How Did Low Cardio Fitness Raise Death Risk Fivefold?

On Huberman Lab, cardiorespiratory fitness shows a profound link to all-cause mortality. People in the bottom 25 percent of maximal oxygen uptake for age and sex have roughly a 2x difference in risk versus people at the 50th to 75th percentile, and a 5x, 400 percent, difference versus the top 2.5 percent.

The comparison stays inside age and sex. Against the 50th to 75th percentile, the bottom 25 percent lines up with about a 2x difference in risk. Against the top 2.5 percent, called the elite level for a given age, the bottom quarter lines up with a 5x difference, a 400 percent difference in all-cause mortality. Dr. Peter Attia says that is probably the single strongest association seen for any modifiable behavior. Elite means the maximal oxygen uptake number for the age group, and a person does not have to be a world-class athlete to reach it.