The numbers don’t lie: women tend to live longer than men. The average American man will live to age 76, according to the latest CDC figures, while the average woman in America will live to age 81.
And a woman’s extra years tend to be healthy ones. The World Health Organization’s HALE index, which calculates the number of years a man or woman can expect to live without a major disease or injury, finds that American men can look forward to 67 healthy years, while American women will enjoy 70 years of “full heath.”
This male-female lifespan gap is not a new phenomenon; experts have known about it for decades. It’s also not restricted to Americans. “This gender gap in life expectancy is true for all societies, and it is also true for the great apes,” says Dr. Perminder Sachdev, a professor of neuropsychiatry at the University of New South Wales in Australia who has studied human longevity.
Why do women tend to outlive men? Sachdev says there are a few popular theories—some to do with biology, and some to do with behavior.