Running Out of Air: Low Oxygen Fast-Forwards the Aging Clock — But Only in the Old, and the Damage Largely Rewinds (opens in new tab)

One month of severe intermittent low-oxygen exposure pushed the epigenetic clocks of old mice forward by several “months” of aging across lung, spleen, and heart, while leaving young-adult mice untouched — and most of that acceleration reversed once normal oxygen returned. A parallel human dataset of young trekkers at 5,260 m showed the same clocks ticking faster within days. The aging clock may not run at a fixed speed. A team led by the National Institute on Aging and Steve Horvath’s Epigen...