By Basil E. Gala, Ph.D.
In Search of Meaning
Homeostasis is a fundamental principle in nature, both in living and inanimate systems, operating practically everywhere. It’s based on the control loop of feeding a negative or positive transform of the output back to the input of the system. Each living thing seeks to maintain a state of homeostasis or equilibrium in the face of disturbances. The body must maintain its temperature within certain boundaries for optimal functioning. Hypothermia kills. We sweat in heat and the moisture evaporates on the skin to cool us down. Dogs stick out their tongues to cool themselves. Heat exhaustion can also kill. We shiver when we’re cold to warm up or we seek shade and water, move more slowly or remain inactive under our sombreros. Today most people just turn on air conditioners in high heat. Using our technology, we adjust to difficulties by forcing the outcomes for speed and immediate gratification, ignoring the natural rhythms of nature to our peril and damage. We should seek homeostasis, stability and order, with simple, natural means, because thus we save resources, the environment, and our health.
For thousands of years we cultivated our lands and kept animals for our nutritional needs. We employed horses, donkeys, water buffalo, even elephants for transportation. We used the droppings of our animals in compost piles as fertilizer in a sustainable way. Our boats and ships moved with oars or sails; how beautiful were our sailing ships, going with the wind, not forcing their way on the water with fuming engines. The boats were not fast, not that safe, but they were good not polluting the Earth.
I have a habit of using what I call low-tech air conditioners: fans, wet towels or shirts, a breeze in the shade of an arbor.
Others are more extreme than I. Stories are told of Buddhist monks who with meditation can keep warm when naked on a frozen lake, a test of their training. Others sit in the burning sun without suffering from the heat.
Surely, how we react to stresses from the environment certainly changes what we experience from the disturbance to our homeostasis. If we face stresses calmly, they affect us less severely.
Incidentally, the word homeostasis comes from the Greek, meaning standing the same. Equilibrium is maintained by means of feedback mechanisms: sensors in the body return signals of extreme conditions back to the body and cause it to change in response to reduce the effect. Such is the way the pupils of our eyes act. When light is strong our pupils contract, the opening for light gets smaller, so the retina does no suffer so much.
Usually, body mechanisms for excessive heat or cold work reasonably well at the cost of some discomfort. But when we accustom ourselves to seek relief right a way with mechanical devices, we lose some of our ability to adapt. Each generation in wealthy societies tends to become less adaptable in this respect. Younger people complain of heat or cold when I am quite comfortable at 55 or 85 degrees.
Temperature control is vital, but homeostasis applies to many situations in the body and in communities. Blood sugar must be maintained within a range, or the body suffers with dizziness or stupor. Within the normal range, when blood sugar drops hunger rises and after twenty or so minutes of slow eating, rising blood sugar signals satiety; or that’s what should happen.
Similarly, the heart rate and blood pressure may move up rapidly to speed up action in emergencies, but they must come down to a lower levels for other work or rest. Without sufficient respite from repeated emergencies, these readings can get stuck at high levels with disastrous consequences for health. After an emergency, use common sense and rest well.
Cholesterol is needed in the brain and elsewhere, produced in the liver and absorbed from food, it serves vital functions. When excessive, however, it clogs arteries with plaque. Cholesterol that your body needs is produced in the liver; dietary cholesterol comes mostly from meat, poultry, fish, dairy, or eggs. Proper homeostasis of cholesterol requires that we eat much less of such foods than we do today.
Again, consider energy production. We want energy to work and play, but excessive body energy production depletes our strength and reduces our stamina for activities of long duration. We become exhausted and collapse when we continue in feverish action for too long.
Hundreds or even thousands of such homeostatic feedback loops operate in the body to maintain stability in action, usually pretty effectively. Occasionally, such systems go out of whack when a homeostat fails to function properly.
Take the case of acid in the stomach, normally at about pH 4.5 versus the rest of the body’s pH 7.5. The stomach churns the food and dissolves it with the help of strong acids; too much acid, however, can damage the stomach lining, tough tissue as it is, and cause ulcers. Normally, a homeostat limits the amount of acid secreted to tolerable limits. Excessive stress can interfere with the operation of this feedback loop. This past year stress caused me to have two episodes of severe stomach pain requiring a prescription antacid.
Besides our bodies which have evolved, mechanical and electronic systems we have designed also subscribe to homeostasis. An automobile engine operates for long periods of time in normal mode without much maintenance; a racing car engine has to be rebuilt after each competitive event.
