Why Your Body Feels Different After 45 (And It’s Not Just Age)

Why Your Body Feels Different After 45 (And It’s Not Just Age)

A 2026 study on plant compounds may help explain why the body becomes less responsive as we age

I know it can be frustrating.

You feel like you’re doing the right things. You’re getting your steps in. You’re thinking about protein. You’re trying to optimise sleep and follow the advice that seems sensible. Maybe you’ve added some light weights. Maybe you’ve started juicing regularly or including things like turmeric or greens in your daily routine.

You’re making thoughtful changes.

And yet the results don’t flow the way they used to.

Strength doesn’t increase the same way it did in your twenties. Fat loss feels slower. Recovery takes longer. Energy can feel a little unpredictable from week to week.

It’s very easy to assume this is simply what ageing looks like.

But biology is usually a little more interesting than that.

A 2026 review paper looking at polyphenols and age-related muscle loss highlighted something that helps explain what many people experience in midlife. The researchers were exploring how plant compounds influence the internal environment of the body as we age, and how that environment affects muscle maintenance and metabolic health.

What becomes increasingly clear from this research is that the issue isn’t always effort.

Often, the issue is responsiveness.

I recorded a short video explaining this idea and why it matters so much once we move into our 40s and beyond.

If that resonates with you, the rest of this article goes a little deeper into what the researchers were actually exploring, and why their findings line up so closely with concepts I’ve been teaching for years about inflammation, oxidative stress and the internal terrain the body operates in.

Why the Body Becomes Less Responsive

For many years the conversation around muscle loss focused mostly on protein intake and exercise. Eat enough protein, stimulate the muscle through resistance training, and the body responds by repairing and rebuilding tissue.

And those fundamentals still matter enormously.

But researchers are increasingly recognising that another layer sits underneath those inputs. The body has signalling pathways that determine whether growth and repair actually occur. One of the most important of these pathways is known as mTOR, which acts almost like a cellular switch that tells the body when it’s time to build.

When we lift weights or consume protein, that signal is activated. In younger tissue the response tends to be strong. But with age the same signals can produce a weaker effect. Researchers sometimes describe this as anabolic resistance.

The stimulus is still there. The body simply doesn’t respond as strongly.

This is where the internal environment becomes important.

What the 2026 Study Found

The review paper looked at the role of polyphenols, which are naturally occurring plant compounds found in many fruits, vegetables, herbs and spices. These compounds are known to influence inflammatory pathways, oxidative stress and cellular energy systems.

What the researchers found was that polyphenols appear to support the internal conditions that allow muscle tissue to respond to stimulus.

They don’t directly build muscle. Instead, they appear to influence the terrain in which the body operates. Lower inflammatory signalling, reduced oxidative stress and improved mitochondrial efficiency all appear to play a role in improving how the body responds to exercise and nutrition.

That distinction is important.

The goal isn’t to force growth. The goal is to create conditions where the body is capable of responding.

Why This Aligns With the Triple A Model

If you’ve followed my work for a while, this will probably sound familiar. When I talk about the Triple A model I’m referring to three biological factors that influence how well the body functions day to day.

Inflammation, oxidative stress and mitochondrial function.

When inflammation is elevated, signalling inside the body becomes less efficient. When oxidative stress rises, repair systems have to work harder simply to maintain stability. And when mitochondrial function declines, the energy required for rebuilding tissue becomes more limited.

Improve those conditions, and something interesting often happens. The body begins responding more strongly to the same behaviours that previously felt ineffective.

The effort hasn’t changed. The responsiveness has.

The Five Master Systems Perspective

Muscle health doesn’t exist in isolation. It sits at the intersection of several systems that regulate how the body functions overall.

Hormones influence muscle growth and breakdown. Digestive function determines how well nutrients are absorbed. Detoxification pathways influence inflammatory load. The immune system regulates chronic inflammatory signalling. And mineral balance affects both bone and muscle stability.

These are what I refer to as the Five Master Systems of health.

When those systems are overloaded or under-supported, tissues become less responsive. The body shifts into a protective state where maintaining stability takes priority over optimisation.

The Slow Drift Most People Don’t Notice

One of the reasons this can feel confusing is that the changes rarely happen suddenly.

Health tends to drift gradually.

Muscle mass declines slowly. Resting metabolism changes a little each year. Recovery takes slightly longer. Insulin sensitivity shifts gradually.

None of those changes feel dramatic in the moment, but over time the direction becomes noticeable.

When people sense that shift they often respond by pushing harder. More restriction. More intensity. More effort.

But effort applied into a resistant system rarely produces leverage.

Leverage comes from improving responsiveness first.

A Different Way to Think About Midlife Health

Instead of asking how to push harder, a more useful question might be how to improve the internal conditions that allow the body to respond.

When inflammation is lower, signalling improves. When oxidative stress is reduced, repair becomes more efficient. When mitochondria function well, energy production supports rebuilding and recovery.

The same behaviours that once felt ineffective can begin producing noticeable results again.

And that’s where things start to become interesting, because the body is far more adaptable than most people realise.

The direction of your health is not fixed. Internal conditions can shift, and when they do the body often becomes capable of responding in ways that feel very different from what you may have experienced in recent years.

That idea, that the body moves through periods of resistance and responsiveness, is something we’re going to explore much more deeply in the coming weeks.