Longevity

The average life span of Americans has been increasing dramatically since the industrial revolution. However, most of the gains resulted from decreasing childhood mortality. The maximum life span--about 125 yr for women and somewhat shorter for men--has changed little in recorded history, although some experts suggest that it may be slowly increasing.

Several factors influence longevity. Heredity affects longevity primarily by influencing whether a person will contract a disease. Inheriting a propensity to hypercholesterolemia is likely to result in a short life, whereas inheriting genes that protect against coronary artery disease and cancer helps ensure a long life. Medical treatment contributes to increased survival after diseases are contracted, especially when diseases (eg, infectious diseases, some cancers) are curable. Another important influence on longevity is lifestyle. Not smoking, maintaining a healthy weight and diet, and exercising appropriately help people avoid disease. Similarly, some lifestyle choices help prevent injury. Exposure to environmental toxins can shorten life span even among people with the most robust genetic makeup.

This topic was last updated June 2006.