‘Curiosity is Perhaps the Truest Form of Longevity’

Longevity Expert Nils Behrens on sleep, social connection, and our fascination with living longer.

By Naomi Jödicke –
05/31/2026

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Source: Nils Behrens

Longevity Expert Nils Behrens

Longevity has become far more than a trend. Beyond supplements, biohacking, and the pursuit of optimization, a more fundamental question is emerging: Is longevity really about living as long as possible – or about staying healthy for as long as possible? Healthwise podcaster and author Nils Behrens has spent years exploring this very tension. Today, he is one of the leading voices in longevity and holistic health. In this conversation, he speaks about what health really means, why loneliness can be more dangerous than smoking, and why sleep is, in his view, nothing less than “repair.”

Nils, your SPIEGEL bestseller “Spaziergang zur Unsterblichkeit” (“Walking Towards Immortality”) begins with the sentence: “I hate longevity.” That’s rather surprising. Why begin that way?
Nils Behrens: Of course, it’s a small provocation. But only a small one (laughs). I think the term “longevity” is often misleading, because most people don’t just want to live longer. No one wants to spend as many years as possible living with illness or limitations. What people really want is to remain healthy for longer. Today, we distinguish between lifespan and healthspan. Lifespan merely describes the length of a life – in other words, what appears on a gravestone: date of birth and date of death. Healthspan, on the other hand, refers to the years we live in good health and free from age-related illness. That’s why I always say that simply living longer is not enough. The real question is how we live.

What does that mean in practical terms?
The idea of longevity can sound like planting an apple tree today in hopes of harvesting the fruit twenty years from now. But that’s not really the point. It’s about doing things that improve quality of life now – while also protecting our health over the long term.

And yet many people struggle to maintain healthy habits over time. Why is that?
Because people rarely change their behavior unless they understand the reason behind it. When I say, “Exercise is healthy” or “Healthy eating matters,” everyone knows that already. But knowledge alone changes very little. That’s why I try to place things in a different context. I like to describe sleep as “repair,” for example, because that’s exactly what happens during sleep. When someone says, “I don’t prioritize sleep,” it can almost sound heroic – as if sleep were optional. But once you understand that the body is literally repairing itself during that time, people start looking at sleep differently.

Schloss Elmau Valley

Source: Timo Maier

You speak frequently about sleep quality. Why is it so important?
Because the brain clears waste products during deep sleep. In deep sleep, the brain actually shrinks slightly, creating space to flush out metabolic waste products – including amyloid beta, which is strongly associated with Alzheimer’s disease. That’s why simply sleeping eight hours is not enough. What matters is the quality of that sleep. Alcohol, caffeine late in the day, stress, intense evening workouts, or too much artificial light can significantly disrupt deep sleep. Many people never notice this because they don’t struggle to fall asleep or stay asleep – but very few truly understand how well they sleep.

Another major theme in your book is social connection.
Yes, because human beings are fundamentally social creatures. There’s a cruel historical experiment often associated with Frederick II. : orphaned children were provided with food and basic care, but given no physical touch, no closeness, no language. All of the children died. The story shows how essential human connection truly is. Oxytocin, the hormone released through physical closeness, plays a central role here. It takes around thirty seconds of hugging – or about seven seconds of kissing – to trigger a noticeable oxytocin release. Older people in particular often suffer because this closeness is missing from their lives.

Loneliness is now considered a major health risk.
Absolutely. Studies suggest that loneliness can be as harmful as smoking fifteen cigarettes a day. But even without statistics, most people instinctively understand why. When there is no one to get up for in the morning, many things lose meaning. People eat less well, move less, and often lose the motivation to care for themselves properly. That’s why I always say we should invest in the three Fs: family, friends, and folks we don’t know. The last one means remaining open to new experiences and encounters.

Many people associate longevity with high-tech treatments, supplements, and expensive therapies. Is healthy aging a luxury?
Not at all. I would say that eighty percent of what truly matters costs almost nothing. Exercise, sleep, breathing, social connection – these things are fundamentally accessible to almost everyone. The expensive twenty percent is things like biohacks, treatments, and specialized supplements. But many people focus on those because they seem easier. In reality, much less is needed than people imagine. A good pair of running shoes is enough to start moving. Healthy eating doesn’t need to be complicated. Frozen vegetables can sometimes even be healthier and more affordable than fresh produce.

Source: Leopold Fiala

Concert Hall, Hideaway

At Schloss Elmau, longevity is understood less as a biohacking trend and more as a question of mindset. How important are classical music and dancing – in other words, intellectual and emotional nourishment?
Mental wellbeing is incredibly important, and everything that nourishes us emotionally ultimately benefits our health as well. This isn’t only about relaxation, but also about challenging the brain and remaining curious. We now know, for example, that dancing can have a profoundly positive effect on the brain. Waltzing combines movement, coordination, and rhythm in ways that actively engage the brain. A neurologist once told me that even walking twenty steps backward every day is excellent exercise for the brain because it forces us out of familiar movement patterns. Anything that challenges the brain ultimately has a protective effect.

What role does inflammation play in aging?
Inflammation is actually one of the central reasons we age. It is hugely important – and it is influenced above all by two things: nutrition and stress. That’s why it matters so much how we eat, how we live, and whether we move through life with curiosity and joy. But even if you made unhealthy choices yesterday, today offers another opportunity to choose differently. That’s where the real potential lies.

Why are we so fascinated by the idea of living longer?
The desire for a long life – or even immortality – is probably as old as humanity itself. Even in the Middle Ages, people experimented with potions intended to stop aging.
What is new today is that we are beginning to understand why we age. Researchers now talk about the “Hallmarks of Aging” – twelve biological mechanisms believed to explain the aging process. One fascinating example is the phenomenon of senescent cells, often referred to as “zombie cells.” I like to compare them to a supermarket parking lot. Normally, cells constantly come and go, like cars briefly parking and leaving again. Senescent cells, however, simply remain there even after their task has long been completed. They occupy space and release substances that can promote inflammation. Researchers are now investigating ways to eliminate these cells selectively using so-called senolytics. At the same time, we’re realizing that the situation is far more complex than it first appeared. These cells may also have protective functions – for example, helping prevent cancer cells from spreading uncontrollably.

What would you say is the most important mindset behind all of this?
Curiosity. Without question. Children are naturally curious, and at some point that curiosity is often trained out of them. Yet this openness to new experiences is incredibly healthy. People who remain curious usually remain mentally vibrant as well. Perhaps in the end that is the truest form of longevity: not living as long as possible, but remaining open, engaged, and connected to life for as long as possible.