The Biology of Infrared Radiation

Much has been written about the physiological significance of infrared radiation from human beings and other warm blooded animals. Nevertheless, there is still no unified theory accounting for that infrared radiation in terms of its meaning in the context of physiological activity and system metabolism. Our intention in this monograph is to present a unified theory accounting for the observations of infrared radiation from warm blooded animals and provide a guide for interpretation of these observations in a clinical context. It was a work in progress until the untimely death of neurologist and infrared imaging pioneer, Jacob Green, MD, PhD.

We can be reasonably sure that the metabolic processes of individual animal cells, and probably, plant cells as well, typically release heat and may therefore be considered “exothermic.” Groups of cells associated for a common purpose as tissues also generate heat both by the metabolic activity of each individual cell and the physiological activity of the groups of cells acting as a tissue.

The tissues which aggregate to form an organ also radiate infrared energy as a result of the physiological processes they perform within an organism. Every warm blooded organism, ranging in size from whale to shrew (including human beings and other primates) radiates infrared energy constantly from their largest organ, the skin.

The infrared energy radiated by the skin and under appropriate circumstances, absorbed by the skin, apparently acts to maintain core body temperature which in human beings is 98.6° Fahrenheit or 22.7° Celsius. Core body temperature in warm blooded animals is intimately associated with homeostasis (physiological equilibrium). One of the great questions of physiology is just what the terms of that relationship are. Another question is the mechanism whereby radiation or absorption of infrared energy affects homeostasis in the entire organism (biosystem)

The Skin

Available evidence indicates that there are functional units of the skin that are directly involved with the absorption and radiation of infrared energy. These dermal units consist of cells and their associated microvasculature together with unmyelinated sympathetic nerve fibers which apparently provide information to the microvasculature and regulate the rate of blood flow and accumulation of blood in each of these dermal infrared radiating units. Associations of these dermal infrared radiating units are generally referred to as thermatomes by way of analogy with dermatomes which are areas of the skin which seem to communicate with the central nervous system.

Another question which requires an answer before any coherent theory associating physiological activity and system metabolism with infrared radiation from the skin is just how the sympathetic nervous system which seems to regulate the microvascular activity of dermal infrared radiating units of the skin and which conducts information at the rate of approximately five meters per second, can control microvascular activity at speeds which appear to be more consistent with central nervous systems conduction velocities which are approximately twenty meters per second.

Homeostasis and microcirculatory processes

The evidence seems to support the theory that the homeostasis represented by a relatively stable core body temperature among warm blooded animals is a result of the activity of microcirculatory processes near the surface of the skin. These microcirculatory processes appear to be under sympathetic nervous system control.

Until high resolution dynamic digital infrared imaging became commercially available, the theory was that somehow information about the core body temperature was transmitted by the sympathetic nervous system to the capillary circulation of the skin and that the skin would either increase the rate at which it radiated infrared energy or shut down the radiation process so as to conserve core body heat.

While that theory certainly comports with the observations that exogenous application of heat or cold produces greater or lesser infrared radiation from the surface of the skin, it does not account for anomalous conditions such as reflex sympathetic dystrophy (now renamed chronic regional pain syndrome) where a particular area of the body may radiate considerably less infrared energy than other areas with no apparent anatomical connection between the radiation process and whatever underlying patho-physiological process is occurring.

The early observations that established simple one-to-one relationships between heating and cooling and infrared radiation are insufficient to account for the wealth of data that is being acquired every day through high resolution dynamic digital infrared imaging.

The obvious fact that infrared radiation from the dermal infrared radiating units of the skin varies rapidly over time and skin surface is both significant and perplexing.

Any theory which purports to explain the relationship between physiological processes in warm blooded animals and infrared radiation from the skin of those animals must account for that constant change in the rates and pattern of infrared radiation from the skin.

A more recent model

Recent advances in nonlinear dynamics, chaos theory, control theory, and stability theory as well as the continued development of General Systems Theory provide an immediate model for this kind of rapidly fluctuating system the purpose of which seems to be maintaining some sort of dynamic equilibrium which in physiology is generally referred to as homeostasis. That model is the high performance aircraft where control surfaces must vary constantly in real time in order to maintain flight stability.

Just as the control surfaces of that modern high performance plane are constantly changing in response to both exogenous environmental conditions and endogenous conditions which are both under the pilot’s control such as maneuvering the aircraft for a specific purpose, and outside the pilot’s control, such as the functions of the engine, so the infrared radiating energy from the skin of a warm blooded animal changes constantly in response to both exogenous and endogenous conditions and stimuli.

Anatomical studies indicate that the skin of warm blooded animals consist of a number of cell types organized into and about micro vascular units innervated by unmyelinated sympathetic nerve fibers and under sympathetic nervous system control. There are also areas of the skin which are innervated by units of the central nervous system as well.

Each unit of skin surface and its associated micro vasculature and sympathetic nervous system control unit is capable of radiating infrared energy and in appropriate cases, absorbing infrared energy.

The mechanism seems to be variation in the rate of flow in the microvasculature of each skin unit.

Interpreting patterns of infrared dermal radiation

One of the puzzles that is associated with attempts to interpret patterns of infrared radiation from animal skin is that the rate of transmission of information along the unmyelinated fibers of the sympathetic nervous system which seem to control the rate of infrared radiation from the skin is only approximately five meters per second (compared to the rate of information transferred along the myelinated fibers of the central nervous system which is upwards of forty meters per second) yet dramatic changes in infrared radiation reflecting significant alterations in circulation of the microvasculature associated with particular thermally active skin areas or thermatomes, is much faster than sympathetic nerve fiber transmission of information would support.

High resolution dynamic digital infrared imaging studies support the observation that each dermal unit radiates individually and often independently of all other units, including its immediate neighbors. What can that mean?

The Skin as an Antenna Field

In looking for physical models of physiological processes, the basic rule of physical science that the least complicated explanation is often the closest to reality (the test of Occam’s Razor) leads immediately to consideration of the skin as an antenna field of individual active elements—the dermal units capable of radiating infrared energy, and their supporting microvasculature and sympathetic control system.

Utilizing that kind of model, it appears that the sympathetic fibers associated with control of the microvasculature of each infrared radiating unit are part of some kind of feedback loop that provides positive and negative feedback information to some underlying and deeper physiological process or metabolic system.

If the antenna field model is accurate, then the questions arise about connections.

How is the information transmitted or transferred to the infrared radiating unit from wherever it arises? And equally troubling, “What physiological processes or aspects of system metabolism are actually reflected in the infrared radiation transmitted from each infrared radiating unit?”

More. . .