The Enigma of Aging

Abstract

Do we age because our tissues become increasingly worn out? This book comprehensively dismisses this idea, and provides a fresh perspective on the science and philosophy of aging. In a carefully argued work, the authors describe how lifespan is an intrinsic feature of each species, and put forwards the idea that aging has evolved as an adaptation for the benefit of the group. The authors describe the historical background and focus on the different theories, often conflicting. A key proposal is that a lifetime clock is located in the central nervous system; it signals via the blood and determines the rate of aging and timing of demise. Drawing on studies in multiple species, they discuss the circulating factors that are involved in this process, and suggest that the primary targets of the clock are stem cells whose rates of renewal dwindle with age, which in turn impacts most acutely on the immune system. As a consequence, they argue that the majority of age-related conditions, including disorders such as Alzheimer’s disease, are ultimately triggered by infection. They describe attempts over the centuries to defer aging, some of which presage current thinking, and review the biomedical and lifestyle options that are available to counter the onset of age-related disorders. In the final chapters they discuss the profound ethical issues that bids to develop new anti-aging treatments will surely engender. This book is a must read for everyone with a serious interest in one of the key questions and challenges of our time.