A University of Virginia study indicates that a decline in cognitive function may be happening as early as our late 20s into our 30s, with the average age range being late 30s to early 40s. Our natural potential, genetically-speaking, when we look at traditional cultures with more land-based diets and active lifestyles, is to reach old age with very little cognitive decline. We are designed to be healthy, vital, and engaged with life well into our later years.