused by workweek sleep loss

10.10.2013
Article published in the American Journal of Physiology-Endocrinology and Metabolism

In many modern societies, adults often sacrifice sleep during the workweek to make time for other demands, then snooze longer on the weekends to recoup that lost sleep.

Research has shown that even a few days of lost sleep can have adverse effects, including increased daytime sleepiness, worsened daytime performance, an increase in molecules that are a sign of inflammation in the body, and impaired blood sugar regulation. These last two could be partially responsible for why sleeping less negatively affects health in other ways and shortens the lifespan.

Though many people believe they can make up sleep lost during the workweek by sleeping more on the weekend, it's unknown whether this "recovery" sleep can adequately reverse these adverse effects.

To help answer this question, researchers led by Alexandros N. Vgontzas of the Penn State University College of Medicine, placed 30 volunteers on a sleep schedule that mimicked a sleep-restricted workweek followed by a weekend with extra recovery sleep. At various points along this schedule, the researchers assessed the volunteers' health and performance using a variety of different tests.

The researchers found that the volunteers' sleepiness increased significantly after sleep restriction, but returned to baseline after recovery sleep. Levels of a molecule in blood that's a marker for the amount of inflammation present in the body increased significantly during sleep restriction, but returned to normal after recovery. Levels of a hormone that's a marker of stress didn't change during sleep restriction, but were significantly lower after recovery. However, the volunteers' measures on a performance test that assessed their ability to pay attention deteriorated significantly after sleep restriction and did not improve after recovery. This last result suggests that recovery sleep over just a single weekend may not reverse all the effects of sleep lost during the workweek.

The study is entitled "The Effects of Recovery Sleep After One Workweek of Mild Sleep Restriction on Interleukin-6 and Cortisol Secretion and Daytime Sleepiness and Performance." It appears in the American Journal of Physiology-Endocrinology and Metabolism, published by the American Physiological Society. The article is available online at http://bit.ly/17TeQgg.

Methodology

The researchers recruited 30 healthy adults who were normal sleepers and put them on a 13-day schedule that involved spending nights in a sleep lab. For the first four nights, the subjects were allowed to sleep for 8 hours, setting a baseline for a healthy, normal amount of sleep. For the next six nights, the researchers woke the subjects up 2 hours earlier. For the following three nights, the subjects were allowed to sleep for 10 hours. The researchers monitored the volunteers' brain waves during these sleep sessions. At three points during the 13-day schedule, the volunteers spent whole days at the lab taking part in various tests: after the 4 days of baseline sleep, after 5 days of restricted sleep, and after 2 days of recovery sleep. On these days, the subjects had catheters inserted into their arms, and the researchers sampled blood every hour, testing it for levels of interleukin-6 (a marker of inflammation) and cortisol (a hormone secreted during stress). They also participated in a test of how quickly they fell asleep when allowed to nap several times during those days (an objective measure of sleepiness) and filled out questionnaires to assess how sleepy they felt (a subjective measure of sleepiness). To assess their performance, they participated in a test in which they were asked to press a button whenever a dot appeared on a screen, which measured how well they were able to pay attention.

Results

Not surprisingly, the researchers found that after 5 days of restricted sleep, the subjects were significantly sleepier on both objective and subjective tests compared to baseline levels. Their interleukin-6 levels increased sharply during restricted sleep, though their cortisol levels remained the same. Their performance on the attention test deteriorated. After 2 days of recovery sleep, both objective and subjective tests showed that the volunteers were less sleepy. Their interleukin-6 levels reduced, and their cortisol levels decreased significantly compared to baseline, possibly suggesting that the volunteers were sleep deprived before the study started. Notably, their performance on the attention test didn't improve after recovery sleep.

Importance of the Findings

Though many indicators of health and well being improved after recovery sleep, these findings suggest that extra sleep may not fix all the deficits caused by lost sleep during the workweek.

"Two nights of extended recovery sleep may not be sufficient to overcome behavioral alertness deficits resulting from mild sleep restriction," the authors write. "This may have important implications for people with safety-critical professions, such as health-care workers, as well as transportation system employees (drivers, pilots, etc.)."

The authors also suggest that even though these results provide some insight on the health effects of a single week of sleep loss and recovery, reliving the cycle over and over again may have more significant health effects that this study wouldn't show.

"The long-term effects of a repeated sleep restriction/sleep recovery weekly cycle in human remains unknown," they write.

Study Team

In addition to Dr. Vgontzas, the study was conducted by Slobodanka Pejovic, Ilia Kritikou, Michele L. Shaffer, and Edward O. Bixler of Pennsylvania State University, Maria Basta of Pennsylvania State University and the University of Crete, Marina Tsaoussooglou and George P. Chrousos of National and Kapodistrian University of Athens, David Stiffler of Pennsylvania State University and the New York School of Medicine, and Zacharias Stefanakis of the University of Crete.

Physiology is the study of how molecules, cells, tissues, and organs function in health and disease. Established in 1887, the American Physiological Society (APS) was the first US society in the biomedical sciences field. The Society represents more than 11,000 members and publishes 14 peer-reviewed journals with a worldwide readership.

NOTE TO EDITORS: To schedule an interview with a member of the research team, please contact Donna Krupa at dkrupa@the-aps.org, @Phyziochick, or 301.634.7209. The article is available online at http://bit.ly/17TeQgg.

Donna Krupa | EurekAlert!
Further information:
http://www.the-aps.org

More articles from Studies and Analyses:

nachricht Smart Data Transformation – Surfing the Big Wave
02.12.2016 | Fraunhofer-Institut für Angewandte Informationstechnik FIT

nachricht Climate change could outpace EPA Lake Champlain protections
18.11.2016 | University of Vermont

All articles from Studies and Analyses >>>

The most recent press releases about innovation >>>

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

Im Focus: Shape matters when light meets atom

Mapping the interaction of a single atom with a single photon may inform design of quantum devices

Have you ever wondered how you see the world? Vision is about photons of light, which are packets of energy, interacting with the atoms or molecules in what...

Im Focus: Novel silicon etching technique crafts 3-D gradient refractive index micro-optics

A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.

Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...

Im Focus: Quantum Particles Form Droplets

In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.

“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...

Im Focus: MADMAX: Max Planck Institute for Physics takes up axion research

The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.

The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...

Im Focus: Molecules change shape when wet

Broadband rotational spectroscopy unravels structural reshaping of isolated molecules in the gas phase to accommodate water

In two recent publications in the Journal of Chemical Physics and in the Journal of Physical Chemistry Letters, researchers around Melanie Schnell from the Max...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ICTM Conference 2017: Production technology for turbomachine manufacturing of the future

16.11.2016 | Event News

Innovation Day Laser Technology – Laser Additive Manufacturing

01.11.2016 | Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

 
Latest News

IHP presents the fastest silicon-based transistor in the world

05.12.2016 | Power and Electrical Engineering

InLight study: insights into chemical processes using light

05.12.2016 | Materials Sciences

High-precision magnetic field sensing

05.12.2016 | Power and Electrical Engineering

VideoLinks
B2B-VideoLinks
More VideoLinks >>>