Our chronological age is not exactly the same as our biologic age. Just like we can 'look young' or 'have the muscles of a young body,' we can have the biological age of a young body on a cellular level.
This is linked to the age of our chromosomes, and known as the epigenetic age. The chromosomes undergo aging called DNA methylation. DNA methylation-based 'epigenetic clock' correlates strongly with chronological age, but it is currently unclear what drives individual differences, but here is one possible way.
Menopausal hormone therapy begun as menopause was starting was associated with lower mortality in countless studies in the late 20th century. Mostly it thought that hormone therapy prolonged life to be due to less cardiovascular disease. It was only the studies done on women who began hormone therapy many years after menopause that did not have this effect.
Now we have evidence that fundamentally, on a microscopic level, hormone therapy may truly have anti-aging effects.
We age one cell at at time. Cells can age through actual physical trauma, but they generally age through three main pathways: a)a breakdown in the reproducing stage, b)cancer gene inducing mistakes, or c)damage to the DNA of the cell.
The control of this cell by cell aging determines our biologic age, and the pace that this occurs is collectively known as our epigenetic clock. If the clock speeds, as it will through menopause, we age more. If the epigenetic clock slows as we age, youth is restored, and metaphorically speaking time is added to our clock.
Menopausal hormone therapy has been shown to have some direct cellular effects that can reverse epigenetic clock changes! What role toxins, nutrition, exercise, circulation, and a host of other factors have in this process is still working out.