It’s a seemingly undeniable truth that aging is inevitable. But what if everything we’ve been taught to believe about aging is wrong? What if we could choose our lifespan?
David Sinclair, PhD, AO, is a professor of genetics at Harvard Medical School. One of the leading innovators of his generation, he has been named by Time as “one of the 100 most influential people in the world” and top fifty most influential people in healthcare.
In his groundbreaking book Lifespan – Why We Age—and Why We Don’t Have To, Dr. David Sinclair, leading world authority on genetics and longevity, reveals a bold new theory for why we age. As he writes: “Aging is a disease, and that disease is treatable.”
This eye-opening and provocative work takes us to the frontlines of research that is pushing the boundaries on our perceived scientific limitations, revealing incredible breakthroughs—many from Dr. David Sinclair’s own lab at Harvard—that demonstrate how we can slow down, or even reverse, aging. The key is activating newly discovered vitality genes, the descendants of an ancient genetic survival circuit that is both the cause of aging and the key to reversing it. Recent experiments in genetic reprogramming suggest that soon we may not just be able to feel younger but become younger. Through a page-turning narrative, Dr. Sinclair invites you into the process of scientific discovery and reveals the emerging technologies and simple lifestyle changes—such as intermittent fasting, cold exposure, exercising with the right intensity, and eating less meat—that have been shown to help us live younger and healthier for longer. At once a roadmap for taking charge of our own health destiny and a bold new vision for the future of humankind, Lifespan will forever change the way we think about why we age and what we can do about it.
In this interview, I speak to Dr. David Sinclair, professor of genetics at Harvard Medical School, and author of Lifespan about why we age, why we don’t have to, and what we can all do to extend and enhance our lives.
Q: Why did you focus your career on understanding our lifespan?
[David Sinclair]: When I was a kid, I wanted to do something that would keep my family healthy and around for longer. All kids want their parents and grandparents to live longer and not get sick – I just made it a mission. That evolved into a mission to save humanity from suffering and disease.
We do a good job at dealing with individual diseases, but for some reason, we have this mental block that means we cannot address most of them at the same time, as though we’re supposed to just let ageing occur. We have a lot of science now that says that ageing can slow, or even be reversed. In the not too distant future, we will be treating ageing how we treat cancer and heart disease today.
Q: Is the pace of our ageing inevitable?
[David Sinclair]: I got into a bit of trouble with my colleagues because I called the book Lifespan: Why we age, and why we don’t have to. I wanted to make sure that readers understood that in the future, we are going to have a choice about how fast we age. Already there are ways to live your life and even drugs on the market that have a very high likelihood of slowing down the ageing process. We’re on the cusp of having technologies that can literally reverse your age. The idea that we have to be sick in our 80s and 90s is going to go away pretty quickly within our lifetimes.
Ageing is malleable, we can control it. 20% of our health in old-age is due to genetic factors, and the rest is due to our lifestyle. We can measure this clock. It’s literally measuring chemicals in our own DNA. My lab has just brought the cost of this test down 100x and we’re going to be offering it to people at doctorsinclair.com – we already have 80,000 people signed up. The test tells you how old you are biologically, not chronologically. It’s somewhat like a credit score! One number to rule your health in the future.
Here’s the good news…. That number can be changed. If you smoke, if you don’t exercise, if you eat lots of fatty foods, that number will accelerate and if you do the right things, perhaps even take some medicines, you can slow that number down – even reverse it. It all comes down to what I call the information theory of aging, that is that clock that we measure.
We’re discovering how it is that some animals can live for 300 years, like the Bowhead whale. If they can do it, we can do it. We can engineer our bodies, we can make medicines.
In December 2020, we published in the journal nature that we could turn on 3 genes in mice, that are normally only switched on in embryos. By doing this, we could reverse the age of complex tissues in adult mice. We used this system to restore eyesight to blind, old, mice!
Certainly, within our lifetimes, perhaps only 5 years from now, we will be reversing the age of the body.
Q: What will it mean for our sense of purpose if we extend our lives?
[David Sinclair]: We have no problem living twice as long as people in the middle-ages on average. Living longer gives more purpose, it means you can achieve more, you can help your kids more, you can leave a legacy, you can change careers. It’s going to be a very different world. There are people who are now able to reverse the age of their body – at least anecdotally – by a decade.
We will be in a world where people can turn back the clock by decades. When that happens, we’re going to have a lot more options in life. We won’t get sick, we won’t be worried about getting cancer when we’re 60 or 80. We will have a planet where we need to change the way we view old age. 80 is not going to be old anymore, nor is 90.
