A patient in their mid-40s came in not long ago for something minor, a script renewal, nothing urgent. We ran routine bloods while they were there. By the end of the consultation, we had found an elevated fasting blood glucose (a measure of blood sugar), borderline blood pressure, and cholesterol that had been quietly drifting in the wrong direction for what was probably years.
They had no symptoms. They felt fine. They exercised a couple of times a week, watched what they ate, and hadn't been seriously unwell in years. By most reasonable measures, they would have described themselves as healthy.
They weren't wrong. They just didn't know what was happening underneath. This is the most common pattern I see in general practice. It is, in essence, what the concept of healthspan is designed to measure.
What is healthspan?
Healthspan is not how long you live. It's how many of those years you live well: independently, functionally, free from significant disease or disability.
The distinction matters more than most people realise. Australians are living longer than any generation before them. But according to the Australian Institute of Health and Welfare's 2024 Burden of Disease Study, Australian men can expect to spend roughly 10 years of their life in ill health. For women, that figure is closer to 12. Despite two decades of medical advances, the proportion of life spent in full health has not improved at all since 2003.
We are adding years, but we are not adding good ones at the same rate.
This is the healthspan gap: the difference between your lifespan (how long you live) and your healthspan (how long you live well). The goal of good preventive medicine is not to extend the first number. It's to extend the second.
The World Health Organisation estimates that 80% of premature cardiovascular disease, stroke, and type 2 diabetes are preventable. Most of that prevention happens not through heroic medical intervention, but through early awareness and consistent lifestyle investment.
"I feel fine": the most common thing I hear, and the most misleading
Feeling fine is not a health assessment. It's an absence of symptoms. Symptoms are late.
By the time most chronic conditions announce themselves, the underlying process has often been running for years. Insulin resistance (the early stage before type 2 diabetes develops, when the body's cells stop responding efficiently to insulin) can build silently for a decade or more before a diagnosis. Bone density can be significantly reduced before a fracture reveals it. Blood pressure can sit elevated for years with no sensation whatsoever.
What I want patients to understand is the sheer number of things that can be happening quietly, in parallel, without producing a single noticeable symptom:
- Muscle mass declining gradually from the mid-30s, reducing physical capacity in ways that are easy to miss for years
- Cardiovascular risk accumulating through cholesterol changes, rising blood pressure, and early insulin resistance
- Bone density falling from its peak at around 30, with no feedback to the person it's happening to
- Visceral fat (fat stored around the organs rather than under the skin) accumulating independent of body weight or what the scales say
- Sleep quality degrading so you get the hours but not the restorative depth, and the physiological effects compound over years
- Chronic cortisol (your body's primary stress hormone) elevated from sustained low-grade stress, driving fat accumulation around the organs and cardiovascular strain that feels like nothing more than being tired
- Early mental health changes (low mood, a background anxiety that doesn't feel serious enough to mention) quietly accelerating physical decline through inflammation, inactivity, and disrupted sleep
- Micronutrient gaps, particularly vitamin D, iron, and B12, that affect energy, cognition, and mood without an obvious cause
Most patients who later develop a preventable chronic disease were eating reasonably and doing some exercise at 40. They just didn't know that "reasonably" had gaps their body was quietly absorbing.
What about people who are active at work?
The physical activity paradox
One of the most consistent things I hear from tradespeople, labourers, nurses, and retail workers is that their job covers their exercise needs. It's a reasonable assumption. The research tells a different story.
There is a well-documented phenomenon in exercise science called the Physical Activity Paradox. A systematic review of 23 studies covering more than 650,000 participants found that while leisure-time physical activity is strongly protective against cardiovascular disease, occupational physical activity does not confer the same benefit. In some studies, high occupational activity was associated with increased cardiovascular risk, not reduced.
The reasons come down to the nature of the activity: low intensity sustained over long periods, repetitive loading, limited cardiovascular stimulus, and insufficient recovery. The body is being used, not built.
