There’s one decade that impacts your health more than any other.

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I am turning 42 next month, and I stumbled across some information that has made me feel, well, anxious, really…

How we live from 36-46 has the biggest impact on our future health.

The Finnish research shows this decade in particular shapes the health we'll experience in the decades to come. Around mid-30s is when we start to lose the ability to get away with unhealthy behaviour.

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Which unhealthy behaviour you might be wondering? Well, there are three in particular: smoking, heavy drinking, and physical inactivity.

Yikes. I definitely don't do enough exercise, and I am known to lean into a long lunch, let's just say. Two out of three ain't bad, right?

The stats.

As part of the Jyväskylä Longitudinal Study of Personality and Social Development, researchers tracked participants over 30 years, revealing some uncomfortable truths about how our choices between ages 36-46 create ripple effects that last decades.

Lack of exercise was especially damaging for physical health. Smoking contributed most to poor mental health, and heavy drinking harmed both.

The effects accumulate, so the longer these behaviours persist, the greater the risk for non-communicable diseases like heart disease and cancer.

Dr Steven Lu, CMO and Co-Founder of Everlab, told Mamamia "This study makes a compelling case for midlife as a decisive period in shaping long-term health. It highlights how health behaviours do not act in isolation but accumulate over decades, influencing both physical and mental wellbeing," he said.

"The striking insight is that the choices made between ages 36–46 carry greater weight than those earlier or later, suggesting that midlife is not simply a continuation of earlier patterns but a turning point in health trajectories."

Why this decade hits different.

So what makes this particular decade so crucial? Dr Lu explained that it's when our bodies fundamentally change how they respond to our lifestyle choices.

"During this decade, the body begins to lose some of its natural resilience. Repair processes slow, hormone levels shift, and the first warning signs of chronic disease often appear," he told Mamamia.

"Unlike in the teens and twenties, poor habits can no longer be absorbed without consequence. At the same time, many people face peak pressures from careers, family, and social responsibilities, which can magnify stress and limit time for self-care and restorative sleep — both critical for long-term health."

This convergence of biological change and life demands makes midlife a period where habits matter more than ever, he said.

Mick Owar, Founder of Primal Recovery, put it more bluntly: "There's an old proverb: 'Before 30, man chases disease. After 30, disease chases man'," he told Mamamia.

"And that's exactly what I see. In your 20s, you can burn the candle at both ends — no sleep, poor food, stress, overtraining — and your body just rolls with it. But from 36 to 46, the cracks from those years start showing. That's when the body begins handing out invoices for the lifestyle you've lived."

The invincibility shield wears off.

Dr Vinay Rane from Melbourne Mothers has witnessed this transition countless times in his career. "As a doctor with more than 25 years' experience, I see daily the great irony of modern health. In our 20s and 30s, many of us treat our bodies like disposable assets — late nights, too much alcohol, cigarettes, questionable diets, even recreational drugs," he told Mamamia.

"We push through with the arrogance of youth, assuming our resilience is endless," he said.

"Fast-forward to 50, and suddenly longevity becomes an obsession. Patients who once laughed at vegetables are now stockpiling supplements, booking infrared saunas, investing in red-light therapy, and lying in hyperbaric chambers to undo the decades of self-inflicted damage."

Dr Rane described this shift as fascinating yet concerning: "This pivot — from reckless neglect to desperate preservation — is one of the most fascinating cultural shifts in health. And it raises a vital question: why don't we value prevention when it matters most?!"

But it's not too late.

Before you spiral into existential dread (like I briefly did), there's genuinely good news. The research shows that interventions and lifestyle improvements — even starting in the late 30s or 40s — can still yield significant health benefits and lower the risk of future disease.

"The good news? It's never too late. I've seen people rebuild health in their 40s, 50s, even 60s. But starting in that 36–46 window is like compound interest — small consistent investments now make the biggest difference later," Owar told Mamamia.

Dr Lu agreed, emphasising that this decade represents opportunity rather than doom. "Far from being too late, midlife offers a critical opportunity where modest but consistent changes can profoundly alter the course of ageing," he said.

"For many, this period is also when gender-specific changes, such as hormonal shifts in women, begin to play a more noticeable role."

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What actually works.

So what should you focus on if you're in this crucial decade? Dr Lu outlined a holistic approach that makes the biggest difference:

• Regular exercise, particularly strength and cardiovascular training

• Balanced nutrition with an emphasis on whole foods

• Prioritising restorative sleep

• Consistent stress management

• Maintaining strong social connections

"There's no magic pill. The key is looking at your individual data, this is where preventive health checks become increasingly important at this stage, offering an opportunity for early detection and tailored intervention," he said.

The power of individual choice.

While the Finnish study provides valuable insights, Dr Lu was careful to note its limitations. The research involved 206-326 Finnish participants born in 1959 in one region, resulting in limited ethnic and cultural diversity.

The study was also based on self-reported behaviours and didn't include data on nutrition, sleep, or stress management.

"The most powerful prevention focuses on the individual, not population statistics. Every person is different — genetics, environment and lifestyle all shape how we age," he explained.

"For women in particular, hormonal changes across life stages add another layer of complexity."

His message was ultimately empowering: "Growing older doesn't have to be a passive decline — it can be an ongoing, modifiable process that you have significant control over. Your choices determine whether later years are characterised by vitality or vulnerability."

The bottom line.

"Health isn't determined by a single moment or decision, it's about the direction your choices take you," Dr Lu said.

Whether you're approaching 36, smack in the middle of this crucial decade, or looking back from beyond 46, the message is clear: your choices matter more than you might think, but it's never too late to change direction.

So while I hope we haven't made you rock back and forth in a corner (I might have for a moment) this news is a roadmap for making the next decade count. Because I for one, want to have many more decades to come.

You can hear more from Dr Steven Lu and how to optimise your health at Everlab.com.auFeature Image: Getty.