In a German lab, volunteers are being paid to explore one of space travel’s biggest challenges –
helping astronauts get a better night’s sleep.

I AM inside an underground research
laboratory surrounded by forest near
Cologne, Germany. The walls are white,
harshly illuminated by concealed
lighting, there are no windows and
few pictures. The room I am standing
in contains a single bed, a computer
and a disturbing painting of an alien
landscape, with a giant flowering plant
and weird futuristic space train. There
are cameras fixed to the ceiling, watching
my every move.
Isolated from the outside world, it
could be any time of the day or night. I
feel so disconnected from reality, I might
no longer even be on Earth. This is exactly
what the designers of this German
space agency – DLR – facility intended.
‘Envihab’ is the perfect environment for
scientists and physicians to test the how
spaceflight affects the human body.
The latest experiment involves
studying the effects of lack of sleep –
a real problem for astronauts on the
International Space Station (ISS). “In
principle they could get enough sleep,
around eight hours a night,” says Eva-
Maria Elmenhorst, who is conducting
the study. “But most astronauts only
sleep five or six hours and that is not
Many of us limp through the day on
barely enough sleep, with a steady supply of strong coffee to keep us going. As
it happens, when I speak to Elmenhorst, I
have been up since 04.15 to catch my flight
to Germany. But I only have the relatively
limited task of asking her some questions
and recording the answers. Astronauts,
on the other hand, are travelling at some
27,000km/h (17,000mph) around the
planet and living just centimetres from
the cold vacuum of space. A wrong
decision, moment of carelessness or loss
of concentration could mean the difference
between life and death for themselves
and the rest of the crew. Imagine precisely docking several tonnes of
spacecraft on only five hours sleep.
But getting a good night’s sleep
in space is not easy. There are
no beds or pillows – astronauts
sleep strapped to the wall in
sleeping bags. And that’s not all.
“There’re probably several reasons
they don’t sleep properly,” says
Elmenhorst. “Isolation, a sunrise
every 90 minutes and [with the
ventilation system] it’s quite noisy
in the ISS.” Often, astronauts
have to work shifts to monitor
experiments or capture visiting
supply ships.
She hopes the research will
benefit shift workers on Earth and
others – such as doctors and nurses
– who often work long hours
making life and death decisions
with insufficient sleep
To investigate how this lack
of sleep affects astronauts’
performance, Elmenhorst’s team
has been subjecting groups of
paid volunteers to sleep deprivation
experiments. “We want to show how sleep
loss affects cognitive function,” she says,
“and how some people cope better than
As well as astronauts, she hopes the
research will benefit shift workers on Earth
and others – such as doctors and nurses
– who often work long hours making life
and death decisions with insufficient sleep.
In Germany alone, Elmenhorst says some
16% of employees regularly work shifts
and many workers, in often safety-critical
jobs, get less than the recommended eight
hours a night.
The volunteers in Elmenhorst’s experiments were given a range of
daily tasks to perform, including
memory exercises, reaction time tests
and repetitive computer games. For five
nights they were only allowed to sleep for
five hours a night. This was followed by
a recovery period of eight hours before a
mind-frying 38-hour stint when they had
to remain awake.
The doctors monitored their subjects’
brain activity using caps – like hairnets
– containing multiple electrodes, took
blood samples and conducted MRI scans.
Someone was always around to stop us
falling asleep – Lucas, a volunteer
“We are interested in the fundamental
mechanisms in the brain that control
sleepiness,” says Elmenhorst. “Even one
night without sleep we see hormonal
changes in the body.”
For the volunteers – motivated, they
confess, primarily by the money – sitting
around watching TV and chatting for the
two week experiments was more difficult
than they imagined. “Staying awake was
hard,” says Lucas, a student who took
part in the study. “Someone was always
around to stop us falling asleep.”
“The only things we could do were
to talk to each other, watch TV or play
with the laptop,” says another volunteer,
Magdalena, who is training to be a
teacher. “There was always someone
saying ‘Magdalena…are you awake?
Magdalena, wake up!’”
To ensure the volunteers didn’t doze
off, they were constantly monitored by
members of the research team – who sat
with them or watched them on closedcircuit
monitors. If a volunteer’s eyes
closed for too long, a researcher would
prod them awake.
As the days went on, Lucas became
aware that his memory and dexterity
were deteriorating. “I noticed how bad
we were doing on the tests,” he says. “I
now try to get as much sleep as possible –
no more all-nighters to revise.”
As well as finding an expected decline
in mental performance, the research team
discovered an even more disturbing
biological change in the volunteers. “We
have shown that five hours of sleep
a night over five days slows glucose
metabolism and there are hormonal
changes in the body,” says Elmenhorst.
This correlates with studies suggesting
people who regularly work shifts suffer
disproportionately from diabetes and
high blood pressure.
Ensuring astronauts get enough sleep
will become more important than ever
The ultimate aim of the on-going
research is to develop better daily
schedules for astronauts, to prevent
them from becoming too tired. As longduration
missions become more common
and humanity moves towards a spacefaring
civilisation ensuring astronauts
get enough sleep will become more
important than ever.
When I speak to Elmenhorst, the
latest group of volunteers has just left
the Envihab facility. The irony is that
she could now do with a good night’s
sleep. “Most mornings I’ve had to get
up at 05.00 to conduct this study,” she
confesses, “and that had negative effects
on my cognitive functions too.

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