To be clear, this wasn't Sapolsky's research. In one of his books he referenced the findings of another researcher (physicist, chess GM, and textbook author Ler

To be clear, this wasn't Sapolsky's research. In one of his books he referenced the findings of another researcher (physicist, chess GM, and textbook author Leroy DuBeck), with caveats about that figure being extrapolated and thus not a direct measurement at all. As per usual, this claim has been repeated all over sports/medicine journalism with improper attribution and no mention of the caveats.