As mentioned earlier, melatonin
production and release is controlled by the body’s “biological
clock” (suprachiasmatic nucleus) in response
to changes in daily light/dark cycles. Melatonin
levels are known to drop significantly after
childhood and serve as one of the most dramatic
markers of biological aging known. By the age
of 60, nighttime melatonin production practically
ceases, and by age 80 melatonin plasma levels
are barely detectable.
Obesity
Linked to Lack of Sleep
Sleep scientists have identified
additional links between disrupted sleep cycles
and age-related alterations in hormonal levels.
In one study, researchers from the Stan-ford
University School of Medicine have shown that
getting less than 8 hours of sleep leads to increased
levels of ghrelin, a hormone produced by the
stomach that makes people hungry, slows metabolism
and decreases the body's ability to burn fat.5
Ghrelin levels in the blood spike before meals
and drop afterward. People given ghrelin injections
become voraciously hungry, consuming up to 30
percent more calories than they normally would.6
The Stanford researchers also
discovered that inadequate sleep results in lower
levels of another appetite hormone, leptin. In
contrast to ghrelin, lower levels of leptin signal
the body that it is starving, further increasing
appetite and the drive to consume extra calories.
The Stanford study revealed
a 14.9 percent increase in ghrelin levels, and
15.5 percent decrease in leptin levels in people
who consistently slept for only five hours, compared
with those who slept for eight. These findings
are supported by previous studies that show that
people who get less than four hours of sleep
each night are 73 percent more likely to be obese
than normal sleepers.
Drop
in Growth Hormone Linked to Slow Wave Sleep
In related news, researchers
from the University of Chicago School of Medicine
have associated sleep loss with the age-related
drop in human growth hormone (GH). Growth hormone
is normally released during the most restful
phase of slow wave sleep (SWS). Growth hormone
plays a vital role in human health, stimulating
bone growth, immune function, amino acid uptake,
protein synthesis, and muscle glucose uptake.
Growth hormone also induces the burning of fat
from adipose tissues and plays a key role in
maintaining cardiovascular health.
Reduction of growth hormone
in aging humans is associated with immune system
malfunctions, increased body fat deposits, a
loss of muscle tone and overall physical strength,
thinning of skin, and diminished sexual drive.
When the Chicago researchers
monitored the sleep patterns of 149 healthy men,
aged 16 to 83 years, over a period of 14 years
they discovered that the total amount of time
spent in slow wave sleep (SWS) dropped from 19%
of total sleep in early adulthood to only 3%
by midlife. This decline in restorative slow
wave sleep was matched by major declines in the
secretion of human growth hormone.7
Elevated
Cortisol and REM
In the same study the Chicago
researchers noted a significant increase in evening
levels of cortisol in subjects 50 years and older.
These elevated cortisol levels were associated
with increased sleep fragmentation and further
declines in REM sleep. Cortisol, the body’s
principal anti-inflammatory hormone, is typically
released by the adrenal glands in response to
stress. While some cortisol is necessary, chronically
elevated cortisol levels (hypercortisolemia)
contribute to obesity, hypertension, reduced
glucose tolerance (a contributing factor in developing
diabetes), loss of bone density, decreased muscle
mass and increased neuronal death of brain cells.
Sleepless
Rats Reveal Problem in Biological Clock
Two recent animal studies seem
to confirm that problems within the body’s
cellular clock serve as a crucial source of age-related
sleep problems while suggesting that the clock
can be “reset” to more youthful levels – at
least in aged rats.
In the first study, researchers
at Washington University in St. Louis examined
cells from the suprachiasmatic nucleus (SCN)
that are responsible for generating circadian
rhythms. They discovered that the electrical
activity of these “clock cells” in
older rats was irregular when compared with the
activity of timing cells in young and middle-aged
animals. According to Erik Herzog, Ph.D., assistant
professor of biology at Washington University, "In
the case of the aged rats, many of them showed
fragmented behavioral rhythms. The cells in the
older rats were still rhythmic, but showed bouts
of activity when they normally would have rested,
and inactivity when the young animals were active.
So, the rats, like elderly humans, took naps
when they would have normally been active. Remarkably,
the cells in their biological clock reflected
this behavior.”8
Research
Links Healthy Biological Clock to Longevity
In a related study supported
by the National Institute on Aging in the US
and the Natural Sciences and Engineering Research
Council in Canada, researchers transplanted fresh
brain cells harvested from the suprachiasmatic
nucleus of young hamsters into the biological
clocks of aging hamsters. Normally, once a hamster’s
biological clock has begun to deteriorate, death
occurs within three months. However, after the
researchers transplanted the new “clock” into
hamsters whose own clocks had begun to deteriorate,
the animals lived an average of four months longer
than hamsters without the transplant – equivalent
to increasing their lifespan by an astonishing
20 percent.
According to psychologist Martin
Ralph of the University of Toronto, other therapies
might achieve similar results. "If the function
of the clock can be mimicked by a structured
lifestyle, such as more light during the day
and darkness at night, then this will work in
the same direction as the transplant works in
hamsters.”9
Poor
Sleep Linked to Early Death in Older Adults
Sleep disturbances have been
shown to double the risk of death for healthy
older adults compared to more restful seniors,
according to new research. Lying awake for 30
minutes or longer and spending a smaller percentage
of the night asleep boost the risk of death among
older adults, according to Mary Amanda Dew, Ph.D.,
and colleagues at the University of Pittsburgh
School of Medicine.
