Biological Rhythms

Health Courses->Stress Management->Biological Rhythms

Harmonious Biological Rhythms

In the morn of life we are alert, 
we are heated in its noon, 
and only in its decline do we repose.
                                           Walter Savage Landor

Driven by millions of years of evolutionary adaptation to the diurnal, light and dark rhythms of the planet, our daily biological cycles are quite ingrained. Such well established, efficient body functions do not readily tolerate our modern day tampering.

The sun rises in the east. Our bodies stir from sleep. Not only from the increase in light penetrating our eyelids, but also because the body was already preparing to meet the sun. It has been conditioned for eons to know when the sun will rise today, whether cloudy or clear. The body prepares by making innumerable biochemical and neurological changes. Body temperature begins to rise from an early morning low. This comes from a complex neuro-hormonal interaction in the hypothalamus of the brain. The body needs these higher temperatures for more efficient enzymatic and biochemical operation during the day. Blood sugar also begins to elevate to provide for the increase in energy needs. Hormones fluctuate in concentration and activity. Fluid balance is altered. Both red and white blood cell counts change. The reticular activating system of the brain, the awareness control center, begins to let more sensory impulses into our awareness. Sometimes it does so slowly, with the pleasant remembrance and review of an early morning dream, and sometimes it is forced to activate more quickly: with a gear-grinding noise of the morning alarm clock BBRRRIIIINNNNGGG.

As the morning comes into full swing many things alter our physiological workings. Light, whether natural or artificial, its wavelength, intensity, position and movement all affect our internal, neuro-chemical fluctuations. What we are doing, and how intensely we do it, contributes to these internal regulatory mechanisms. The nutritional or non-nutritional substances we take in help determine how our biochemicals will be able to respond to the ancient imperatives of “standard morning operating procedures.” Substances like caffeine severely and adversely alter our normal biological rhythms.

The afternoon intensity and position of the sun, coupled with our activities, stresses, dietary intake, and evolutionarily conditioned biorhythms, continue to change our internal neuro-biochemical workings. Sunlight and our ancestral programming drive our bodies to natural, healthy functioning. Our daily activities and lifestyle choices can either assist this healthy, pre-programmed operation, or foul it up.

The same is true as the sun sets in the west and our bodies start to wind down. The more we listen to our bodies and the rhythms of the natural world and attune ourselves to those healthy rhythms, the better we will function. Just as the body is driven into activity during the day by the sun and eons of biological conditioning, it is programmed into quiescence at dusk.

We so often tamper with these natural rhythms:

  • light and dark;
  • artificial light instead of sunlight;
  • rhythms of activity and sleep;
  • artificial stimulants to stay awake when our bodies’ natural sense is to rest;
  • sedatives to confuse the nervous system to calm down when something else is driving it to vigilance.
    This causes STRESS!

Some of these disturbances to normal biological rhythms are temporary, transient conditions like jet lag or one night of no sleep. The effects might be disruption of normal functioning for a few days to a week before we recover fully. But many people suffer from multiple, daily, repetitive, cumulative assaults on healthy biorhythms. Everyone knows a classic example. The person who would sleep till noon if they could because of excesses the night before but instead is awakened at 6:00 a.m. after finally hearing 10 minutes worth of ear-shattering alarm clock noise. The person is a vegetable until he can slug down several cups of caffeine with a sugary donut. Within a short period of time this sub-standard nutritional, biochemical fix is sufficient to counteract the sleeping pills taken the night before and results in a rocket-like propulsion of activity. This activity swings up and down dramatically throughout the day, being pushed and pulled by erratic blood sugar levels from poor dietary habits and content. Erratic emotions and hectic lifestyle demands further disrupt normal physiological functioning and biological rhythm regularity. Day-in, day-out, year-in, year-out the effects accumulate and with it comes an endless stream of symptoms, poor health, and lost human potential.


Kupfer, D.; Monk, T.; Barchas, J., eds. Biological Rhythms and Mental Disorders. Guilford Press, 1988.
Journal of Biological Rhythms, Guilford Publications, NY, (212) 431-9800.


