by Melanie Haiken
Would you prioritize sleep if you knew it kept your immune system
strong? That’s the question the American Academy of Sleep Medicine wants
you to ponder this week. Lost in the hoopla surrounding Independence
day was the publication of some eye-opening (or eye-shutting) research
by the American Academy of Sleep Medicine showing that the immune system
responds sharply to sleep loss.
In the study,
intimidatingly named “Diurnal Rhythms in Blood Cell Populations and the
Effect of Acute Sleep Deprivation in Healthy Young Men,” Researchers at
the Erasmus MC University Medical Center in Rotterdam, the Netherlands,
and the University of Surrey in the UK measured white blood cell counts
in young men who sleep eight hours and men whose sleep was restricted,
and found a spike in white blood cells, particularly those called
granulocytes, released in response to immune system threat.
The researchers’ conclusion: Severe sleep loss jolts the immune system just as stress does (read on for more on stress).
Sleep Loss Quadruples Stroke Risk
In addition to shocking your immune system, lack of sleep also raises
your stroke risk – even if you’re relatively young and healthy. New
research, presented last month at SLEEP 2012, found that those who cut
back their sleep to less than six hours of sleep a night are at 4.5
percent greater risk of having a stroke compared with those who slept 7
to 8 hours a night. Though researchers don’t know the exact mechanism,
it seems that chronic lack of sleep causes inflammation, elevates blood
pressure and heart rate, and affects glucose levels, leading to a much
higher stroke risk in the sleep-deprived.
Most concerning, though, is that the 5,000+ people studied
were healthy, middle-aged adults with a body mass index in the normal
range — not those typically considered at high stroke risk. And their
sleep loss wasn’t as extreme as in the immune study; these folks
reported getting less than six hours of sleep a night – the amount that
30 percent of the American population reports getting.
For some tips on getting to sleep more easily, see 5 Foods to Help You Sleep
Stress Sabotages Your Immune System, Too
This isn’t news; study after study has shown that stress raises our
risk of cancer, heart disease, allergies, and susceptibility to colds
and flu. What’s new is that researchers at Carnegie Mellon think they
now know how this works. The key, they say, is cortisol, the stress
hormone released whenever we feel fear, worry, or anxiety. Cortisol is
supposed to give us a jolt of energy, enabling us to react to and run
away from the lion as it were. But it appears that when our systems are
constantly bathed in cortisol, the body loses its ability to regulate
inflammation.
Here’s how it works. Cortisol has a secondary function of controlling
the body’s inflammatory response to immune system triggers. But over
time, with constant exposure to stress and therefore cortisol, tissues
become less sensitive to cortisol, releasing less of their
anti-inflammatory substances. (A similar process occurs with diabetes,
as chronically elevated insulin leads to insulin resistance.)
The Carnegie Mellon team,
headed by Sheldon Cohen, ran two tests of this theory. First they
exposed healthy adults to cold viruses, isolating and monitoring for
five days afterwards. People who’d recently been under stress showed
increased resistance to cortisol. In a second test, the researchers
found that participants had higher numbers of cytokines, which trigger
inflammation.
So what does it all mean? That when you get stressed out and stop
sleeping, or stop sleeping well, you get sick. (Think back to college,
when you’d get a horrible flu or even pneumonia or mono, right after
finals were over.) That probably doesn’t seem that concerning; we’ve
dealt with the post-all-nighter flu all our lives. But this year has
also seen convincing research that the body’s immune response is key to
protecting us from serious disease, such as cancer, and that
inflammation is a key precursor to heart attack, stroke, diabetes, and
other life-threatening diseases. In fact, ongoing research is underway
to document the effects of stress and sleep loss on shortening lifespan.
Source: http://www.forbes.com/sites/melaniehaiken/2012/07/05/how-stress-and-sleep-loss-are-shortening-your-life/
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