Both biological and mechanical systems function best and last the longest when working in their normal, linear, operating range, with upper and lower bounds of output. When operation moves to extremes, where non-linear effects take hold, the results are unpredictable and often damaging. In human terms, we do our best living in our comfort zone, with moderate stress and less wear and tear of our parts.
True, outside of our comfort zone of functioning lies opportunity and growth, but also hazards to our health and even our existence. When you’re there, proceed cautiously.
Be cautious with water tanks, including an ordinary toilet; they fill up quickly; then as a balloon inside rises with the water and a lever attached to the balloon slowly shuts off the flow of water so we don’t waste the water with overfilling and cause damage with flooding.
We also don’t want to waste electrical energy. A thermostat with a thermometer provides homeostatic order in air conditioning our homes, so that they don’t get too hot or too cold. Our home’s temperature fluctuates between upper and lower limits that we set, so we’re comfortable and electric energy is used efficiently.
Among living things, an organism in good homeostatic order operates efficiently and effortlessly; it feels relaxed and at peace, not stressed and depressed. It is so with animals as well as with plants. A plant which gets too much sunlight or wind curls up its leaves and flowers to reduce exposure.
When we lack water we thirst; when thirst is slated, we’re no longer thirsty. People who don’t experience thirst can become dangerously dehydrated.
When the stomach is empty a homeostat signals hunger and the animal searches for food. Hunger and satiety are normally well controlled by leptin and ghrelin hormone levels in the blood. We humans, however, follow habits, desires for delicacies, and eating fashions causing imbalances in nutrition which sometimes make us fat, undernourished or both.
Again, consider the sleep cycle; it’s controlled by a cluster of neurons in the brain with endogenous activity—a biological clock. Keep that clock as regular as possible for good physical and mental health. When we’re tired or low in energy we naturally get drowsy and seek sleep, which refreshes and replenishes our neural batteries. Take a nap, but do your main sleeping at night. Don’t take stimulants to keep going with work or play, causing harm to your body’s homeostatic system.
People who don’t maintain a regular sleeping and waking cycle tend to live in perpetual jet lag. Circadian rhythms in the brain may get permanently disrupted.
A regular sleeping and feeding cycle is essential to good performance and longevity. We used to joke that my dad lived by the clock: he slept, woke up, ate and exercised at very regular times. He had an unusually fine clock in his brain and knew time with precision without having to look at his watch. He never had to use an alarm. He woke up whenever he needed to wake up or to wake up others. He lived a healthy life for 100 years, quickly recovering from accidents and infections.
Animals also have a reproductive cycle, most regular in females with estrus. This cycle is triggered by ovulation in females and semen accumulation in males and is followed by hormonal changes, and mating behavior. Afterward, ease and relaxation set in. Again we humans often violate this natural cycle at some cost.
Communities also function with the homeostasis principle; so do their economies. Supply and demand is cyclical, as well as business activity, rising and falling in waves with feedback controls, like the temperature in your thermostatically controlled house.
Indeed ebb and flow rule in human affairs. An economy rises as people become optimistic, spending their savings to buy goods and services. Producers augment their facilities to make more product, to cash in during the tide of spending, hiring more workers, who earn wages to spend. This process is positive feedback, causing a high level wave in the business cycle.
Eventually negative feedback kicks in with people exhausting their cash and credit, cutting back on their spending, and sending the economy into a downward wave. Sometimes the cycle brings a boom, which is followed inevitably by a bust—bankruptcies, layoffs, unemployment, suffering. Homeostasis has failed.
Unfortunately, governments tend to ignore the lessons of homeostasis for the economy and do not properly prepare for shocks, which are bound to occur on occasion.
Severe shocks occasionally push a person or group out of kilter, out of balance. Such shocks are illness, accident, wars, or other disasters. Then an individual, a family, or a community can suffer breakdowns and even death.
Homeostasis is essential to survival; that is why it exists. When it functions properly it creates stability in the organism for smooth functioning, growth, and reproduction of its members, cells or whole animals.
Homeostasis resembles hysteresis, which is the memory in a material or organism of its shape and condition and the tendency to return to that condition. So when the wind blows on a tree branch, the branch returns to where it was or it may break. But it needs to return to its position in the tree so it can be nourished, grow, and bear seeds.
Living things require stability which they get from homeostatic loops. Plants seek static stability; animals have harness dynamic stability, that is equilibrium and control in motion and change.
The whole earth, Gaia, operates with various homeostatic loops. When temperatures rise, the oceans produce more clouds which obscure the sun and lower heat levels. Life on earth flourishes only when temperatures stay within certain bounds. Once, millions of years ago temperatures dropped and glaciers covered all of earth; life survived in the oceans. Other periods also occurred when heat baked the land bringing drought and hardship to many land animals.
