"If oxygen is withheld from tissues of a higher organism for a longer period, death follows. If, however, oxygen is withheld but periodically, as in the experiments of Cameron and Goldblatt, and restored before death ensues, then we can expect no only that the oxidative system will become disorganized but also that there will be degeneration of all those higher functions and regulation which demands structure and a perturbed electromagnetic field for their function and energization. The cell will thus revert to a more primitive way of life with its lower level of organization, which is not dependent on ordered structures, which also lacks the subtle regulations and has thus (as in yeast) unlimited proliferation as one of its characteristics, and can depend for its energy supply only on fermentation."
"We recognize life by its actions; motion is one of them. Quo cicior motus, eo magis motus, the faster a motion, the more of a motion it is. The more life does, the more life it is; the more negative entropy is liberated, the more can be retained of it. Life supports life, function builds structure, and structure produces function. Once the function ceases the structure collapses, it maintains itself by working. A good working order is thus the most stable state."
"A living cell requires energy not only for all of its functions, but also for maintenance of its structure."
"Treating humans without concept of energy is treating dead matter."
"The role of ATP is not limited to the contraction cycle. It dominates the physical state of muscle even in rest, keeping it soft and pliable, keeping actomyosin dissociated. I have shown, with Borbiro, that rigor mortis is but a lack of ATP..."
—The Living State by Albert Szent-Györgyi (1972)
"One method for the destruction of the respiration of body cells is removal of oxygen. If, for example, embryonal tissue is exposed to an oxygen deficiency for some hours and then is placed in oxygen again, 50 percent or more of the respiration is usually destroyed. The cause of this destruction of respiration is lack of energy. As a matter of fact, the cells need their respiratory energy to preserve their structure, and if respiration is inhibited, both structure and respiration disappear. Another method for destroying respiration is to use respiratory poisons. From the standpoint of energy, this method comes to the same result as the first method. No matter whether oxygen is withdrawn from the cell or whether the oxygen is prevented from reacting by a poison, the result is the same in both cases-namely, impairment of respiration from lack of energy."
— On The Origin of Cancer Cells by Otto Warburg (1956)
“A point made by Otto Warburg and Albert Szent-Györgyi and others is that there is an important difference between the energy provided by glycolysis and that provided by mitochondrial respiration. They felt that glycolysis was a more primitive form of energy production, and supported only primitive function and cell division, while the more efficient respiration supported cell differentiation and complex functioning.”
—Generative Energy by Raymond Peat (1994)
"I started my work with progesterone and related hormones in 1968. In papers in Physiological Chemistry and Physics (1971 and 1972) and in my dissertation (University of Oregon, 1972), I outlined my ideas regarding progesterone, and the hormones closely related to it, as protectors of the body's structure and energy against the harmful effects of estrogen, radiation, stress, and lack of oxygen.
The key idea was that energy and structure are interdependent, at every level."
"What could be more important to understand than biological energy? Thought, growth, movement, every philosophical and practical issue involves the nature of biological energy."
"During the bloods movement through the body the oxygen-pressure will decrease to a relatively low value, whereas at the same time the carbon dioxide-pressure rises. This will greatly support the oxygen release from the blood, resulting in an improved efficiency in oxygen usage... The carbon dioxide pressure of the blood is therefore to be regarded as an important factor in the inner respiratory metabolism, which itself can be regulated by it in a very effective way. Furthermore our experiments help to explain different observations on the supporting effect of carbon dioxide in cases of oxygen lack: If one uses carbon dioxide in appropriate amounts, the oxygen uptake of the lungs will not be influenced, whereas the oxygen, that was taken up can be used more effectively throughout the body."
—Concerning a Biologically Important Relationship The Influence of the Carbon Dioxide Content of Blood on its Oxygen Binding by Christian Bohr, et al. (1904)
"Definition and Terminology of Biologic Stress: A great deal of confusion has arisen in lay and even in scientific literature because the term stress means different things to different people. Stress is part of our daily human experience, but it is associated with a great variety of essentially dissimilar problems, such as surgical trauma, burns, emotional arousal, mental or physical effort, fatigue, pain, fear, the need for concentration, the humiliation of frustration, the loss of blood, intoxication with drugs or environmental pollutants, or even with the kind of unexpected success that requires an individual to reformulate his lifestyle. Stress is present in the businessman under constant pressure; in the athlete straining to win a race; in the air-traffic controller who bears continuous responsibility for hundreds of lives; in the husband helplessly watching his wife's slow, painful death from cancer; in a race horse, its jockey and the spectator who bets on them. Medical research has shown that, while all these subjects face quite different problems, they respond with a stereotyped pattern of biochemical, functional and structural changes essentially involved in coping with any type of increased demand upon vital activity, particularly adaptation to new situations. All endogenous or exogenous agents that make such demands are called stressors. Distinguishing between their widely differing specific effects and the common biologic response that they elicit is the key to a proper understanding of biologic stress."
"In fact, we shall see that biologic stress is closely linked to, though not identical with, energy utilization. This explains its apparently paradoxical, yet inseparable combination with the specific effects of the particular agent that creates a need for adaptive work. Any demand made on the body must be for some particular, that is, specific activity and yet is inseparably associated with non-specific phenomena (that is, energy utilization), just as in the inanimate world specific demands made upon machines to increase or decrease room temperature, to produce light or sound, to accelerate or decrease motion are invariably dependent upon energy utilization."
—Stress in Health and Disease by Hans Selye (1976)
"The extraordinarily unstable stuff of which our bodies are constituted is persistently subjected to various external and internal conditions which, if not resisted, would profoundly alter its ability to function."
—Stresses and Strains of Homeostasis by Walter Cannon (1935)