Sleep that knits up the ravelled sleave of care, 
The death of each day’s life, sore labour’s bath, 
Balm of hurt minds, great nature’s second course, 
Chief nourisher in life’s feast.  

It is such a simple thing but so many of us don’t get enough sound, restful sleep.  This is a time in which the body and mind regenerates itself.  It should not be a time to short-change ourselves.  Adults need eight hours of rejuvenating sleep every night.  Many people say “I only need six.”  Or “I never get more than seven and am fine.”  Researchers have found that this is most often not true.  You may have gotten used to less sleep but under those conditions of reduced sleep time everyone performs significantly below their best functioning on mental tests, memory quizzes, perceptual accuracy,  physical performance exams, nerve response times, and health status.  Our immune system is weakened.  We are more emotionally irritable.  We often need harmful caffeine to keep us awake.  That also means that if you get five hours sleep one day of the week, sooner or later you will have to catch up on this sleep or else adverse health effects are likely, whether they are noticed or hidden. Teenagers need at least nine and one half hours of daily sleep.

It is natural for infants to sleep about 17 hours per day in two to four hour segments. From one year of age to the teen years hours of sleep decrease from 14 to 10, and these hours congregate more at night with just short daytime nap periods. Anything that disturbs these patterns disturbs health.

There is a supreme absurdity in taking artificial stimulants to keep you up at night when your natural body rhythms are encouraging you to rest.

There is more to life than increasing its speed. 

clock_smallAvoid night jobs. The economic benefits are seldom worth the adverse effect on one’s health. Swing shifts are the worst. Even temporary nighttime wakefulness, like pulling “all-nighters” for school has considerable disadvantages. Ability to concentrate, attention spans, thinking accuracy, are all adversely affected. Not to mention poor coordination leading to accidents, depressed immunity leading to infections, heightened emotional irritability leading to decreased performance in any endeavor.

There are 500,000 motor vehicle accidents with 8,000-10,000 deaths
in the U.S. per year caused by sleep deprivation. 

Sleep deprivation and biological rhythm disturbance can so adversely effect intellectual performance that it is infinitely wiser to plan a study schedule that respects biological laws. We should also mention silence as an aid to sleep. Any excessive noise, when the nervous system is already excessively irritable has a greater chance of disturbing sleep. Providing a bedroom that is insulated from external background noise is usually helpful in sleeping more soundly. This can be more than a minor problem for those light sleepers who have partners who snore.

Overall, we seldom recognize that sleep is a major component of our total well-being.


    GET MORE REST!  Make sure you are getting sufficient sleep at night.  If you need to take some 10-20 minute cat naps during the day to fend off sleepy fatigue be sure to do so.


      One very important aid for the treatment of sleep disorders is Brain Neurotransmitter Balancing.

If you have trouble sleeping at night there are many natural aids to better sleep.  Refer to the book, Comprehensive Health Care for Everyone: A Guide for Body, Mind, and Spirit, for a detailed discussion on the subject of how to get better sleep.  You will also find valuable resources for coming into a more natural harmony with your biological rhythms.

Hauri, Peter and Linde, Shirley. No More Sleepless Nights. Wiley, 1991.

American Academy of Sleep Medicine

One aspect of getting better sleep that is also important in building our health reserves is getting sufficient exposure to light.

Let There Be Light

Closely linked with sleep is the influence of light on biological rhythms, biochemical balance, neurological integrity, and psychological functioning. Light enters the eye and strikes the retina. This structure in the back of the eye changes the light energy to nerve signals that differ in intensity and wave length. Most of these signals go via the optic nerve to the visual cortex in the back of the brain for interpretation and association with other sensory inputs and motor responses. A small portion of these signals get diverted before entering the visual cortex. They go by another “energetic portion” of the optic nerve to the pineal and pituitary glands in the middle of the brain. Here the light-initiated nerve signals influence a wide array of neuro-hormonal functions throughout the body, in no small part because the pituitary gland is the “master gland” of the body and regulates many of the body’s hormonal functions. Differences in the quantity, intensity, and wavelength of light create variances of neuro-biochemical responses throughout the entire body as mediated by this nerve and hormone mechanism.

