ABSTRACT
In the modern world much has changed over the last 50 years. Lifestyles have become healthier with emphasis on regular exercise, healthy diets, and a declining dependence on tobacco. As a result, life expectancy has also changed, rising slowly but in a steady manner year after year. In the Western world, the average lifespan is 73.7 years for men and 83.8 years for women. People of both sexes live longer, but every year women have outpaced men. Life expectancy is roughly 7 years longer for women than for men. Although women live longer than men, they do so with greater time spent with disability. This chapter will examine the biologic reasons why women outlive men.