Structured exercise works because it applies a specific progressive stimulus (the right intensity, repetition, and recovery) that occupational movement almost never replicates. Being on your feet for eight hours is not the same as two structured sessions of resistance training and aerobic exercise per week. If you're in a physically demanding job, you may need deliberate exercise just as much as anyone else. And you may be carrying more cumulative fatigue when you try.
Why your 30s and 40s are the decade that matters most
The biology of ageing is not evenly distributed across a lifetime. Some things decline gradually and respond well to intervention at any age. Others follow a trajectory that is much harder to change once it's established.
Bone density peaks in your late 20s to early 30s and declines from there. What you do in the decades that follow determines the reserve you have when decline accelerates.
Muscle mass starts declining from approximately 35 without deliberate effort to maintain it. The process is gradual enough to be invisible for years, then suddenly consequential. The patient who finds everyday physical tasks difficult at 70 usually lost the muscle that would have prevented it between 40 and 60.
Metabolic health follows a similar pattern. The body's ability to process glucose efficiently tends to decrease gradually with age, particularly without resistance training and with increasing body fat. The distance between a good metabolic baseline at 40 and a type 2 diabetes diagnosis at 55 is often measured in compounding inaction rather than a single event.
Investing in your health in your 30s and 40s is not about vanity. It is about building a functional reserve: the physiological capacity to absorb illness, stress, and the normal demands of ageing without losing independence. The earlier that reserve is built, the more of it you have when you need it.
Two things that stop people from starting
The most common is genetics. "My father had heart disease, so I'll probably get it too." Family history matters. It does raise your risk. But for most major chronic diseases, including cardiovascular disease, type 2 diabetes, and many cancers, modifiable lifestyle factors account for the majority of risk. Genetics sets a probability. Your choices change the odds. What a strong family history should do is increase how urgently you establish a baseline, not reduce how seriously you take prevention.
The other is timing. "I'm already in my 50s. I've been living this way for 20 years. Surely it's too late." It isn't. The evidence for lifestyle intervention benefit holds at every adult age. The benefit scales with your starting point, not your birthdate. A 60-year-old who establishes a baseline and starts building is in a meaningfully better position than one who doesn't, regardless of the 20 years before.
What measuring healthspan actually looks like
Measuring healthspan does not require a longevity clinic or an expensive panel of advanced biomarkers. It starts with a GP consultation and a set of routine tests that most people have never had done as a deliberate baseline.
In my consultations, I look at things including blood pressure, fasting blood glucose, cholesterol, and waist circumference. Those are the starting points. The fuller picture draws in sleep quality, stress history, movement patterns, family history, and mental health, among other things. There is more besides. None of it is exotic. All of it is accessible through a standard GP appointment.
If you don't know your blood pressure, your blood sugar, your cholesterol, or your waist measurement, you don't have a health picture. You have a feeling.
Interactive tool
How much do you know about your healthspan?
Answer 6 quick questions to find out which areas are worth raising with your GP.
This tool generates awareness, not a diagnosis. Your GP can help you understand what these numbers mean for your specific situation.
Where to start
The most useful thing most people reading this can do is book an appointment with their GP, not because something is wrong, but to establish what normal actually looks like for them.
Understanding your numbers is not a one-time event. It's a baseline. From that baseline, change becomes visible. Risk becomes manageable. The conversation about what to do becomes specific to you rather than generic.
If you're in your 30s or 40s and have never had a deliberate health review, that's the starting point. If you're older, the starting point is exactly the same.
Healthspan is built in ordinary consultations, over years. The earlier you start paying attention, the more of it you get to keep. In an upcoming article, I'll be covering exactly which blood tests are worth getting in your 30s and 40s, and why most of them are missing from a standard check-up.
Ready to establish
your baseline?
A standard GP consultation is all it takes to start building a real picture of your healthspan. New patients welcome.
Common questions about healthspan
Australian health statistics referenced from the Australian Institute of Health and Welfare, Australian Burden of Disease Study 2024. Physical Activity Paradox data: Cillekens et al., Scandinavian Journal of Work, Environment and Health, 2022. World Health Organisation preventive health estimate sourced directly from WHO global cardiovascular disease prevention resources. This is general information only. Your GP can advise on what is relevant to your individual situation.
