The Biology of Human Survival: Life and Death in Extreme Environments

  • Claude A. Piantadosi
Oxford University Press: 2003. 280 pp. £24.95, $35
Into the depths: the body can muster an extraordinary range of defences against extreme conditions. Credit: JEFFREY L. ROTMAN/CORBIS

Stories of human achievements and survival against the odds have always been fascinating. Whether in the context of simply living in the world's harshest environments, mounting expeditions to its hottest, coldest, highest or deepest places, or coping with the aftermath of disaster, everybody wonders at just how the body copes. Answers lie in the study of environmental physiology, the responses and adaptations that can take men and women to extremes.

The Biology of Human Survival is an extraordinary environmental physiology text. The topics covered range far beyond biology to include the physics and function of artificial aids that allow humans to cope with extremely hostile environments. But engineering approaches are not just used to describe life-supporting technologies — the author also uses them to explain biological concepts. This approach helped me to understand some concepts that I had previously struggled with. Occasionally, however, the opposite applies.

The book begins by describing the limits to the range of environments that can support human life, along with the principles of survival, adaptation and life-support systems. The historical background to environmental physiology is fascinating, but as the book moves on to adaptation (physiological changes in response to environmental stress) and maladaption (adverse changes resulting from adaptation), some topics were unclear and others were made unnecessarily complex. For example, the author stresses the importance of discriminating between technical definitions, such as adaptation, acclimatization, acclimation, accommodation and habituation, but then, I feel, blurs the boundaries. He has also focused particularly on maladaption and cross-acclimation (adaptive changes to one type of environmental stress that prove beneficial during exposure to stress from a different type of environment), perhaps ascribing more importance to these processes than they deserve. Indeed, he suggests that adverse effects of cross-acclimation between cold and hypoxic responses contribute to the difficulty of climbing Mount Everest in winter. In reality, this must be insignificant compared to winter's cold, storms and jet-stream winds.

But back to the book's strengths. Several chapters cover adaptation to heat and cold in detail. There are lengthy descriptions of human responses and adaptation to icy environments, but our physiological responses to heat (which are far more effective than those to cold) are not covered in such depth. This book is not, then, a definitive work on environmental physiology. But viewed as a collection of thought-provoking pieces about this field it becomes a tour de force. This is especially true when the author strays from his title, covering not just engineering and biology, but also life that is far from human. The piece on the physiology of the camel in the section on salt and water is masterly, and there are fascinating descriptions of the interaction between primitive life and Earth's early atmosphere. There is also a beautifully worked analysis of why you should never drink sea water.

The chapter on nutrition and survival, although generally excellent, does perpetuate some rather outdated views. For example, it states that the main difference between the forms of malnutrition known as marasmus and kwashiorkor is in the level of protein intake; elsewhere in the book, the author mentions the more current idea that kwashiorkor and its accompanying oedema are more a product of free-radical membrane damage than low protein ingestion. There is also misleading information about the subsequent reintroduction of normal nutrition (refeeding), and there are some rather simplistic views on vitamin deficiency. These include the idea that the main problem with vitamin A depletion is ocular, whereas we now know that vitamin A deficiency also impairs responses to infections of the gut and respiratory tract, leading to deaths in people who have very little or no eye damage.

Biology and engineering are mixed even more freely in the second half of the book than in the first. Descriptions of the technical engineering solutions to the high pressures of the deep sea and low pressures of the high mountains are balanced excellently with descriptions of pressure physiology and the illnesses that can stem from pressure change. Just as in the earlier part of the book, in which problems caused by the cold are illustrated by compelling tales including those of Scott of the Antarctic and the Titanic, the author uses famous disasters to bring the issues in this section to life. The sinking of the Russian submarine Kursk is used to great effect.

Towards the end of the book there is a surprising but topical diversion into survival in the face of nuclear, biological and chemical weapons of mass destruction. This is a rather depressing digression, but it is both interesting and relevant.

The book ends with a section lifting us away from Earth's limitations to describe the exciting physiology and engineering of high-performance aircraft and space flight. The final chapter even speculates on the requirements for and limitations to future human colonization of other planets, and so ends on a positive note, as will I. There is no doubt that this book will be enjoyed widely and will be much appreciated by both specialists and scientifically thoughtful lay readers.