Still climbing: These days, getting over the hill means a much longer trip

lifespan

If she were living 100 years ago, Alice O'Dea would probably be feeling pretty nervous right about now.

At 52, the Highland Park-based writer and community activist is just a year shy of the 53.2 years the average American woman was expected to live in 1910, according to U.S. Census data.

O'Dea isn't sure about claims that "50 is the new 30," but nor does consider herself remotely elderly. Even if she does qualify for AARP membership, she says she's still a long way from the nursing home.

"I'm still pushing back," she says. "I imagine I'll qualify as 'old' at some point, but it's hard to imagine what will slow me down."

Thanks to medical advancements in the last century, O'Dea is right to feel less burdened by a half century of life.

According to the National Institute on Aging, there was a "dramatic increase" in average life expectancy in the last century. Most babies born in the year 1900 would be considered middle-aged by 25. Babies born in 2010, however, can expect to live to be 78, according to the Centers for Disease Control and Prevention.

In fact, O'Dea is actually at the most desirable time of life, according to a Harris Interactive online poll conducted in 2013. When asked how old they would choose to be if they could stop time at any point and remain in good health, the majority of the 2,200 respondents settled on 50 years old. The pollster asked the same question in 2003 and the most popular response was 41.

Apparently, getting over the hill means a much longer climb than it used to. So what does it mean to be "old" in 2014?

HEALTHSPAN, NOT LIFESPAN

Anecdotally, many people echo O'Dea's sentiment, saying they think of becoming old not in terms of passing a specific age but reaching the point at which they lose the ability to do the things they love.

"I am going to be 53 and by no means feel that," writes Karen Doerr Rogers of Chattanooga in a post on the Times Free Press Facebook page. "I mountain bike ... live a young life [and] have very few health issues. Each decade is better. The next one means I get to retire and play."

Some people may think of aging in terms of life expectancy alone, but scientists say the greatest recent gains in aging research haven't been toward prolonging life but rather in improving "healthspan," or quality of life.

Although it marks a stark improvement over health prospects at the dawn of the 20th century, the current American lifespan has not dramatically increased in the last 50 years. By 1950, Americans were living 21.2 years longer - about a 45 percent improvement - than in 1900. Between 1960 and 2010, however, lifespan increased by just nine years, a gain of about 13 percent.

Those leaps in the first half of the century were driven largely by advances in disease prevention and sanitation following the establishment of the nation's first health departments in 1908, according to the CDC. By 1950, vaccines had been developed for several illnesses, including tuberculosis (1927) and influenza (1945), which were the leading causes of death at the turn of the 20th century, according to statistics released in 2012 by the New England Journal of Medicine.

According to the Journal of Medicine's findings, the greatest health risks in America since the 1950s have been cancer and cardiovascular disease, which are classified as age-related conditions by many in the medical community.

But a longer life doesn't tell the whole aging tale, experts say.

In the last two decades, simply prolonging life hasn't been the primary goal of research into the biology of aging, says Judith Campisi, a professor at the Buck Institute for Research on Aging and a senior scientist at Lawrence-Berkeley National Laboratory in Berkeley, Calif.

"Nobody wants to live longer if you're going to fall apart, right?" Campisi asks, laughing. "The Holy Grail of age research is to find things that will extend healthspan rather than lifespan."

Campisi's primary research is into how the body's cellular response to stress drives the aging process, especially the dramatic increase in susceptibility after age 60 to a host of age-related conditions such as loss of vision, Type II diabetes and osteoporosis.

Campisi says extending lifespan beyond the presumed biological maximum of about 120 years is "a big black box" for many researchers. However, she adds, ensuring that people can maintain the same level of health and physical ability into their former twilight years has been the primary focus of many researchers for the last 20 years.

"I'm very optimistic about that," Campisi says. "It's really the most intensive area of research, to find ways and means to extend the healthspan of people, so the last 10 years of your life aren't spent mentally incompetent, sitting in a wheelchair and dribbling. That is how a lot of us will end our life, unfortunately. It's a huge problem."

THE WAITING GAME

If younger Americans feel like old age is further away than ever, it may be because they're waiting to make many of the life's traditional milestone decisions.

According to U.S. Census statistics, women are waiting an average of 4.4 years longer to have their first child, from an average age of 21.4 in 1970 to 25.8 in 2012.

