Men don't live as long as women -- but there is something they can do about it.
We all know that in general women live longer than men. The average life expectancy of a male born in the United States today is about 76 years. For a female it's 81. Even before they're born, males are at risk. About 115 males are conceived for each 100 females, but on average only 104 of those males make it into the world, as 11 of them fail to survive to birth.
A study from Australia's Monash University, published in August 2012, suggests a new theory. Researchers studied fruit flies to show how mutations to the DNA of mitochondria accounts for differences in life expectancy for males and females throughout the entire animal kingdom. (As an example, the life expectancy of a male chimpanzee is 45 years, compared to 59 for the female. The average male mosquito lives a week; the female a month.)
The mutations within mitochondrial DNA not only affect how long males live, but the speed at which they age. But the same mutations do not affect aging in females.
Mitochondrial mutations that harm females are screened out when passed down from generation to generation. But mutations are not screened for males. Therefore mutations that will not harm females, but might harm males, pass through from one generation to the next, accumulating for males but leaving females unscathed.
This new study supports what scientists have long known -- that at least some of the difference in longevity between men and women is in their genes. Natural selection favors reproduction over longevity, in essence using the body simply as a vehicle for passing on genes.
Males have shorter lifespans than females because once they pass on their genes, they are
"disposable," according to Tom Kirkwood's, a professor at University of Newcastle, controversial theory. But females are built to stick around to raise the young to maturity -- especially in species like humans who take many years to mature.
A related theory suggests that males compete with one another for the attention of females. The male who proves his mettle by engaging in risky behaviors like hunting and fighting is more likely to attract the female and therefore pass on his genes. But unfortunately for males, the riskier the behavior, the shorter the lifespan.
All this may be true. But scientists estimate that only about 30 percent of the variation in longevity can be attributed to genetics, Tom Perls, founder of the New England Centenarian Study, told Time. The rest depends on environmental factors -- your exposures and your behaviors. So what can men do to increase their life expectancy?
Take fewer risks. Men in their late teens and 20s go through a testosterone surge that tends to produce aggressive and risky behaviors. Young men drive too fast, don't wear their seat belts; they fight and experiment with "deadly weapons," Perls said. Even today, this leads to a higher death rate among young men, as more men than women die in car accidents, as well as other types of accidents and homicides. And we all know that risky behavior doesn't always end when a man turns 30.
Get a safer job. Traditionally, men took on dangerous jobs, from the military to mining, while women filled safer jobs such as teaching, nursing or child care. In our modern times, dangerous jobs have become safer, and the gender gap is closing. Nevertheless, men still work most of the dangerous jobs in America, from fisherman to logger to truck driver.
Don't smoke or drink too much. Men tend to party more than women, and it takes its toll on their health. Fortunately, this gender gap is shrinking, as over the last two decades men have smoked less and less.
Eat a healthier diet. A diet with more fruits and vegetables (which reduces colon cancer) and less red meat (which will reduce risk of both heart disease and cancer) will help men improve their health and extend their life expectancy.
Deal with your stress. Researchers once thought that men suffered more stress because of their demanding jobs. That may no longer be true. But one thing is certain. Men are more likely to internalize their stress, or deal with it in harmful ways, such as drinking or fighting. Men also have higher suicide rates than women. And stress plays an important role in heart disease. So it's crucial for men to find healthy outlets for stress, through sports or counseling or meditating.
Go to the doctor. It's an old joke, but some men out of a false sense of bravado won't go to the doctor, no matter how much it hurts. While it may not be necessary for healthy young males to undergo an annual physical, older men should see their doctor regularly. And make sure to keep up to date with preventative care, from monitoring cholesterol to screening for colon cancer.
One last note: Women shouldn't take a longer life expectancy for granted. The gender gap
has been closing. Between 1989 and 2009, life expectancy increased by 4.6 years for men, but only 2.7 years for women. Let's hope any further narrowing of the gap is not due to women acting like males, but men behaving more like women.