Researchers are exploring a comprehensive measure known as intrinsic capacity to assess overall health and functional ability throughout the aging process. The concept aims to provide a single metric that captures various aspects of an individual's physical and cognitive capabilities, potentially enabling earlier detection of decline and more effective interventions.
Intrinsic capacity was established by the World Health Organization (WHO) in 2015 as part of its healthy aging initiative. The measure is designed to shift focus away from individual diseases toward maintaining and maximizing older adults’ functional capacities. It encompasses five key domains: cognition, locomotion (including strength and mobility), sensory abilities (vision and hearing), psychological wellbeing, and vitality, which reflects energy levels and resilience to physical stress.
Performance in these subdomains is evaluated through tests already commonly used in geriatric assessments. These measurements are combined to generate an intrinsic capacity score, which has been shown to correlate with risks of disability and mortality in older adults. Experts emphasize that the value of intrinsic capacity lies less in a one-time measurement and more in ongoing monitoring, which could reveal early signs of functional decline even in individuals who appear healthy.
“This allows you to start thinking about what is affecting someone’s capacity and how to intervene earlier to prevent later decline,” said Dr. John Beard, a professor of productive aging at Columbia University’s Mailman School of Public Health and a contributor to the concept’s development. While cognitive and physical tests tend to yield near-perfect scores in younger, healthier populations, researchers are investigating additional measures that could enable intrinsic capacity to be assessed across a broader age range.
Intrinsic capacity is currently being tested in clinical settings, including a trial in France where older adults complete regular questionnaires assessing their intrinsic capacity. Participants receive tailored health recommendations, and those experiencing declines are referred promptly for medical or geriatric nurse follow-up. Similar studies, such as one recently launched in New Mexico, aim to determine whether this early intervention approach can extend longevity, though conclusive data remain forthcoming.
The metric is also at the center of a research initiative funded by the Advanced Research Projects Agency for Health (ARPA-H), part of the U.S. Department of Health and Human Services. This program seeks to develop reliable endpoints for clinical trials testing drugs intended to delay aging and extend health span. Because aging is not classified as a disease by the U.S. Food and Drug Administration (FDA), regulatory approval for therapies targeting aging itself has been challenging. Intrinsic capacity may offer a way to demonstrate treatment benefits relevant to aging.
Andrew Brack, leading the ARPA-H project, noted that intrinsic capacity could help bridge this gap by linking the metric to individuals’ functional status and lifespan, and by showing that lifestyle or pharmacological interventions can improve it. In 2022, the WHO included “aging associated decline in intrinsic capacity” in the International Classification of Diseases, signaling growing recognition of the concept.
“We have to be clear we don’t know if this will work,” Brack said. “But we’re scientists; we have to do the experiment.”
If successful, intrinsic capacity could become a foundational tool in managing aging, guiding both clinical care and the development of treatments aimed at enhancing health and function in later life.