MadSci Network: General Biology

Re: Although it is essential, does our body actually age as we sleep?

Date: Thu Jan 19 19:07:30 2006
Posted By: Tye Morancy, Staff, Medical Physicist/Dosimetrist, Beth Israel Deaconess Medical Center
Area of science: General Biology
ID: 1135463679.Gb

Hello David,

I don't know if you have heard the expression, but only questions not 
asked are considered stupid questions...its a good one and it may come 
out of something that has surfaced recently in the news and emerging 
studies, but with a twist...

Everyone knows without the proper amount of sleep, as you point out, the 
mind will be a little sluggish the next day.  Scientists are beginning to 
realize that sleep is not just a mental recharger, but also important for 
the body as well.  When a person sleeps, the body and mind are working 
just as hard as when the person is awake, correcting chemical imbalances, 
assuring proper blood sugar levels for the next day, and maintaining the 
memory.  In a highly industrialized nation where the light bulb has 
expanded the working day into 24 not 12 hours, it is becoming apparent 
that more and more people are becoming sleep deprived.  With that 
deprivation comes not only a mental deficiency but also a physical one. 

It is not quite clear what physically happens in the body when one 
sleeps.  Although scientists can read brainwaves on an EEG, they are not 
sure when exactly the brain is doing, although they acknowledge that 
dreaming is a large part of it.  When the body is sleeping, the brain 
goes through four different stages, called the REM (Rapid Eye Movement) 
sleep cycles.  At different stages, the brain is active in different 
ways.  In the first stages of sleeping, the body begins to relax, the 
heart rate slows, and people often feel as though they are falling or 
otherwise weightless.  As the body slips into the second and third stages 
of the cycle, it is very apparent that the brain is not acting in the 
same way (i.e. emitting the same brain waves) as when the body is awake, 
but nevertheless the activity is still there.  This is where your body 
performs daily maintenance and healing, and where deep restful sleep 

If the body does not go through enough REM cycles, it cannot fully heal 
itself, making the body act sluggish the next day.  Some signs of sleep 
deprivation include reduced energy, greater difficulty concentrating, 
diminished mood, and slower reaction time.  Pain may be intensified by 
the physical and mental consequences resulting from the lack of sleep.  
Thus, staying up all night to study for that test or finish that 
presentation actually is more detrimental than originally thought.  The 
memory is also affected.  During sleep, the brain may recharge its energy 
stores and shift the day's information that has been stored in temporary 
memory to regions of the brain associated with long-term memory. 

Sleep deprivation also weakens the immune system, preventing the body 
from being able to ward off attacks.  But, it also affects the chemical 
balances within the body.  Men, who are normally healthy, start to show 
affects of aging after only a few nights of less than adequate sleep.  In 
a study done at the University of Chicago, Dr. Eve Van Cauter found 
that, "after four hours of sleep for six consecutive nights, healthy 
young men had blood test results that nearly matched those of diabetics. 
Their ability to process blood sugar was reduced by 30 percent, they had 
a huge drop in their insulin response, and they had elevated levels of a 
stress hormone called cortisol, which can lead to hypertension and memory 
impairment".  Such physical effects were unheard of before this study, 
and as a result, scientists are now looking into connections with lack of 
sleep and obesity.  In this matter, it strikes me that perhaps you are 
associating the aging factor with the information regarding lack of sleep 
and the damage that builds up...

In addition, another such consideration is how the body regulates sleep.  
The body is monitored by the Circadian Rhythm, a natural internal clock 
that resets itself every 24-hours.  This "clock" system results in the 
release of different chemicals in the body, depending on if it thinks the 
body needs to sleep or be awake.  It is most easily set by direct, or as 
scientist are now discovering, indirect light. It is a common fact that 
it is easier to sleep with a light on than without, and scientists are 
now realizing that is because of the Circadian Rhythm.  What this means 
is that every time you turn on a light, you are resetting the Rhythm just 
a little, making the individual cells within the body not release 
chemicals or produce the necessary proteins at the right time.  Resetting 
the Rhythm also means that the body is working overtime, making it more 
out of balance and less efficient. Thus, not only are the necessary 
chemicals imbalanced, but the body will age faster as it is forced to 
work for longer and longer hours without being able to restore itself.

I apologize for expounding so much...but I wanted to be sure to cover all 
the details that I thought might apply to this aging connection you are 
inquisitive about as it applies to sleep habits...

Thanks for the question and I hope that this helped you out...

Tye "Mad Scientist"

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