Page 79 - BBC - The Scientific Guide to a Healthier You

ARE YOU SLEEP-

DEPRIVED

OR FATIGUED?

Researchers use a sleep
latency test to find out
whether people who are
constantly tired are
sleep-deprived or
fatigued for other
reasons. If you lie down
somewhere quiet during
the day and fall asleep
within a few minutes,
then you are either
lacking sleep or
potentially suffering
from a sleep disorder. If
you’re still awake after
20 minutes, you’re
deemed to be well rested
with no sleep debt.

immune responses. Studies have shown that who indicated they felt tired in the two weeks
low-grade inflammation robs mice of their before samples were collected for the UK
energy to run on a wheel. This suggests that Biobank. They found a genetic link between
underlying tissue inflammation – whether it’s those who reported tiredness and those prone
in response to a virus, a long-term condition to diabetes, schizophrenia, high cholesterol or

or a problem with cytokine regulation – can obesity. “This raises the possibility of a genetic
be enough to make us feel weary. Scientists link between tiredness and vulnerability to
in the Netherlands have now started a major physiological stress,” said the team, led by Prof
new trial to find out whether anakinra, Ian Deary. But the researchers also said that the
an anti-inflammatory drug that blocks a majority of people’s differences in self-reported
particular cytokine, brings an improvement tiredness can be put down to environmental
in people with CFS/ME. causes rather than genetic factors. So how we
Prof Newton is clear that these related live our lives and what happens to us, is of the
underlying physical vulnerabilities may be a utmost importance.
factor in everyone’s continuing tiredness – not Furthermore, the significance of our
just CFS/ME sufferers. “The day-to-day fatigue relationship to daylight is becoming increasingly
that GPs see definitely relates to chronic illness. clear. For decades, we’ve been told that
The two are not separate,” she says. keeping regular habits and sleeping hours is
important. Now, research has confirmed the
NATURALLY SLEEPY importance of a part of the brain called the
There’s new research to suggest some of us suprachiasmatic nucleus (SCN), a group of cells
may simply have been born with a physical in the hypothalamus that responds to light
and psychological susceptibility to tiredness. signals fed from the eye. When it’s light, the
Researchers from the University of Edinburgh
GETTY analysed the genetic make-up of 111,749 people SCN messages other parts of the brain to release
hormones that make us feel alert and when 5

BBC SCIENCE FOCUS MAGAZINE COLLECTION 77