Social contact and regular exercise are key to aging well and living a longer life, according to newly presented research.

In fact, feeling extremely lonely can increase an older person's chances of premature death by 14 percent, an impact nearly as strong as that of a disadvantaged socioeconomic status, according to John Cacioppo, psychology professor at the University of Chicago.

He noted that a meta-analysis of several studies published in 2010 showed that social isolation had twice the impact on the risk of death as obesity.

Cacioppo presented the findings Sunday at an annual conference in Chicago of the American Association for the Advancement of Science.

The research carried out on a group of 20,000 people revealed adverse health effects of feeling alone, including sleep problems, high blood pressure, impaired immune cells and depression.

"Retiring to Florida to live in a warmer climate among strangers is not necessarily a good thing if it means you are disconnected from people who mean the most for you," Cacioppo said.

Often, loneliness is accompanied by a sedentary lifestyle, which can significantly weaken one's health.

Simple exercise such as walking regularly at a good pace can't just cut the risk of cardiovascular and Alzheimer's disease by 50 percent -- it can also clearly slow down the normal aging process of an older person's brain, Kirk Erickson of the University of Pittsburgh told AFP.

At the conference, the assistant professor of psychology presented new details of a study published in 2011 that involved 120 people aged 65 and older.

- Older brain 'highly modifiable' -

With age, the brain shrinks, he said. Physical activity, however, helps improve its overall functioning and, in particular, increases the volume of the hippocampus by 2 percent, which reverses cerebral aging by one to two years and boosts mental capacities.

"For one, this research has demonstrated the brain remains highly modifiable late in adulthood," Erickson said.

"Even though the brain shrinks and declines tend to happen it does not seem to be as inevitable ... and exercise seems to be a great way to take advantage of this natural capacity for brain plasticity."

What's more, it's apparently not necessary to do a lot of exercise to get that result -- a "modest amount" is all it takes, he said.

However, he acknowledged, "there is still a lot to learn. We don't really know very much about how much is exactly needed."

"Even though we have learned a lot I have to say we still have a long way to go," he added.

"But that being said, physical activity seems to be one of the most promising approaches for positively influencing brain health in late adulthood."

According to the Pew Research Center, the baby boomer generation began to turn 65 on January 1, 2011, with 10,000 doing so each day until 2030, said Cacioppo.

"This has been called the silver tsunami," he said.

Some see an aging population as inevitably one with greater dementia and poor health, as predicted 15 to 20 years ago, he added.

"But in fact we see a decline in disability rather than an increase in part because" of medical advances and people "starting to take better cares of themselves."

Still, a sedentary lifestyle rather than one filled with physical activity is the norm in old age, he said.

"But we have new information about how to better age."