"On the other hand, lifestyle interventions not only reduce the risk of developing these chronic diseases in the first place - they mitigate the need for medical interventions and improve quality of life overall." Professor Robert Thomas, one of Britain's leading oncologists and author of How To Live

Every winter, there are a few things many of us routinely check around the house.

If a radiator is cold at the top, we bleed it. If the boiler pressure has dropped, we top it up. If something starts making an unfamiliar noise, we investigate.

We don’t wait for the heating system to stop working completely before paying attention. We notice the early signs that something isn’t working as efficiently as it should and do something about them.

Yet when it comes to our own health, we can be remarkably good at doing the opposite.

Our blood pressure creeps upwards. Our waistline gradually expands. We start waking tired despite spending enough time in bed. A blood test shows our glucose is heading in the wrong direction. Our knees, hips or shoulders seem to ache more often.

And it’s very easy to think:

“I suppose this is what happens when you get older.”

But there is an important difference between something becoming more common with age and it being an inevitable consequence of ageing.

Many of the changes we associate with getting older are influenced by factors we can do something about.

That makes midlife an important time to pay attention to the signals our bodies are giving us - not because we need another thing to worry about, but because noticing a change early gives us an opportunity to respond.

Here are five I think are particularly worth knowing about.

1. Your blood pressure is creeping upwards

High blood pressure is remarkably easy to ignore because most of the time you can't feel it.

You can be walking around, working, exercising and getting on with everyday life without realising that your blood pressure is higher than it should be.

That's one reason knowing your important health numbers matters.

Blood pressure is the force exerted by circulating blood against the walls of your arteries. Persistently high pressure puts additional strain on those blood vessels and is a major risk factor for heart disease and stroke.

It's important for your brain too.

Although your brain accounts for only a small proportion of your body weight, it has an enormous demand for oxygen and nutrients and depends on a healthy blood supply to provide them. Over time, high blood pressure can damage the small blood vessels within the brain and is associated with an increased risk of cognitive decline and vascular dementia.

Blood pressure does tend to increase as we get older as our arteries become stiffer. But that doesn't mean we should simply shrug our shoulders when the numbers start rising.

What can you do today?

Start by knowing your blood pressure.

If you haven't had it checked recently, you may be able to have it measured at your GP surgery or local pharmacy, or you can use a validated home blood-pressure monitor.

Regular physical activity, limiting added sugar to no more than 30g a day, taking steps to reduce stress, not smoking and keeping alcohol within recommended limits can all support healthier blood pressure.

Even something as straightforward as taking a brisk walk today is a worthwhile place to begin.

If your readings are consistently high, speak to your healthcare professional. Lifestyle changes can make a substantial difference, but high blood pressure shouldn't be self-diagnosed or ignored.

2. Your blood sugar is elevated

Another health number worth knowing in midlife is your blood glucose.

When we eat carbohydrate-containing foods, they are broken down into glucose, which enters our bloodstream. Our pancreas responds by producing insulin, which helps move glucose out of the blood and into our cells where it can be used for energy.

Problems can develop when our cells become less responsive to insulin.

The pancreas initially compensates by producing more of it, but over time blood glucose can begin to rise. This progression can happen for years before someone is eventually diagnosed with type 2 diabetes.

That's why a result showing that you're in the prediabetes range shouldn't simply be viewed as “I'm not diabetic, so everything is fine.”

It's useful information.

Persistently elevated blood glucose and insulin resistance are associated with damage to blood vessels, inflammation and an increased risk of cardiovascular disease. Type 2 diabetes is also associated with a greater risk of cognitive decline and dementia.

The encouraging part is that this is an area where lifestyle can have a powerful influence.

What can you do today?

Start by finding out your most recent HbA1c result if you've had blood tests.

HbA1c provides an indication of your average blood glucose over the previous two to three months, making it useful for identifying prediabetes and diabetes.

Then look at your next meal.

Instead of thinking about everything you need to stop eating, ask:

Where are the protein, fibre and whole foods?

Vegetables, beans, lentils, nuts, seeds, eggs, fish, meat and other minimally processed foods can form the basis of meals that are more satisfying and have a different effect on blood glucose than meals dominated by refined carbohydrates like white rice, white pasta, white bread and potatoes.

There's another surprisingly simple strategy.

Take a short walk after eating.

Your muscles use glucose for energy, so moving after a meal can help your body manage the glucose entering your bloodstream.

You don't have to transform your entire diet today. Start with your next meal and your next walk.

3. Your waistline is expanding

“Middle-age spread.”

We've even created an affectionate name for it, which perhaps says something about how inevitable we've come to believe it is.

Body composition certainly can change as we get older. Hormonal changes, declining muscle mass, reduced activity and changes in metabolism can all play a part.

But where we store fat matters.

The fat immediately beneath our skin is called subcutaneous fat. Visceral fat, on the other hand, accumulates deeper inside the abdomen around our internal organs.

This isn't simply stored energy.

Visceral fat is metabolically active and is associated with insulin resistance, inflammation, high blood pressure, cardiovascular disease and type 2 diabetes.

