As clinicians, we are trained to look for disease.

We measure blood pressure, blood sugar, lung function, and imaging results, often waiting for pathology to declare itself before we intervene. During the COVID-19 pandemic, however, many of us noticed something unsettling: patients were not only arriving later, they were arriving weaker.

Recent evidence confirms this clinical intuition. An analysis published in The BMJ, examining health records from more than 30 million people, showed substantial and persistent reductions in disease detection after the pandemic. Diagnoses of depression fell by nearly 28 percent, asthma and chronic obstructive pulmonary disease by more than 15 percent, and osteoporosis by over 11 percent. These declines did not reflect improved population health. They revealed diagnostic blind spots created by system disruption.

The hidden danger of functional decline

The danger is not simply missed diagnoses. The deeper problem lies in how modern health systems rely almost exclusively on diagnosis as the trigger for care. When access is disrupted by pandemics, disasters, or social instability, the system loses visibility over those who are quietly becoming most vulnerable.

In aging populations, adverse outcomes rarely begin with sudden illness. They usually follow gradual erosion of functional capacity: muscle strength, gait stability, cardiopulmonary reserve, and the ability to regulate body temperature. When these capacities decline, even modest stressors can become life-threatening.

I saw this reality starkly illustrated in my own country, Taiwan. During a recent cold spell, media reports tracked 181 out-of-hospital cardiac arrests in less than a week, most involving older adults. Many had no acute medical diagnosis. What they lacked was physiological reserve.

Frailty as a clinical lens

Frailty provides a crucial clinical lens. Research published in The BMJ has identified frailty as a breakthrough point for managing multimorbidity, precisely because it captures cumulative functional decline rather than isolated disease. By the time frailty becomes clinically obvious, patients face sharply increased risks of falls, hospitalisation, institutionalisation, and death.

Social context further amplifies these risks. A population-based cohort study from Wales, published in BMJ Medicine, found that older adults living alone had significantly higher risks of unplanned hospital admission and transition to long-term care, even when they had fewer diagnosed chronic conditions than peers living with others. Social support, it turns out, can be as protective as medical treatment.

Reframing exercise as therapy

Yet many health systems still equate safety with immobility. Wheelchairs are prescribed, rest is encouraged, and fall prevention is framed as movement reduction, often accelerating the very decline we hope to prevent. Functional loss is treated as inevitable, rather than as a modifiable risk factor.

Some countries are moving in a different direction. Community-based exercise programmes in Japan and first-line exercise prescriptions in parts of northern Europe treat mobility and strength as clinical priorities, not lifestyle extras. These models recognise that exercise is not advice; it is therapy.

Taiwan’s public discourse has begun to reflect this shift. A recent commentary in the Taipei Times argued that “exercise as medicine” should be embedded into long-term care policy rather than left to individual motivation. The emphasis was not athletic performance, but dignity, the ability to stand, walk, and participate in daily life.

A call to action for clinicians

For clinicians, the message is clear. Improving disease detection is necessary, but insufficient. We must also defend functional capacity, especially when traditional diagnostic pathways fail. Functional measures offer near-real-time insight into vulnerability, even when clinics are closed and appointments delayed.

Health care should not begin only at hospital admission, and compassion should not be confined to the bedside. If medicine is serious about resilience in an aging world, preserving mobility and independence must become as urgent as diagnosing disease. It is time to treat function not as a vital sign we merely monitor, but as a reserve we actively build.

Gerald Kuo, a doctoral student in the Graduate Institute of Business Administration at Fu Jen Catholic University in Taiwan, specializes in health care management, long-term care systems, AI governance in clinical and social care settings, and elder care policy. He is affiliated with the Home Health Care Charity Association and maintains a professional presence on Facebook, where he shares updates on research and community work. Kuo helps operate a day-care center for older adults, working closely with families, nurses, and community physicians. His research and practical efforts focus on reducing administrative strain on clinicians, strengthening continuity and quality of elder care, and developing sustainable service models through data, technology, and cross-disciplinary collaboration. He is particularly interested in how emerging AI tools can support aging clinical workforces, enhance care delivery, and build greater trust between health systems and the public.