Older adults who sleep poorly
tend to have a diminished quality of life, but
the study by Dew and colleagues suggests that
sleep disturbances can have a much more serious
effect on health.
“ Interventions that
optimize or protect sleep initiation and sleep
quality in old age might not only add quality
of life but prolong life as well,” Dew
says
In eight different studies between 1981 and 1997,
the researchers used EEG monitors to observe
sleep patterns in 185 healthy adults 60 to
90 years old. Dew and colleagues then collected
follow-up information to find which study participants
had died by the year 2001.
The 66 adults who had died
were more likely in the earlier sleep studies
to lie awake for long periods, to sleep less "efficiently" through
the night and to have abnormally high or low
amounts of REM sleep, compared to study participants
who were still living at the time of follow-up.
The link between poor sleep
and earlier death remains significant, even after
adjusting for the influence of age, gender and
existing health problems, the researchers note.10
Sleep
Cycle™ for a Deeper Night’s Sleep
Though people frequently tend
to focus on falling asleep quickly, a far better
indicator sleep quality is the ability to wake
up feeling refreshed, energized and restored
the following day. Consequently, Sleep Cycle
is not intended to act like a fast-acting sleeping
pill that knocks people out quickly. Instead,
Sleep Cycle works by gently promoting a state
of calm as it initiates the natural process of
falling asleep. Over time, Sleep Cycle conditions
and improves the overall quality of sleep by
gradually extending the duration of deep, Slow
Wave Sleep (SWS) and shortening the length of
time it takes to fall into a restful slumber.
Sleep Cycle achieves this by
combining traditional herbal extracts with state-of-the-art
modern nutrients to deliver a unique, safe and
highly effective natural sleep aid.
Sleep Cycle begins with two
nutritional compounds, melatonin and 5-HTP, that
have been shown to aid in resynchronizing the
body’s biological clock to promote healthier
sleep rhythms. Sleep Cycle also contains a well-known
combination of natural plant extracts that have
been used for centuries to promote deep, restful
sleep, including Hops, Lemon balm, Passionflower,
Valerian root, Angelica, Jujube, and Polygala.
Additionally, Sleep Cycle contains L-Theanine,
an amino acid derived from green tea prized for
its ability to promote calm and relax the mind.
Finally, Sleep Cycle contains
a new, clinically researched herbal ingredient, Wulinshen,
that is derived from the traditional herb, Xylaria
Nigripes by way of a proprietary pharmaceutical
extraction and formulation process. This proprietary
compound, found only in Sleep Cycle, provides
critical and often depleted nutrients required
by the brain to assist biochemical processes
involved in promoting restful, deep sleep. Wulinshen
contains significant amounts of glutamic acid,
gamma-aminobutyric acid (GABA) and glutamate
decarboxylase. GABA's main function is to inhibit
excitatory neuro-activities by exerting a tranquilizing
effect on the central nervous system. Glutamate
decarboxylase (GAD) supports the synthesis of
GABA, while glutamic acid assists the uptake
of GABA to specific brain cell receptors.
Summary
As sleep scientists continue
to investigate the body’s biological clock,
existing research has already shown how disrupted
sleep patterns are linked to significant age-related
alterations in hormone production. One well-established
example is the age-related decline in melatonin,
the principal hormone produced by the pineal
gland (Fig. 1). Melatonin is a vital neurohormone
involved in regulating the neuroendocrine system
and controlling essential functions such as metabolism,
sex drive, appetite, and sleep. Melatonin also
exerts powerful antioxidant activity and plays
a key role in the immune system by preventing
the proliferation of cancer cells.
References
1. 1. NIH Office of Communications
and Public Liaison, National Institute of Neurological
Disorders and Stroke, http://www.ninds.nih.gov/disorders/brain_basics/understanding_sleep.htm
2. http://www.sleepfoundation.org
3. E. J. W. Van Someren. “Circadian and
sleep disturbances in the elderly.” Experimental
Gerontology, Volume 35, Issues 9-10, December
2000, Pages 1229-1237.
4. University Of Pittsburgh Medical Center. “Deterioration
Of Sleep During Middle Age Related To Changes
In The Biological Clock.” ScienceDaily
25 June 1998.
5. Stanford University Medical Center. “Stanford
Study Links Obesity To Hormonal Changes From
Lack Of Sleep.” ScienceDaily 9 December
2004.
6. Plasma ghrelin levels after diet-induced weight
loss or gastric bypass surgery. N Engl J Med.
2002 May 23;346(21):1623-30.
7. Age-Related Changes in Slow Wave Sleep and
REM Sleep and Relationship With Growth Hormone
and Cortisol Levels in Healthy Men Eve Van Cauter,
PhD; Rachel Leproult, MS; Laurence Plat, MD JAMA.
2000;284:861-868.
8. Washington University In St. Louis (2001,
August 14). Sleepless Aged Rats Show Biological
Clock Problems. ScienceDaily. http://www.sciencedaily.com_
/releases/2001/08/010814063122.htm.
9. University Of Toronto (1999, March 29). Research
Links Healthy Biological Clock To Longevity.
ScienceDaily, http://www.sciencedaily.com_
/releases/1999/03/990325111049.htm.
10. Center For The Advancement Of Health, 2003,
February 4.
