Turning 40 feels like a milestone – and with life expectancy still hovering around 81 years for adults in the UK, it does indeed mark a halfway point. Undeniably, the body starts to work against us as we enter midlife, and not just by making those unwelcome grunts when we ease into an armchair.

The risk of cancer starts to increase as the cells become more damaged over time; for women the hormonal changes of the perimenopause may begin at this stage. Meanwhile, our body composition alters – after the age of 30 we lose around 3 to 5 per cent of muscle per decade unless we include strength training in our regimes, and midlifers can find their waistline expanding, though whether this is down to the metabolism slowing down, or an increased cheese and wine habit, remains the subject of debate. But lots of these downsides of ageing can be managed or even prevented by lifestyle tweaks; studies show that adopting healthy habits can decrease cancer risk by as much as 40 per cent. So if you’re in your 40s, one of the best things you can do is have a health check-up.

While clinics and hospitals offer plenty of health check for the early signs of stroke, kidney disease, type 2 diabetes or dementia, there are plenty of tests you can do at home, too.

Measure your waist with a piece of string

Leading diabetes scientist Dr Roy Taylor recently said that not being able to fit into the trousers you wore in your 20s can be a sign you are carrying too much fat and are at risk of type 2 diabetes.

Waist size is a vital indicator of health because fat stored around the middle can be especially harmful, building up around organs such as the liver and pancreas, and raising the risk of insulin resistance and metabolic and cardiovascular disease.

But the jean size test is a bit rudimentary. Dr Michael Mosley, who created the 5:2 diet, has a different marker of good health. "Ideally your waist circumference should be about half of your height," he says. "But you don’t need a tape measure – just grab a piece of string that is as long as you are tall. Fold it in half and see if it fits around your waist."

If it doesn’t, don’t panic, but it is something to work on. "Reducing your waist circumference to half your height will likely improve your long-term health and boost your immunity," Dr Mosley adds.

Time yourself climbing the stairs

If you want a quick test to see how your heart is coping, climb four flights of stairs (60 steps) and time yourself. "If it takes you more than one-and-a-half minutes to ascend four flights of stairs, your health is suboptimal," says Dr Jesus Peteiro, a cardiologist at University Hospital A Coruna, Spain, who presented his research – carried out on people up to the age of 70 – at the European Society of Cardiology conference last year.

A recent study published in the journal Jama Network Open found that getting fit in your 40s and 50s lowers the risk of early death by about 35 per cent – and is particularly protective against heart disease.

Check for lumps and bumps

Women of all ages – but particularly those in their 40s and upwards – should check their breasts regularly. Dr Zoe Williams, the GP and broadcaster, recommends doing this "ideally once a month", and says that it’s not just lumps that we should look out for. "There are many different signs such as irritation or dimpling of the skin on the breast or flaky skin in the nipple area," she says. "If you notice any unusual changes, it’s important to contact your GP as soon as possible."

Breast cancer screening is offered on the NHS from the age of 50. It is not recommended before then because "there’s not enough evidence that it would reduce deaths, and the tests have risks as well", says Sophia Lowes at Cancer Research UK.

Other red flag symptoms to have investigated include unusual lumps anywhere on your body, appetite loss, heavy night sweats and blood in stools. "If you do notice something unusual, tell your doctor," Lowes says.

Stand on one leg

The ability to balance on one leg is a strong indicator of longevity and health, according to a study by the Medical Research Council, which tracked 5,000 people born in 1946 throughout their lives. Those who could balance on one leg for more than 10 seconds with their eyes closed, and then to stand up and sit down in a chair 37 times in 60 seconds – or 35 times for women – tended to have a better life expectancy when they revisited them 13 years later.

"Balance is something we take for granted," Dr Mosley says. "It enables you to move confidently through life but unfortunately, our balance deteriorates when you hit your 40s." The brain uses messages from receptors in our inner ear, eyes, muscles and joints to keep us upright. If our balance is off, it can be an overall marker of decline of brain health.

He prescribes "practising standing on one leg once a day as a simple way to improve your posture and balance. When I’m brushing my teeth, I set a timer, and stand on one leg, switching from one leg to the other. Each day, try to increase the number of seconds and try to work up to a minute if possible."

Measure your blood pressure and cholesterol

Nearly 40 per cent of adults have high or borderline high cholesterol, according to NHS statistics, and levels increase with age. It advises asking for a test if you are 40 and over and haven’t had one before, especially if high cholesterol or heart problems run in your family. High cholesterol has no symptoms, so the only way to tell is a blood test.

Blood pressure also rises with age, thanks to a reduction in elastic tissue in your arteries, and again it can be symptomless. "Around 90 per cent of patients have no symptoms," says Dr Nighat Arif, a GP based in Buckinghamshire. "But high blood pressure can have life-changing effects, such as triggering a heart attack or stroke, damaging your kidneys or even losing your vision."

Women, in particular, need to be aware of raised blood pressure; researchers from Norway reported earlier this year that even slightly elevated readings from the age of 40 were a strong risk factor for a heart attack in the next 16 years.

And cutting your cholesterol and blood pressure – through quitting smoking, exercising, losing weight and reducing salt – can drastically reduce the risk.

Touch your toes

Spinal degeneration and back problems become more common after the age of 40, says osteopath Nadia Alibhai. To protect the long-term health of your back, she says keeping flexible is absolutely key.

"In an ideal world, we should be able to touch our toes in our 40s, as it displays flexibility in your lower back, glutes, ankles and hamstrings. Flexibility is needed for proper blood circulation and muscle elasticity; touching the toes helps prevent muscles from contracting and becoming short and tight."

A study published in the journal Heart and Circulatory Physiology found that being able to touch your toes could mean that your arteries are in good shape, too. Researchers found a correlation between poor flexibility and atherosclerosis in a group of people aged 40 and above.

If you can’t get down that far – you need to practise. "If you’re struggling, start with a slow forward fold," Alibhai says. "Stretch upwards and lengthen your spine before folding forwards. Keep your spine straight and if you need to bend your knees, please do. Don’t push yourself too far – slow and steady wins the race."

"I’m seeing so many people with back problems at the moment," says Dr Arif, "and they are usually posture-related from hunching over screens. If you know you can touch your toes, then you are extending the spinal cord and sciatic nerve, and so you know you’ve got good flexibility."

Do a mole check

Your GP is trained to check moles, and you can ask them to do so. However, Dr David Jack, an aesthetic doctor and skincare expert, says: "I would always recommend getting a regular (once yearly) mole check at a specialist clinic once you turn 40.

"Specialist mole clinics do this every day so if there is something unusual that might not be recognised by a GP then it can be quickly diagnosed and treated right away."

The Daily Telegraph

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