This volume is about how humans respond acutely to, adapt, and sometimes fail to adapt to high altitude, in particular to the hypoxia of high altitude' ' (p. v). This book authoritatively addresses a huge range of topics relevant to general questions about adaptation and about what various organ systems can do to maintain homeostasis. It is a lot of fun to read.
This edited volume with 45 authors and 25 chapters starts off with Chapter 1 by Charles S. Houston, The Growth of Knowledge about, Air, Breathing, and Circulation as They Relate to Altitude.'' This fascinating history describes the realization of the distinctiveness of mountain air, the discovery of the composition of air, animals' need for oxygen, the physiology of oxygen delivery, and the relationship between oxygen and mountain sickness. Chapters 2 and 3 set the broader perspective with discussions of The Atmosphere'' by J.B. West and ``The People'' by S. Niermeyer, S. Zamudio, and L.G. Moore. West describes the evolution of the atmosphere, the relationship between altitude and barometric pressure, environmental factors covarying with altitude and artificial atmospheres at high altitudes. Niermeyer and co-workers present a view of the history of permanent human habitation of high-altitude environments and of high-altitude adaptation across the life cycle. These chapters set the stage for subsequent chapters dealing with physiology and remind the reader to consider barometric pressure, population of origin, and stage of the life cycle.
Chapters 4 and 5 address cellular and molecular mechanisms of oxygen sensing and molecular defenses. S. Lahiri and N.S. Cherniack summarize oxygen sensing in the arterial chemoreceptors and P.W. Hochachka offers a comparative perspective from hypoxia-tolerant turtles. These chapters summarize the authors' work up to about 1995. However, they do not reflect the explosion of knowledge about the in-fluences of hypoxia on gene expression in the past 10 years. Readers will want to consult the exciting work of G.L. Semenza (e.g., 2001) and others dealing with the transcription factor called hypoxia inducible factor 1 (HIF1) and the dozens of genes induced by HIF1. This fast-moving area of research offers the potential to integrate understanding of human adaptation to high altitude from oxygen sensing and response at the genetic and molecular levels to the physiological, the organism, and the population levels.
Chapters 6--21 address specific physiological topics and systems such as the control of breathing (C.A. Smith, J.A. Dempsey, and T.F. Hornbein), the mechanics of breathing (J. Milic-Emili, B. Kayser, and H. Gautier), gas exchange (P.D. Wagner), the cardiovascular system (E.E. Wolfel and B.D. Levine), the pulmonary circulation (J.T. Reeves and K.R. Stenmark), the cerebral circulation (J.W. Severinghaus), the brain (M.E. Raichle and T.F. Hornbein), the autonomic nervous system (D.R. Seals, P.P. Jones, and K.P. Davy), skeletal muscle (H.J. Green and J.R. Sutton), blood (R.F. Grover and P. Bartsch), renal function (E.R. Swenson), metabolism (G.A. Brooks and G.E. Butterfield), the endocrine system (J.-P. Richalet), immune responsiveness (R.T. Meehan, P.N. Uchakin, and C.F. Sams), exercise (R. Roach and B. Kayser), and sleep (J.V. Weil and D.P. White). Some chapters (for example, those on the immune system and autonomic nervous system function at high altitude) are brief summaries of scant evidence, along with suggestions for further work. Other chapters (for example those on the heart and the systemic and pulmonary circulations) are lengthy analyses of decades of accumulated evidence, along with discussions of key unanswered questions.
Chapters 22--25 describe failures to adapt to high-altitude hypoxia. These are Acute Mountain Sickness and High-Altitude Cerebral Edema (P. Bartsch and R. Roach with Diana Depla), High-Altitude Pulmonary Edema (R.B. Schoene, H.N. Hultgren, and E.R. Swenson), Chronic Mountain Sickness (C.C. Monge, F. Leon-Velarde, and A. Arrequi), and High Altitude and Common Medical Conditions (P.H. Hackett). Surprisingly little is known about predicting individual risk of these conditions and about their mechanisms.