Who are the world's oldest business executives?

The average age at which North Americans typically retire is around 60 years old. And while many Baby Boomers across Canada and the United States look forward to an early retirement, a growing number of middle-aged people are opting for a never-ending career in fields they love.

Warren BuffettMany of these older workers aren’t just continuing in careers they enjoy; some of them are also prominent leaders in the business world.

This past week, legendary Texas oil man T. Boone Pickens published an article on online business social media networking website LinkedIn coinciding with his 85th birthday, where he wrote that, to him, “retirement is not an option,” and how continuing to travel widely and conduct business meetings around the world are a surefire way to stay healthy and vibrant.

To Pickens, another motivator for his continued career is amassing wealth, although he doesn’t plan on keeping it for himself: “My charitable gifts are now approaching my net worth. That’s an accomplishment I am proud of,” he wrote.

And although Pickens is one of the world’s most high-profile older CEOs, he is by no means the only one.

Another business magnate is 82 year-old Warren Buffett, CEO and Chairman of Berkshire Hathaway and the world’s third-richest person, with a current estimated net worth of about $54 billion (US). Like Pickens, Buffett has made a public commitment to philanthropy, and said he plans on giving 99% of his vast wealth to charity.

“I’m having the time of my life,” Buffett said in a 2012 interview with CNN Money about his business career. But, he added, “In terms of managing money, or even managing a business...age isn't really a deterrent. It's a deterrent to everything else; hand-eye coordination, balance, and all kinds of things.”

As a result, while many older business leaders may not be intending to retire at all, for most people, at some point, the aging body begins to take its toll.

In a 2012 article in the academic journal Modern Biological Theories of Aging, Dr. Kunlin Jin of the University of North Texas wrote that while the modern scientific community is yet to establish a consensus with regards to the primary reason for physical aging among individuals, the aging of the human body remain a universal condition, and this can shorten the career lifespan of older executives.

Despite the challenges of running a business and aging, there remain a number of high-profile business executives over the age of 70, including Les Wexner, CEO of L Brands fashion retailer, Rupert Murdoch, Chairman and CEO of News Corporation, and J.W. Marriott, Chairman of hotel chain Marriott International.