By doing research on biochemical and health differences between sighted individuals and the blind, and on people who lost sight with cataracts and then had their vision restored with surgery, we have discovered much about the potential impact that light has on biochemical balance, organ efficiency, neurological integrity, and even musculoskeletal function. A few examples: Blind individuals have a significantly more difficult time regulating internal body temperature than the sighted do because of light’s effect on the hypothalamus—which modulates much of the body’s temperature regulation.

Degree of blindness has also been correlated to degrees of developmental skeletal deformities in part due to disturbed mineral balance. Electrolyte balance has been directly correlated to the quantity of light entering the eyes. This is mediated through the renin-angiotensin-aldosterone hormone system of the pituitary, kidney, and adrenals. Quantity and wavelength of light also have been shown to help the daily balance of red and white blood cell count, blood sugar levels, menstrual cycles, kidney clearance abilities, liver detoxification capacity, antibody levels, and so on.

Since this light-nerve-hormone system formed over millions of years of evolutionary development, it responds best to natural sunlight. In fact, certain types of artificial light sources, because of differences in wavelength, intensity, movement, and position, cause a disruption of these nerve and hormone networks. It is therefore imperative to expose the eyes to sufficient quantities of natural sunlight with minimal interference from wavelength altering filters or screens like those found in sunglasses, even regular glasses or windows, particularly tinted ones.

If the doors of perception were cleansed,
man would
see things as they are, infinite.
                   William Blake

More Homework

Here are some rules of thumb to use to provide better health from light.
I. Avoid artificial light
            A. Use “full-spectrum” lighting fixtures instead of normal incandescent or fluorescent bulbs at home and work.
            B. Minimize watching television.
            C. Minimize use of computer monitors before bed.
II. Expose eyes to more natural sunlight.
            A. Spend more time outdoors.
  1. When sunglasses are needed, be sure they block 95% or more of the UV rays but minimize use of sunglasses as much as possible.
  2. Wear sunglasses at high altitudes and whenever there is significant snow or water glare in order to protect the eyes from the ill effects of intense UV rays.
  3. Use sunglasses if glare while driving impairs safety.
  4. Use contacts instead of glasses if possible. They distort light wavelength less.
  5. Cataract prone individuals or people with cataracts or eye diseases such as macular degeneration or retinitis have to be more careful in their exposure to UV radiation but get sufficient sunlight.


    Hyman, Jane. The Light Book: How Natural and Artificial Light Affect Our Health, Mood, and Behavior. Tarcher, 1990.

Light Deficit Disorders

Insufficient ocular exposure to light has been found to contribute to a number of disorders including: Seasonal Affective Disorder (SAD) also known as “winter blues”, non-seasonal depression, other mood disorders, sleeping disorders like insomnia and delayed sleep phase syndrome, visual disturbances like too much sensitivity to light, and poor night vision, fatigue syndromes, fear and anxiety disorders, child and adult hyperactivity, attention deficit disorders and learning disabilities. Part of these problems are due to insufficient exposure to natural sunlight; part are due to excessive artificial lighting exposure.

For problems such as Seasonal Affective Disorder the new treatment of choice involves exposure of the eyes to large banks of full-spectrum light for several minutes or hours every day in the winter months.


If you feel you have a light deficit disorder use the resources in this section to help resolve the issue.

Sunlight from millions of miles away gives life to our planet. It provides food for the nourishment of body, mind, and spirit. It allows us to see and interact joyously with all around us. It stimulates our nervous system to more efficiently regulate functions of both the body and the mind.


     Rosenthal, N. Winter Blues: Seasonal Affective Disorder.

How do I know about the world? Inward light! 

                                  Lao Tzu