So an expanding waistline isn't primarily an issue of appearance.

It's a health signal.

And that's why I prefer to think about waist measurement rather than becoming overly focused on the bathroom scales.

What can you do today?

Get a tape measure and measure your waist in centimeters.

No judgement. You're simply gathering information.

Then calculate your waist-to-height ratio; divide your waist measurement in centimeters by your height in centimeters. It should ideally be under 50%.

Then think beyond simply “I need to lose weight.”

Ask instead:

“What could I do to improve my body composition?”

Walking more is valuable, but maintaining and building muscle becomes increasingly important as we get older too.

Muscle isn't just useful for carrying shopping, climbing stairs or getting up from the floor. It's metabolically active tissue and plays an important role in glucose regulation.

That makes regular resistance exercise - whether that's weights, resistance bands or appropriate bodyweight exercises - an important investment in healthy ageing.

4. You're sleeping poorly

Sleep patterns can certainly change as we get older, but our need for restorative sleep doesn't simply disappear.

While you sleep, some remarkably important things are happening.

Your brain is consolidating memories and processing learning and information from the day. Sleep also supports immune function, hormone regulation, appetite regulation and metabolic health.

During sleep, the brain's waste-clearance system also becomes particularly active, helping remove metabolic waste products that have accumulated.

In other words, sleep isn't wasted time. It's essential maintenance.

What can you do today?

Ask yourself: “What's most likely to be stealing my sleep?”

It could be

• Caffeine late in the day.

• Alcohol in the evening.

• Scrolling on your phone in bed.

• An irregular sleep schedule.

• A bedroom that's too warm.

• Stress that won't let your mind switch off.

Choose one thing to experiment with tonight.

There is another potential sleep problem that's particularly important not to dismiss: sleep apnoea.

If you snore loudly, someone has noticed you stop breathing during the night, or you're consistently exhausted during the day despite apparently getting enough sleep, speak to your healthcare professional.

You can spend eight hours in bed without getting eight hours of restorative sleep.

5. You've learned to live with chronic joint pain

“My knees aren't what they used to be.” Have you said that recently?

Some wear and tear within our joints is undoubtedly associated with getting older. But persistent pain shouldn't automatically be written off because you've reached your 50s or 60s.

Joint pain can have many causes, including previous injuries, osteoarthritis, inflammatory conditions and other health problems. Persistent, worsening or unexplained pain deserves proper assessment.

There's another reason I think this matters so much in midlife.

Pain changes behaviour.

Your knee hurts, so you stop taking the longer walk.

You become wary of stairs.

You stop playing a sport you once enjoyed.

You sit more.

Gradually you lose some strength and fitness, movement becomes harder, and you become even less inclined to move.

The problem can create its own domino effect:

Pain → less movement → reduced strength → poorer fitness → greater difficulty moving → even less movement.

Maintaining our ability to move matters enormously if we want to remain active and independent as we get older.

What can you do today?

Ask yourself:

“What have I stopped doing because of this pain?”

If persistent pain has gradually reduced your activity, don't simply assume you have to accept that.

Talk to your GP, physiotherapist or another appropriate healthcare professional about what's causing it and what forms of movement are suitable for you.

Sometimes the answer isn't to stop moving altogether, but to find a different way of moving while the underlying problem is addressed.

These warning signs are more connected than they appear

One of the most interesting things about these five signals is that they don't necessarily exist independently.

Imagine someone who isn't sleeping well.

Poor sleep can affect appetite and blood-sugar regulation. They wake exhausted, so they're less inclined to exercise. They're more likely to reach for quick-energy foods. Their weight gradually increases, particularly around their middle.

As their fitness declines, movement becomes harder.

Perhaps their joints begin hurting more.

So they move even less.

Meanwhile, their blood pressure and glucose continue moving in the wrong direction.

One problem begins feeding another.

But here's the part I find much more encouraging.

The domino effect can work in the opposite direction too.

Improve your sleep and you may have more energy to move.

Move more and you help your muscles use glucose.

Build and maintain muscle and you support your metabolic health and physical independence.

Improve your diet and you may find it easier to manage your weight.

Lose excess abdominal fat and other health markers may begin improving too.

You don't necessarily have to fix everything at once.

Sometimes changing one thing makes the next thing easier.

What have you been putting down to age?

Perhaps that's the most useful question to take away.

What have you noticed changing over the past few years that you've quietly accepted as part of getting older?

Some changes are, of course, part of getting older. And sometimes there will be medical reasons for symptoms that lifestyle changes alone cannot resolve.

But we shouldn't confuse common with inevitable.

You don't need to overhaul your entire life this weekend.

Instead, become curious by asking yourself:

• What is my body telling me?

• Is there something here worth investigating?

• What's one thing I could do today that would move my health in a better direction?

Then start there.

Just as we don't wait for the heating to break down before giving it some attention, we don't have to wait for a major health diagnosis before investing in ourselves.

Midlife can be a valuable opportunity to notice what's changing, understand our risks and make adjustments while there's still plenty of road ahead.

The earlier we pay attention, the greater the opportunity we have to influence what happens next.