Matrimony is being put on the back burner as well. The median ages for men and women getting married in 2012 were about 28 for men and 26 for women, respectively, higher than they were in 1960.

Although she's closing in on her third decade - a common freak-out point for millennials - 29-year-old Chattanooga State Community College nursing student Asley Bishop Magouirk says she feels like her life hasn't even started yet. As a consequence, she says, she sees 40 as a milestone to look forward to, not to dread.

"My husband and I have not started a family and don't plan on it until I am set in my career - so mid-30s," she says. "I think 40 will be an exciting time for us, having kids and the dream house we want."

THE WEALTH GAP

When it comes to aging, the playing field is far from level. Experts say the debilitating health conditions that largely mark the onset of old age are much more prevalent in developing than income-rich nations.

"Life expectancy is only increasing in places with good access to health care," says Dr. Gordon Lithgow, another professor at the Buck Institute. "If 40 really is the new 30, it's only happening in affluent places."

In the 2014 edition of its World Health Statistics report, the World Health Organization reported that life expectancy remains lower than 55 in nine sub-Saharan African nations. In the United States, Americans have been able to expect longer lifespans than that since the 1930s.

Even among other low-income nations, life expectancy lags far behind wealthier countries. Males in low-income nations can expect to live 60.2 years, about 26 percent less than in developed nations. Women in low-income nations live slightly longer, 63.1 years, but fall even further short - 30 percent - of their high-income peers.

By comparison, life expectancy in the United States might seem remarkable, but it's not even in the top 10 of the CIA World Factbook's list of the longest-lived nations. According to 2014 estimates, the U.S. is the 42nd longest-lived country, well behind lifespans in Japan (84.46 years), Switzerland (82.39 years), Canada (81.67 years) and the U.K. (80.42 years).

QUALITY ASSURANCE

To some, staving off mental and physical infirmity is far more important than living longer, and experts say the best way to ensure that turning 60 feels more like turning 40 isn't the result of swallowing a magic pill but adopting better habits as early as possible.

Dr. Walter Bortz is a clinical associate professor of medicine at Sanford University and the author of many books about longevity and aging. In a post on his website about the health expectations of the baby boomer generation, the oldest of whom began turning 65 in 2010, he explains that, unlike earlier generations, boomers have exhibited much higher expectations for their twilight years' quality of life than past generations.

"They will be more activist, more informed and less tolerant of inefficiency and incompetence, but very concerned about their own personal well-being," Bortz writes. "There will be less interest in how old you are or what disease you have, than in what you can do.

"This emphasis on function is fundamentally what life is all about in the first place. ... Their focus will be more on what you can do - what is right about you - rather than what is wrong about you. Health, not disease, should be celebrated."

Some say accepting diminished capability could be the first step down a slippery slope into old age.

O'Dea says she didn't think of her mother-in-law as elderly until she began complaining that she was unable to touch her feet to give herself a pedicure. Instead of working with a physical therapist to retain or restore her strength, balance and flexibility, however, she chose to get pedicures and allow someone else to take over her foot care. She died just two years later at age 77.

"That's about when she started to seem 'old,'" O'Dea says. "She'd let go of being able to do pretty basic things."

Dr. David Bass, vice president for the Benjamin Rose Institute on Aging in Cleveland, Ohio, says lifestyle choices and healthy behaviors such as physical and mental exercise, good nutrition and social interaction are crucial to maintaining quality of life and prolonging healthspan.

"More older adults are doing things that result in better health and high quality of life into older ages than ever before," Bass writes in an email. "While health is a key factor, it is not the only factor, as there are many young and old people who maintain high quality of life and high levels of happiness despite their health problems."

Steve Witt, director of the Southeast Tennessee Area Agency on Aging and Disability, which serves Hamilton and nine other regional counties, says he's recently seen an upswing in the number of participants age 55 and older in the agency's active lifestyle programs, including line dancing, Zumba and computer and social networking classes. The classes are designed to help participants maintain their level of physical ability, retain their independence and stave off the need to rely on assisted living services. That, the 63-year-old Witt says, helps many of them feel younger for longer.

"It seems that those who have taken care of themselves physically and mentally ... have a better quality of life than 60-year-olds of past generations," he says. "Sadly, for many people this is not true because of disease or choice of lifestyle."

Contact Casey Phillips at cphillips@timesfreepress.com or 423-757-6205. Follow him on Twitter at @PhillipsCTFP.