Turns out…the nose may know before the mind does. 

By Mark J Kaylor

Researchers tracking older adults found that a decline in the sense of smell often shows up years before any measurable dip in memory or thinking, and it’s tied to faster buildup of proteins linked to Alzheimer’s. People who could detect fewer odors went on to lose brain volume faster in the regions cognition depends on. The effect was strongest in those carrying a known genetic risk factor, where smell faltered nearly a decade before cognition did.

Walking tells a similar story. Scientists studying gait under “dual task” conditions, like walking while subtracting numbers, found subtle changes in stride and brain white matter long before any obvious cognitive symptoms appeared. The body, it seems, often registers the shift before the conscious mind catches up.

None of this means a forgotten word or a fading scent is a diagnosis. But it does suggest the earliest signals of brain aging may show up in the senses and the stride, not the sentence.

Turns out your nose might be the first to know your mind is changing, long before your mind agrees.

National Institute on Aging. “Loss of Smell Linked to Alzheimer’s Cognitive Impairment and Biomarkers.” Journal of Alzheimer’s Disease, 2022.