Longevity should be measured by how well people live, not simply how long they survive, Silicon Valley biohacker Bryan Johnson and physician Carl Seger said, arguing that extending life without preserving physical and cognitive function misses the true purpose of health innovation.
They shared their insights in a conversation with Jany Hejuan Zhao, the founder and CEO of NextFin.AI and the publisher of Barron's China, during the 2025 T-EDGE conference, which kicked off on Monday, December 8, and runs through December 21. The annual event brings togehter top scientists, entrepreneurs and investors to discuss pressing issues of the AI era.
Johnson, founder and CEO of Blueprint, said the prevailing focus on optimising biological indicators such as blood pressure or cholesterol offers only a narrow definition of health.
“We have certain critical periods in our learning process where, when we're very young, where we can learn languages very quickly. There are times in our life where we have our peak physical capacity, our peak learning capacity, where we experience novelty. And then as we age, we learn, our learning becomes more challenging. We get more fixed in our ways, our body starts breaking down, our brains are breaking down,” Johnson said. “The bigger goal is to take us back to those most beautiful times of our biological existence. And that's what I believe is going to be possible, that we will be able to take ourselves all the way back to critical periods of learning and experience and novelty and physical ability that most of us adults haven't felt for decades.”
Seger, MD, CEO of Wild Health and Johnson’s chief physician, echoed that view, stressing that longevity without independence and functionality holds little appeal. “You can live a long time in a nursing home, but nobody really wants to do that. People want to be doing the things that they want to do,” Seger said. “And that when people get to their why, whether it's usually ends up being out of some driven from love of they want to see their, they love their kids, they want to see their grandkids, they want to be, not just see them, they want to do things with them. They want to experience life.”
Seger outlined the core pillars needed to preserve quality of life, including reducing the risks of cardiovascular disease, cancer and neurodegenerative conditions, maintaining metabolic health, limiting chronic inflammation and muscle loss, and supporting mental well-being.
When asked whether people should prioritise perfect biological metrics or meaningful life experiences, both men said the two should ideally work together. However, if forced to choose, quality of life would come first.
Metrics are tools, not the destination, Johnson said. A life defined by purpose, connection and growth matters more than a long life reduced to numbers. That said, biological optimisation makes those experiences possible, it’s hard to fully engage with life when the body and mind are in decline, he added.
