Why astronauts lose muscle faster and what it can teach us about ageing

In our most recent episode of The Method, Ongaro joined us to explain what astronauts can teach us about staying healthy on Earth.

Why space ageing mirrors desk work

Ongaro draws a direct link between microgravity ("weightlessness" in space) and modern sedentary living. In space, astronauts don't need muscle and bone. There's no gravitational force encouraging their bodies to stay strong, so tissue gradually wastes away.

"The more we become sedentary, the more our lifestyle becomes technologically driven and away from nature, the more we get close to what happens actually to astronauts in space," said Ongaro.

"The first thing that happens is neuromuscular," Ongaro explained when describing the sequence of space ageing. "The second is muscle. The third is bone."

Yet counterintuitively, fitter people lose capacity faster. According to Ongaro, the body perceives the shift from peak fitness to a low-stimulus environment more dramatically and responds accordingly.

Muscle loss might trigger ageing, not the reverse

Conventional beliefs around ageing state that as we get older, we gradually lose muscle. But Ongaro challenges this.

"After having worked with astronauts, I start thinking the other way around," he said. "I start thinking that the ageing process is a consequence of the loss of fitness and muscle mass."

This calls into question what we really mean when we say "ageing," which is likely a more complicated topic itself. Yet the distinction matters because, according to Ongaro, muscle loss triggers a series of changes that comprise the ageing process.

The impact of muscle on overall health is broad-reaching. Muscle mass influences testosterone production, growth hormone regulation, and the balance of stress hormones like cortisol. When the muscles aren't stressed, these processes are all affected.

What works in space reveals what's possible on Earth

Astronauts on the International Space Station exercise for roughly two hours per day. And despite all the factors working against them. Those who maintain their programmes return to Earth with fairly minimal effects.

"If you have a countermeasure program and you actually do it, the impact is pretty acceptable, almost minimal," Ongaro said. "If we would all be having an active countermeasure program against ageing on Earth, the results would be incredible."

How to start your own countermeasure programme

Those of us on Earth aren't fighting microgravity, so we don't need multiple hours of resistance training per day. But what we do need is something we can do consistently.

Ongaro's guidance centres on what he calls the minimum dose. "You should start by introducing the minimum dose that your brain can accept without any complications," he explained.

"It might be 10 minutes per day...if we can make these 10 minutes per day a real habit, then it's going to be much easier to change them into 15, 20, 25, 30."

Relying on willpower alone won't set you up for success. To build habits that stick, Ongaro recommends designing your environment in a way that sets you up for success. For example, this could mean putting your yoga mat where you'll actually see it, or tossing unhealthy foods you want to stop eating.

"How much you manipulate your environment is very, very important for the adoption of new habits," Ongaro said. "Reward, gratification and dopamine production are the engines of any habit and any behaviour."

Takeaway

"Your muscles are your ticket to freedom," said Ongaro. Staying strong isn't just about being active and healthy now: it's about freedom to move, lift, and live fully in the future.

Where to listen

Listen to the full episode with Dr Filippo Ongaro for more on maintaining strength, bone health, and habit formation that sticks.