Aging is still one of the greatest mysteries in biology
My mother lived beyond the mark of the century. In fact, she died a week after her 101st birthday. But she didn’t become one of those mentally and physically robust centenarians that researchers love to study. At the time of her death, my mother was frail and almost bedridden. Dementia twisted his mind, osteoarthritis crushed his right knee, then his heart gave out.
Even with health issues, her attitude remained strong. She loved to dance and she was a badass in the gym until she was in her nineties. No matter what happened to her body – she also survived two bouts of breast cancer – her youthful appearance made my mother smile, even when she was weak and in hospice.
Every organism ages, even bacteria. Why aging occurs, however, is still one of biology‘s greatest mysteries. Researchers have offered many theories for why we age, but here’s the most common explanation: Damage begins in our cells from early exposure to everything from environmental toxins to pathogens to bad weather. diet and even lifestyle choices like smoking. Over decades, the altered cells weaken tissues and organs, leading to a decline in sparks throughout the body.
Biologically, we age at different rates; some of us age faster or slower than others, and our chronological age (how long we’ve actually been there) can be out of step with our biological age. To measure these differences, the researchers developed molecular clocks, blood tests that track markers on our DNA. These estimates can tell us how much aging has occurred up to a given time, predict lifespan, and whether those years will be healthy. Another blood test measure tells us how fast or fast we age. This knowledge can anticipate who is most at risk for age-related diseases, such as heart disease, and tell researchers whether or not interventions are working.
Some people at 75 are athletic and independent, while others may need help with daily living. But aging is more than the changes our cells accumulate over time, or the gradual accumulation of molecular damage. We also age mentally and our attitudes matter. How we view aging can help or hurt our own health and impact how we as a society view aging, and these views affect us all. “Aging is not just about living longer; we want healthier aging,” says Allaattin Kaya, a researcher specializing in cellular aging and longevity at Virginia Commonwealth University in Richmond.
“The more we understand about aging, the more the public will understand and the more we will see support for aging,” said Patricia M. D’Antonio, vice president of policy and professional affairs at The Gerontological Society of America in Washington, DC. “We are not falling off a cliff because our society is aging.”
The Why and How of Aging
Our risks of heart disease, cancer and diabetes increase over time. The new field of geroscience aims to understand why by focusing on the basic mechanisms of aging: how aging affects disease and how disease affects aging at the molecular and genetic level. Studying aging is complicated, says D’Antonio, because most people end up with multiple chronological conditions later in life.
My mother was in pretty good shape until her 100th birthday. Shortly after, she caught pneumonia. Doctors said it was mild, but she was sick enough to spend a few days in the hospital. She never regained her old strength and her life sitting in a chair turned into frailty, one of the physical signs of aging. Experts call it functional aging, which indicates how fast we can walk, how many times we get up and down from a chair. She also lost her resilience, another molecular marker of aging.
In general, biological aging reflects changes that occur in our cells, blood chemistry and organ function also change over time, says Daniel Belsky, a genetic epidemiologist at Columbia University Mailman School of Public Health. Determining our biological age and rate of aging can help predict a person’s life expectancy and whether those years will be healthy.
Belsky and a team of researchers have designed a molecular tool that measures the rate of aging. This tool can tell you if you are aging faster or slower compared to a calculated standard. They based the algorithm on data collected at multiple points over the years, from 1,000 babies born in 1972 in Dunedin, New Zealand. The measurement is more like a speedometer than a clock, Belsky says. This tool has also been tested in a clinical trial that studied calorie restriction. In this study, the algorithm was able to show that the treatment group had a slower rate of aging.
While these tools give researchers a way to measure such interventions, they are still in the early stages. “We are closer to the start than the end of the development of these biomarkers,” says Belsky
Those golden years
Our attitudes can also impact how we age. These biases start when we’re young, says Di’Antonio. Negative attitudes toward aging are everywhere you look, from birthday cards to commercials to sitcoms.
Age biases can turn us against older people, so we blame them for their health issues, such as type 2 diabetes, Di’Antonio says. People will say, “If only you had eaten well, you wouldn’t have all these problems now,” she says. These attitudes ignore the fact that people can live their lives in areas without grocery stores or even sidewalks. Working three jobs just to survive financially may leave no time for exercise.
Di’Antonio leads the Reframe Aging project, an effort to change the public’s understanding of aging, but changing attitudes will take a generation of work, she said.
Beyond that, our own perceptions of aging can affect our behavior and, therefore, our health. If we think of ourselves as too old for a particular activity, for example, it can cause us to become disengaged and sedentary. Or the constant stress of aging can also have physical and mental consequences. “Beliefs play a huge role in what we do and how we feel about what we do,” says Lindsay Ryan, research associate at the University of Michigan, Ann Arbor.
But research also shows health benefits in people with positive self-perceptions about aging. Plus, it’s normal to have both negative and positive self-perceptions about getting older, Ryan says. “Older people may face declining health and social loss, but can still find satisfaction and meaning in their relationships and activities.”
My mother knew both sides of this double-edged sword. She stayed strong until she couldn’t anymore. At 90, she was healthy enough for knee replacement surgery, but chose not to have the operation – and that’s the kind of choice we should all have. Although I may not live to see my 100th birthday, I hope that mental and physical strength will age as my mother did.
This article was written with the support of a Journalism Fellowship from the Gerontological Society of America, the Journalists Network on Generations, and the John A. Hartford Foundation.