Many of us think of health as something binary. You are either healthy or diseased. Either functioning normally or visibly unwell.
But biology rarely works like that.
In reality, the body is constantly adapting, compensating, and trying to maintain stability in the face of stress, ageing, inflammation, poor sleep, dietary changes, and environmental pressures. Remarkably, these adaptive systems can keep us functioning for years, sometimes decades, even while underlying physiology is gradually shifting away from optimal balance.
Dementia provides a striking example. Most people think of dementia as a disease that suddenly appears in old age when memory begins to fail. Yet many of the biological changes associated with neurodegeneration begin much earlier. Subtle alterations in inflammation, metabolism, vascular health, sleep, and brain signalling may quietly accumulate throughout midlife long before noticeable symptoms emerge. In experimental models, some of these changes can be detected even before behaviour itself appears impaired. In a recent study from our laboratory, led by Dr Junior Bowen, we observed changes in inflammation and dopamine-related signalling in ageing animals before measurable cognitive decline became apparent. Outwardly, the animals still appeared functionally normal. Yet biologically, the system had already begun to shift.
This distinction matters. It challenges the idea that health is simply the absence of diagnosable disease. The body can remain remarkably functional while underlying adaptive systems are slowly drifting away from stability. By the time symptoms finally appear, the biological imbalance may have been developing for many years. Understanding these earlier changes may ultimately be one of the keys to healthier ageing — not simply treating disease once it appears, but recognising when physiology first begins to lose resilience.