Peakspan and Healthy Life Extension: Two New Framings for Longevity Science

The responses to my last newsletter — on whether we should prioritise lifespan or healthspan — were evenly divided. Interestingly, while that debate was unfolding, two well-respected longevity scientists independently proposed new ways of framing what we are actually trying to achieve. Both deserve attention.

David Barzilai’s concept is quite self-explanatory: he advocates for “healthy life extension”. It neatly, to my mind, squares the circle between healthspan and lifespan, offering the goal of both improving the quality of life and extending that healthy life into the future. Both adding life to years and years to life, if you will. Not everything that does the one also does the other, but obviously the combination is attractive to most people. I like it, and will try to use “healthy life extension” in my own speeches and writings wherever it fits.

Alex Zhavoronkov recently published a blog introducing a different concept: “peakspan” — a term also worth adding to our vocabulary. The chart below, from his post on forever.ai, captures the idea:

Chart: Alex Zhavoronkov / forever.ai

While this is a complicated chart, the essence of the idea is simple – we should aim to extend the period of life when our performance remains above the 90% of maximum that we typically enjoy in our early twenties. But, of course, we need to break performance down to the dimensions you see on the right of the chart – cognitive, cardiovascular, etc etc.

It also contains the concept of the “biological retirement age”, as the chronological age when functional decline has made adequately useful work no longer possible. As the chart implies, can we move that from the typical retirement age of the mid-60s to the mid-70s, or beyond?

Two comments from me. First, the human body is a system, and the dimensions that Alex calls out are intimately interconnected. Chronic inflammation, for example, can affect all dimensions of performance. Indeed, that is why I argue that we must persuade regulators and payers to approve treatments for chronic inflammation, confident that this will delay or avoid a host of potential diseases in later life.

Second, “adequately useful work” is very professionally determined. I know I could not perform well as a bricklayer, lifting hods full of bricks up steep ladders, but I do hope my speaking and writing - on the intersection of AI, longevity science and precision medicine - remains useful work, at least for some people.

But at its essence Alex’s focus on performance has to be right. What makes life fulfilling is the ability to add value to the world (and enjoy life itself) unhindered by physical or mental constraints - although we can all think of people who have overcome severe handicaps to achieve great things. And, economically, as the blog points out, keeping more of the population at or close to peak performance not only add to society’s economic output but also reduces the call on resources that retirement or frailty bring. 

Of course, developing and approving ‘therapies’ based on improving or maintaining human performance adds another layer of regulatory challenge to that already faced by the geroscience field. We still do not have healthspan reduction as a recognised marker of therapeutic efficacy, although we do have a growing realisation that some treatments, for example GLP-1 receptor agonists, can delay disease across a number of body systems. In future, can we persuade regulators and payers to approve agents that maximise or peakspan? I hope so, but it won’t be easy.

The language we use to describe our goals shapes the research we fund, the trials we design, and the policies we advocate for. Whether you find yourself drawn to “healthy life extension” or “peakspan”, I’d be curious to know which framing resonates most with you — and why. Does one feel more scientifically rigorous? More politically defensible? More personally motivating? Let me know your thoughts.