In Search of Vigor

In April 1513, conquistador Juan Ponce de León landed on the Florida coast during his famous quest for the mythical fountain of youth.

In this century, the quest continues. However, scientists say vigor comes from within.

Gerontology—the study of the biological, psychological and social aspects of aging—will expand exponentially in the next decades, and at the heart of the research is the question of why some people seem to decline faster than others. “Some people over 65 are very robust, while others are very vulnerable,” says epidemiologist Paulo Chaves. “We want to understand why some people roll with the punches, and others don’t. The study of the physiological aspects of aging is key.”

Chaves illustrates frailty—an increased vulnerability to stressors, or a loss of resilience—with an example: During a heat wave, older people who are not frail adapt to and survive the environmental stress, but those of the same age who are frail are taxed more intensely. Another example is older adults with hip fractures; recoveries vary greatly from person to person.

Characterizing and measuring frailty poses a significant challenge. For example, what observable traits—such as muscle strength and walking speed—are associated with frailty? Through longitudinal epidemiological studies at the School such as the Women’s Health and Aging Study I and II, or the Cardiovascular Health Study, researchers are able to characterize frailty status and physiological responses—glucose, inflammation, cardiovascular dynamics and hormones—to stress. “Biostatistics helps to quantitate those responses,” says biostatistician Karen Bandeen-Roche.

Another challenge is understanding the mechanics of what happens when regulatory systems malfunction. The autonomic nervous system responds to stimuli by inducing the flight-or-flight response; if it doesn’t “turn off” properly, this dysregulation may impair the body. And because systems usually work simultaneously with several other systems, epidemiologists and statisticians must try to define and quantify multi-systemic dysregulation, establishing baselines for what is “normal” and what isn’t.

All of this work has the same aim: to better understand the mechanisms of frailty, which may lead to novel ways to predict and prevent it—or at least slow down the process.

“Everybody will hopefully get old,” says Chaves. The goal is to compress the illnesses associated with aging. “We want people to live longer, but spend less time in a frail state.”