My cortisol was dangerously high while I was pregnant. In a body of its own, that cascade ages you. Cortisol, then inflammation, then oxidative stress, then telomere attrition. For a body attached to mine, it was lethal. I gave birth to a son I never got to bring home.

I had spent my life studying every sound human beings have made to steady one another. Prayer, chant, scripture, silence. I used all of it, and my cortisol rose anyway, and I lost him. Afterward I stopped asking what I felt and started asking what could be measured.

In a room built to remove all sound, I heard my own. Blood in its channels. Cells dividing. Hair growing. A frequency as unique as my fingerprint, and it cannot be altered, no matter what you have been told. Your DNA recognizes it as your home frequency. That sound is the most aging thing your body absorbs, or it is the key to your longevity. Both are available.