Even if we could live to 1000 years, life would still be too short for many of us. I’m 51, that went in a blink of an eye. I don’t think finding purpose in our lives will be an issue….
I do think we will need to be more careful with our bodies. We’re not going to cross the road so easily; we have to look left and right a little more. As we live longer, we value life more, and so we need to make sure we don’t die from accidents, or preventable disease.
Longer life gives us a more purposeful life.
Q: How will longer life impact our economies and productivity?
[David Sinclair]: Economically, the world is going to be much richer if people live longer. That means more money to spend on urgent challenges such as climate change. Advanced countries spend more than 15% of their GDP on healthcare, which should really be called sick care.
What we’re talking about here is the ultimate disease prevention. By reducing the burden of disease by 5%, you would save trillions of dollars. We are literally right now living through one of the biggest revolutions in human history, certainly in medicine, and most people aren’t even aware that it’s about to happen.
Q: How well can we control ageing?
[David Sinclair]: In my lab, we can control ageing easily. We have mice where we can dial up the ageing process or reverse it. It’s not that hard when you know how. One of the main contributors to ageing is DNA damage. Primarily and specifically, broken chromosomes. Each of our cells experiences broken chromosomes at least a couple of times a day and fixes them – but that means that a trillion times a day this is happening. It’s a lot. It unwraps our DNA and causes disruption to how our DNA is folder into cells. Eventually cells then turn the wrong genes on, and they lose their ability to function. That, I believe, is the switch that controls ageing.
Until recently, we didn’t know there was a backup copy of the information which has been corrupted, and now we can reset it using an embryonic gene trick. Ultimately, I think we’ll be able to pop a pill and reset our body’s age. It takes us about 4-8 weeks currently to reset the age of a mouse, it shouldn’t be any different for humans.
Q: Will reversing age impact how we handle other chronic disease?
[David Sinclair]: Ageing is not separate from Alzheimer’s or heart disease. The leading causes of those diseases is the ageing process, which we can now control. Based on what we’re doing in the lab, we know that if you turn the clock back, those diseases go away- that’s a revolution. We’ve been working on a band aid system trying to fix the diseases that are already there, while ignoring the main cause of those diseases which is the ticking of that clock.
Q: How can we improve our lifestyles to prevent gene damage and ageing?
[David Sinclair]: I avoid radiation as much as I can, particularly X-Rays which damage chromosomes. There are chemicals all around us which also damage our chromosomes and accelerate ageing. Plastics, food dyes, and even the yellow found in inkjet printers…
Flying is bad… poor sleep is bad… high amounts of stress… a lack of exercise…. The wrong diet… obesity… smoking… these are all things that accelerate ageing. We know that if you get sunburnt too much, you’ll age faster too!
All of these things are accelerating the clock in our body, breaking our chromosomes.
Q: What do you do to slow down your own ageing?
[David Sinclair]: I don’t smoke, and I exercise regularly – aerobically a few times a week and also weightlifting. I maintain a lean body mass. Today, aged 51 I have the same body weight I had when I was 20.
I also get enough sleep and eat the right foods – which tends to be more plant based, and less read meat. I also try supplements that we’ve discovered in our lab. Resveratrol (which is derived from red wine) is part of my regimen, as is NMN which is a NAD boosting molecule that turns on the body’s defenses. I also take a drug called metformin, which was designed to treat Type 2 diabetes, but is associated with a lower risk of heart disease, cancer, frailty and Alzheimer’s.
What’s coming down the line is even more exciting – the ability to reverse your age, multiple times, by decades. The ability to rejuvenate tissues that you thought were untreatable or irreversibly damaged.
Q: How is technology enabling longer lifespan?
[David Sinclair]: Technology enables us to monitor the body constantly rather than going for an annual checkup. Today, I’m wearing a device on my chest that can tell me if I’m going to have a heart attack next week or if I have pneumonia versus a cold.
I used to be skeptical about whether I could live an additional 5 years. Now, I’m convinced that I could live 20 years beyond what I would have done. If you do the right things (eat well, sleep well, restrict feeding, don’t smoke) those things will give you at least an extra 14 years on average, for the average person. That’s the easy stuff.
Drugs on our near horizon will give us easily another 20 years, and the drugs not far behind that, another 100. I’ve never been more excited about the prospect of human health than I am right now.
Q: What do you hope your legacy will be?
[David Sinclair]: I don’t worry about dying. I’m not doing this work to live longer. Anyone who’s seen me drive my Tesla Model S knows that I’m not worried about dying! <laughs> I would like to see the future. I want to stick around as long as I can to have the greatest impact possible.
I started on this quest to make a difference and to make the world a better place. I want to show future historians that humanity can do much better than we did in the 20th century.