There is no single ingredient
The consistent factors in healthy-aging research, and in Estonian public health guidance, are mundane: enough sleep, regular movement, a mostly plant-based diet, moderate alcohol, and stress management. None of these is dramatic. Together they shape function in your sixties, seventies, and beyond. What makes them work is not intensity but the fact that they survive a normal week — a commute, dark December mornings, a busy Thursday.
Where guidance tends to agree: these habits overlap with each other. Better sleep makes movement easier; regular movement deepens sleep; a steadier blood-sugar curve after meals makes the afternoon less of a fight. That is why single-habit fixes rarely hold, and why a small connected routine does.