Humans can grow as old as 135 years if they change the way they think about aging, one author and expert on geriatrics claims.

Rudi Westendorp says people's mindset is the only reason that prevents them from coping with increased life expectancy. He is the author of "Growing Older Without Feeling Old: On Vitality and Ageing."

Susannah Mushatt Jones is the oldest person alive at 116 years old. Westendorp thinks that this record is about to be broken because, he believes, the first person to reach the age of 135 has already been born. He claims that humans are gaining six hours in life expectancy every day, and he expects this to continue.

Westendorp, a geriatric medicine professor at the University of Copenhagen, says that over the past 100 years, our life expectancy has doubled from 40 years to 80. People, however, do not know how to adapt to the changes.

Most of us believe that our bodies will eventually deteriorate, he says, urging us to change our lifestyle by the time we reach 50. For Westendorp, people fail to grasp the notion that we can live longer. As a result, we limit and refrain from enjoying life to the fullest.

"They believe that when the maximum number of bends or heartbeats has been reached, it's over, the organ is broken, the body is sick and the person dies," says Westendorp.

Older people pass on their own habits, beliefs and expectations to their children, and these can greatly influence how the younger generations live their lives.

Beliefs about what the body can and cannot do at a certain age and their views about retirement and pensions are outdated, the author notes. Such notions emerged when lifespans were significantly shorter.

"It's wrong to think we can take the life stories of our parents and grandparents as a blueprint for the way our own lives should unfold," he points out.

"Who brings their children up in the realistic expectation that they will reach the age of 100?"

Westendorp encourages people to continually enjoy living healthy social lives. He said lonely, elderly people are most likely to die earlier than smokers. We should alter the way we think about aging: after all, aging is all in the mind, he says.