Scimex: A 'simple' re-organisation of shifts according to natural sleep patterns
allows workers to sleep more, and better, in their time off, according
to a German study. Researchers say that addressing 'social jetlag'
caused by a mismatch between work and sleep patterns could also have
long-term health benefits for employees.
Many of us are walking around all the time in a fog caused by "social
jetlag." That's what happens when we lose sleep because our daily
schedules don't match our bodies' natural rhythms. The condition can be a
particular problem for shift workers, who work into the night or on a
shifting schedule. Now, researchers report in the Cell Press journal
Current Biology on March 12 that sleep and workers' general wellbeing
could be improved if work schedules took workers' biological clocks into
account.
"A 'simple' re-organization of shifts according to
chronotype allowed workers to sleep more on workday nights," says Till
Roenneberg of Ludwig-Maximilian-University in Germany. "As a
consequence, they were also able to sleep less on their free days due to
a decreased need for compensating an accumulating sleep loss. This is a
double-win situation."
Such a change might have other long-term
health implications, too, although that remains to be seen. An earlier
report by Roenneberg's team, also in Current Biology, showed a link
between social jetlag and obesity, along with other unhealthy habits,
including smoking cigarettes and drinking alcohol and caffeine (see
http://www.eurekalert.org/pub_releases/2012-05/cp-sji050412.php).
The
researchers got the chance to implement their ideas about sleep and
work schedules in a real-world factory setting thanks to a former labor
director at ThyssenKrupp Steel Europe. He was interested in finding ways
to improve workers' health and lower their stress.
Factory
workers were assigned to an early, late, or intermediate chronotype
based on their normal sleep patterns. The researchers then implemented a
chronotype-adjusted ("CTA") shift schedule. People with chronotypes on
either extreme weren't assigned to the shift that would be the most
challenging for them. In other words, morning people were never made to
work late and night owls were never forced to get up early for work.
Those with an intermediate chronotype served as controls. With the new
schedule in place, the researchers watched what happened to the workers'
sleep duration and quality, social jetlag, wellbeing, subjective stress
perception, and satisfaction with leisure time.
With those
adjusted schedules, people felt more satisfied with the sleep they did
get and experienced slight improvements in their general wellbeing. It
also reduced social jetlag--the difference between the midpoint of
workers' sleep on work versus free days--by one hour. The improvements
weren't as great for those who naturally prefer to stay up late, they
found, which shows that night work is hard on everyone. After all,
Roenneberg says, even people who like to stay up late aren't nocturnal.
While
the new findings weren't exactly a surprise, Roenneberg says, it was
still "utterly satisfying to find that theory actually works in the real
and 'dirty' world. In so many cases it doesn't."
The findings
also show that flexible work schedules aren't just more convenient, they
can really make a difference in the way we feel, and perhaps also for
our long-term health. To further explore the connections between shift
work and health, the researchers are conducting experiments designed to
replicate what they've seen in their field and epidemiological studies
in laboratory mice. They hope the evidence will ultimately lead to
changes in work cultures and in the way people generally choose to
manage their time.
"We know that sleep has important implications
not only on physical health but also on mood, stress, and social
interactions, so that improving sleep will most probably result in many
other positive side effects," says Céline Vetter, the first author of
the study.