Korean scientists have found one possible way for men to extend their lifespan, though it’s doubtful most would take it. It turns out that eunuchs living in Korea centuries ago lived significantly longer than other men, according to historical data.

The finding seems to support theories that male sex hormones contribute to a shorter lifespan, three researchers from Inha University, Korea University and the National Institute of Korean History wrote in a paper published in the journal Current Biology.

Eunuchs in Korea, called naesi, enjoyed a special status as servants to the royal family and as bodyguards to the king and his harem. Male eunuchs were either castrated accidentally -- sometimes after being injured by dogs -- or on purpose, as a quick way to move up in the world. They could marry and adopt girls or castrated boys.

The trio of researchers examined records kept in a genealogical document called the "Yang-Se-Gye-Bo." The record, penned in 1805, records birth and death dates and other information for 385 eunuchs. The team was able to figure out the lifespans for 81 of those men.

On average, eunuchs lived to about 70 years of age, which is between 14 and 19 years longer than the lifespan of noncastrated men of the same social standing. Three of the 81 eunuchs cracked 100 years of age.

But perhaps the eunuchs lived longer because they were pampered palace-dwellers? Not so, the researchers say.

“Except for a few eunuchs, most lived outside the palace and spent time inside the palace only when they were on duty,” the team wrote.

Plus, the average lifespan of male Korean royalty at the time was between 45 and 47 years, according to the paper.

“Our study supports the idea that male sex hormones decrease the lifespan in men,” the authors said.

There are many theories for how sex hormones can contribute to heart disease and weaken immune system function in men, but no solid answers just yet.

Some researchers once thought that testosterone was a primary factor in the hardening of arteries, but there’s little evidence to support this link. The true influence of hormones on male lifespan turns out to be much more complex.

Both male and female sex hormones are thought to play some role in modulating heart function, but men seem to be adversely affected by certain hormones that benefit women. A 2008 paper in the journal Atherosclerosis linked higher levels of the estrogens estradiol and estrone, which are known to promote heart health in women, to increased levels of bad cholesterol and low levels of good cholesterol in men. This “male disadvantage” in heart disease is dire -- in the U.S., it accounted for more than a quarter of all the deaths of men that died in the year 2006, according to the U.S. Centers for Disease Control.

It’s not yet certain that castration results in longer life. While one study in 1969 found that castrated men in mental institutions lived longer than noncastrated institutionalized men, another paper that examined biographies of opera singers found that the castrati, who were cut before puberty, did not generally live longer than intact male singers.

Still, "for better health and longevity, stay away from stresses and learn what you can from women,” authors Kyung-Jin Min and Cheol-Koo Lee joked in a statement Monday.

SOURCE: Min et al. “The lifespan of Korean eunuchs.” Current Biology 22 published online 24 September 2012.