In many of these “explanations” of floatation we have been dealing with the nebulous borderline between mind and body. The singular experience of floating in an enclosed tank does certain measurable things to your body, which in turn influences your state of mind; likewise, the tank experience has noticeable effects on your state of mind, which can produce numerous changes in your body. Which comes first? The answer to this chicken and egg problem, of course, is that neither exists without the other; they are not separate systems at all, but one system, united in a relationship of balance and interaction.
The first scientist to develop a convincing model of this interaction between psyche and soma was Walter B. Cannon, of Harvard Medical School, in his influential book The Wisdom of the Body, published in 1932.44 One of Cannon’s central ideas was that the body has an inherent “wisdom,” which consists of an exquisitely sensitive self-monitoring and self-regulating system centered in the hypothalamus that is constantly working to maintain the body in an optimal state of balance, harmony, equilibrium, stability. This optimal state, in which all parts and systems are interacting properly, is called homeostasis.
Since the body is always changing, and having to deal with changing conditions, any mechanism to keep the body in equilibrium must be able to maintain stability in the midst of flux, must respond with infinite adaptability to a constantly changing environment. Think of trying to carry a full cup of hot coffee across the rolling deck of a storm-tossed ship—what is required is flexibility and the ability to accommodate one’s direction and attitude to any sudden alteration in the environment. In other words, homeostasis is relative: a process rather than a predetermined state. If we placed a subject in icy water, we might conclude that the body maintained homeostasis by keeping the body temperature very high. But if we placed that same subject in a sauna, we would have to conclude that homeostasis involved various mechanisms such as sweating that let the body disperse heat. Homeostasis, however, is neither “keeping body temperature high” nor “dispersing body heat”; it is the mechanism that responds to heat, cold, or any other conditions the body might have to operate under.
This marvelous instinctual maintenance of the integrity of the whole human system has been compared to a series of feedback loops. Like the simple house thermostat that turns off when the temperature reaches a certain level and switches on when the temperature falls below another level, the body is constantly monitoring and responding to body temperatures, levels of blood sugar, oxygen, salt, and so on. The most refined examples of biological homeostasis are the exquisitely sensitive feedback loops of the endocrine system. The main control center of the endocrine system is the hypothalamus, which ceaselessly tests the level of numerous chemicals in the blood and responds to any imbalance by signaling the pituitary to secrete hormones to correct it.
Within this section we have briefly explored a number of quite different approaches to floating. While each successfully “explains” some of the remarkable effects of floating, none of them purports to offer an overriding theory, a superordinate explanation of exactly how and why floating works. None of these explanations, that is, is the explanation. However, when we see them not as competing theories but rather as integral parts of a single system—parts that interact synergistically, dynamically, to create a whole that is greater than the sum of the parts — we begin to perceive the real nature of the unified-field theory of floating. Taken together, I think these various explanations constitute a sort of body, with its own type of homeostasis.
Homeostasis and Stress. The concept of homeostasis offers not just a way of looking at the relationship among the various approaches to a study of floating; homeostasis is in fact the underlying factor in all the explanations, an in-woven thread uniting each of the explanations. In The Relaxation Response Explanation, for example, we saw how floating can counteract a pathological arousal of the sympathetic nervous system by bringing into play a balancing, compensatory force, the parasympathetic response. Stress is seen as the external influence that the body must respond to, the relaxation response as the force which maintains or restores homeostasis.
Like all homeostatic mechanisms, however, the relaxation response is not good in itself, but only as a means of maintaining the body’s optimal state. As with blood sugar or adrenaline, too much is just as harmful as too little, and excessive dominance of the parasympathetic system can manifest itself as, for example, pathological depression. Phil Nuernberger, director of biofeedback therapy at the Minneapolis Clinic of Psychiatry and Neurology, calls this overdominance of parasympathetic activity The Possum Response. When faced with a threatening situation, people who have an overactive parasympathetic response don’t prepare to fight or run away; “they just sort of roll over and play dead. Their response to fear is not arousal, but inhibition. This is marked by the typical characteristics of extreme parasympathetic discharge—decreased physiological functioning, loss of skeletal tone, mental lassitude, inactivity, and eventual depression.”173 As Nuernberger points out, this imbalance can be as harmful as chronic hyperarousal of the fight-or-flight response. Depression is a causative factor in many illnesses. That is, the helplessness and hopelessness of depression can be just as stressful as chronic hyperarousal.
This brings us to an interesting view of stress: Rather than considering it simply as a hyperarousal of our fight-or-flight response, it is better understood as a state of unbalance, a disruption of our internal equilibrium—that is, a disturbance of our homeostasis. And the theory of stress as interruption, discussed earlier—that stress results from discrepancies between expectations and reality—can now be seen as a psychological equivalent of the disruption of homeostasis. Homeostasis is what our body “expects,” it is the norm; when this norm is interrupted, when the world of our body becomes not the way it was, then we experience stress.
In the case of the sympathetic and parasympathetic responses, the floatation tank seems to counteract stress by maintaining homeostasis. As we saw in the chapter on flow, one characteristic of floating is that it tends to increase the floater’s sense of confidence, capability, and power. That is, it seems to help people overcome depression by counteracting their excessive parasympathetic or possum response. It also seems to work against overactivation of the parasympathetic response by causing the body to release certain natural antidepressant and euphoria-causing neurochemicals, such as the endorphins. At the same time, floating powerfully reduces overactivation of the sympathetic, fight-or-flight response. Floatation seems to work not simply as a consistent counterbalance to the fight-or-flight response on the one hand, or to the possum response on the other, but as a balancing force between both—a maintainer of homeostasis.
This same observation holds true in many other of the explanations I have offered. We saw that floatation tends to work on our chronic imbalance between right hemisphere and left, not by simply shifting the dominance to the minor hemisphere but by bringing the imbalanced right and left hemispheres into a state of symmetry and synchrony in which the entire apparatus of the brain is unified and works in harmony—that is, hemispheric homeostasis.
While not enough research has been done yet on the effects of floatation on our biochemicals, what we do know indicates that floating’s beneficial effects can be attributed not to some constant and unvarying relationship between floating and, say, serotonin, but to its power in allowing the body to establish a homeostatic balance. Medical researchers Fine and Turner of the Medical College of Ohio reached a similar conclusion when trying to understand how short periods of floatation could have such significant long-term effects on numerous hormones and other body functions such as blood pressure. “In light of the carry-over effect” of the floating on the hormone levels, they concluded that repeated floating “could alter the set-points or baselines of the endocrine homeostatic mechanisms.”252
Homeostasis seems to be the principle at work in most of the observed effects of floating. Even things like spontaneous reduction in smoking or addictive behavior can be seen as the body’s natural tendency to restore itself to its optimal state.
Why is the tank so effective in fostering homeostasis? If we see the mind/body as a single system, then it becomes clear that external stimuli are constantly militating against the system’s equilibrium: Every noise, every degree of temperature above or below the body’s optimal level, every encounter with other people, every feeling of responsibility, guilt, desire—everything we see and feel is incessantly interrupting, impinging on our self-contained system, causing it to expend energy to maintain its homeostatic balance. But when we enter the tank, our environment abruptly stops its constant alteration. The system is for once able to experience itself as a single, integral, unified entity. Since there are no external threats, no need to adapt to outside events, no deviations from the expected, the system can devote all its energies to restoring itself. It is as if we said Time out to the game of life, allowing our bodies to take a breather and restore themselves to normal. The normal state, of course, is health, vigor, enthusiasm, and immense pleasure in being alive. The way the body gets there, and stays there, is homeostasis.