We don’t know how far the current planetary warming will go. Will we have runaway rising temperatures, followed by widespread extinction of species? The outcome depends on how we respond to the problem of carbon emissions and other greenhouse gases that we release with our machines and agriculture. To me, what our response should be is clear: we cannot afford the chance of runaway warming of our planet.
Similarly, we need to be ready for a comet hitting the earth with catastrophic consequences. It happened about fifty million years ago resulting in the extinction of large dinosaurs. Comets follow highly eccentric orbits around the solar system and return periodically to our vicinity. We need to keep these cycles under constant observation and have the rockets and other tools ready to change the direction of a comet which is to impact the Earth.
The cycles of global armed conflict also need to stop if we’re to survive in an age of nuclear weapons.
Our direction to prevent such disasters must be constant with the power of international organizations, such as an empowered United Nations.
In mechanical systems we employ gyroscopes to maintain direction in spite of external forces. Some birds apparently navigate to their destinations North or South using a biological gyroscope or compass. Some humans have a high sense of direction, even without instruments, and they guide others in expeditions and adventures. Talented leaders also exist who can direct humankind to a good destination with proper feedback controls.
Positive or negative feedback puts a closed system into sinusoidal oscillations. Positive feedback, increasing the stimulus, raises the amplitude of the wave, sometimes to unsustainable levels, causing the system to break down. A famous such case was the Tacoma Narrows Bridge in Washington state, which oscillated under the force of winds to such a high resonance that it tore apart. A trained voice can break a glass in a similar fashion.
Negative feedback, cutting back on the input, reduces the amplitude of waves and maintains stability at a lower energy level in the system, occasionally damping it down to inactivity. Certain levels of positive and negative feedback can power standing waves, such as those of musical notes.
A cloud of electrons around the nucleus gives an atom solidity and size, but practically no mass, which is mainly in the nucleus. The electrons are in stable standing waves at specific distances from the nucleus. Without the electron cloud, atoms and matter would shrink to almost nothing.
All matter is energy bound up in stable patterns. When these bundles of energy break up, electromagnetic radiation is released in space at the speed of light, 186,000 miles per second. One description of this phenomenon is Einstein’s equation which balances energy with mass: E = mc².
Everywhere in nature we observe negative feedback loops for homeostasis. The output of the system is made up of oscillations or vibrations, sinusoidal waves of energy. The angle of the wave grows positively for 180 degrees, then negatively180 degrees, in a circle. Thus many natural systems are circular.
Our entire universe is circular in space-time. It expands for billions of years, then it contracts. Strings, not observed but they explain much, the tiniest things in the universe, are vibrating periodically to produce every particle in existence, including the graviton mediating gravity waves, recently observed, and the zoticon, the particle that I have postulated as mediating life, which I call the fifth force.
Many sages believe life itself is circular with birth, death, then rebirth in a different form perhaps; therefore, life is an essentially homeostatic system, allowing for change in form and evolution to a higher-order existence.
In the mental sphere, cycles occur for action or rest, enthusiasm or tranquility. Millions of people in the country suffer from periodic manic behavior followed by depression. A mild form of this complaint is today referred to as cyclothymia, that is mood cycles. Again this fluctuation in energy and mood is due to excessive positive or negative feedback in the brain.
Although medicines are prescribed to control mood cycles, the patient is better off becoming aware of the problem and applying negative or positive feedback to thinking and behavior to smooth out the cycle.
On the onset of the up cycle, the patient should limit activity, instead of indulging in it with euphoria. When the downward feeling comes, one should take some stimulants and get active. Thus the peaks and valleys of mood and energy can be smoothed out. Artistic individuals tend to experience mood cycles, because they are more sensitive than the rest of us.
Tchaikovsky, the Russian composer, and Vincent van Gogh, the Dutch painter, were both afflicted with manic depression.
Finding homeostasis is an urgent need for all of us in order to be happy and successful. We should always maintain our balance and composure, physical and mental, and return to our state of equilibrium when disasters shock our lives, sometimes unexpectedly. Doing otherwise will invite temporary or permanent illness.
Many of us turn to religion to find peace, tranquility, and restoration of spirit. Others turn to doctors or drugs. Still others consult their favorite philosophers, prose writers, and poets. We seek mental and physical stability to enjoy health, success, and beautiful experiences. The key to successful living is finding homeostasis in our lives in spite of perturbations and cycles and exercising control of our functions within a normal operating range.