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How human beings have adapted to a wide range of stressful environments – extreme temperatures, solar radiation, high altitudes, and nutritional stress – has been the subject of much research in recent years by psychologists, biologists, and physical anthropologists. Here for the first time Dr. Frisancho presents in a single volume knowledge on human adaptation that has previously been widely scattered and highly specialized. He examines from physiological and anthropological perspectives the short- and long-term reactions of the human body to various environmental stresses. Based on research that has been done in the laboratory and from studies of native populations living in stressful environments, Dr. Frisancho discusses the effects of extreme heat and cold, solar radiation and the selective value of skin pigmentation, high altitude hypoxia, growth in high altitude populations, diseases related to life in high altitudes, diseases and effects of undernourishment, and disease and the westernization of diet. This work is a valuable and much needed introduction to the field of human adaptation.
 
 

Since Pavlov, physiologists have explained homeostasis—the regulation of bodily functions—as the action of fixed negative feedback networks within individual organ systems. However, these standard explanations largely ignore the mechanisms of conditioning and learning. Drawing on the work of Western, East European, and Russian physiologists, Barry R. Dworkin challenges traditional concepts and argues that learning mechanisms of the nervous system are essential to regulation. Dworkin shows how, through experience, learning mechanisms determine dynamic stability and the long-term regulation of heart rate, blood pressure, glucose, electrolytes, and temperature. He argues that "hard wired" mechanisms do not adequately account for the speed and accuracy of physiological adjustments, and supports his contention with detailed analyses and mathematical models of how conditioned and unconditioned reflexes interact. Dworkin reviews a wealth of research on interoceptive conditioning, conditioned drug responses, and visceral adjustment. Combining physiological and behavioral data with mathematical analysis and computer models, he synthesizes the work of Pavlov and W. B. Cannon in a quantitative theory of physiological regulation that will interest researchers and theorists in medicine, physiology, neuroscience, and biopsychology.

'Complete freedom from disease and from struggle is almost incompatible with the process of living, ' Rene Dubos asserted in this classic essay on ecology and health. All the accomplishments of science and technology, he argued, will not bring the utopian dream of universal well-being, because they ignore the dynamic process of adaptation to a constantly changing environment that every living organism must face.