Note to candidates: Being president takes its toll

Being president is not for the faint hearted in more ways than one: It could knock years off your life, according to a new study in the British Medical Journal that found that that the world's leaders tend to age fast and die sooner.

In the study published Monday, Harvard Medical School researchers reported that heads of state or government live up to 4.4 fewer years after their last election than the runners-up who had never served.

"It has been suggested that heads of government experience accelerated aging and premature mortality. Analyzing historical election data from 17 countries spanning more than two centuries, we found that being elected to head of government was associated with a substantive increase in mortality compared with runners-up," Dr. Anupam Jena and colleagues said.

The study set out to determine whether being elected to head of government was associated with accelerated mortality.

The Oval Office.
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The Oval Office.

They studied historical survival data on candidates in parliamentary or presidential elections in 17 countries, including the U.S., U.K., Australia and various European countries from 1722 to 2015.

Looking at 540 candidates (279 winners and 261 runners-up who never served), they studied how long each candidate had lived after the election, relative to what would be expected for an average person of the same age and sex as the candidate during the year of the election.

"We found heads of government had substantially accelerated mortality compared with runner-up candidates. Our findings suggest that elected leaders may indeed age more quickly," the study reported.

Without adjustment for life expectancy at time of last election, elected leaders lived 4.4 fewer years than runners-up.

However, elected leaders were also on average 3.8 years older in the year of their last election compared with runners-up so after adjustment for life expectancy, elected leaders lived 2.7 fewer years than runners-up.

Power and responsibility on a global stage does certainly tend to age people. U.S. President Barack Obama and U.K. Prime Minister David Cameron are noticeably more gray than they were on election to office. Being fit and healthy is often seen as a vote winner. On Monday, Donald Trump released a report from his doctor boasting of the 69-year-old Republican presidential candidate's "extraordinary strength and fitness."

— By CNBC's Holly Ellyatt, follow her on Twitter @HollyEllyatt. Follow CNBC International on Twitter and Facebook.