27. Human Lifespan Has a Soft Limit

Is there a maximal human lifespan? There is no hard biological limit (like a wall), but there is a soft limit imposed by species biology and manifested as the pattern of functional decline (54, 55). As we eliminate early causes of death (childhood mortality, infection, heart disease, etc.), we reveal deeper, more complex failures (neurodegeneration, loss of matrix integrity, etc.) that are harder to fix, and even when they are eliminated, there is still a limit. Dietary, lifestyle, and most pharmacological interventions are unlikely to break the species maximum lifespan limit, as such interventions primarily modulate a limited number of pathways rather than altering the multidimensional structure of the deleteriome. In humans, the maximal observed lifespan is 122 y and 164 d in women, and 116 y and 54 d in men, whereas the species maximal lifespan may be around 120 to 150 y (56). This limit may be broken in the future with more radical approaches, such as multiple combined interventions, replacement, age resetting (rejuvenation), hybrid technologies, and the adoption of strategies from long-lived species.