In 2020, scientists drilling about 230 feet beneath the seabed of the South Pacific gyre found microbes in sediment up to 101.5 million years old, and with a few nutrients they started growing again. This episode uses that discovery to explore suspended animation, a profound slowing of metabolism in which heartbeat and breathing become nearly undetectable. It explains why humans seem shut out: the brain uses about 20 percent of the body’s oxygen, stores none, and begins irreversible damage after about five minutes without it as calcium floods cells and enzymes digest them from within.

Cold changes the math. Swedish radiologist Anna Bågenholm spent 80 minutes under the ice of a frozen stream in 1999 with no heartbeat and recovered, and toddlers Erika Nordby and Paulie Hynek were revived after hours of hypothermic cardiac arrest. The episode explains the Arrhenius equation, bone lesions at Spain’s Atapuerca site that may point to hominin hibernation, and Emergency Preservation and Resuscitation, which replaces blood with chilled solution. Researchers are also testing hydrogen sulfide to put cells into a chemical safe mode.

• Mitsutaka Uchikoshi’s claimed 24 days on a Japanese mountain and the skepticism around it
• Lorises and bush babies entering torpor to survive scarcity
• Induced hypothermia in open heart surgery since the 1970s
• University of Pittsburgh dogs revived after three hours of deep stasis
• Massachusetts General Hospital pig trials with a 90 percent success rate