How old are you - really?

“Those with kidney disease, cardiovascular disease, dementia or chronic lifestyle diseases are biologically older than their chronological age,” says Peter Stenvinkel, Professor at the Department of Clinical Science, Intervention and Technology at Karolinska Institutet.

It is now possible to slow down an accelerating ageing process ‒ and lives can be saved when this is achieved. A clear example of this is the reduced risks in intensive care. In intensive care, biological age is a stronger predictor of outcomes than chronological age, explains Peter Stenvinkel.

“I want us in the health care sector to become better at identifying individuals who are on a fast track in their biological ageing process. Then we would provide them with appropriate lifestyle advice and medication to slow down the process,” he says.

Even though one can live for many more years with a chronic illness, it is challenging for the affected individual, he explains.

“Some might live to 75 years old, but biologically they are older, and this affects their quality of life. These patients also cost society large sums of money. Therefore, we need to look at how we can extend the healthy period for these individuals,’ he says.

So, what can we do to slow down the rate of decline? It is not possible to make oneself younger by dressing like the kids Buying back one’s own youth through anti-wrinkle treatments is also not possible. Rejuvenation does not seem to occur from the outside ‒ the inside is all that matters.

The best advice researchers can give today to slow down ageing is to follow the common recommendations for a healthy lifestyle.

We know that exercise stresses the body in a beneficial way.

“Physical activity and maintaining a healthy weight profoundly alter biological age,” says Sara Hägg.

What we eat and how much we consume also seems to play a role. There is substantial evidence suggesting that a plant-based diet can protect against premature ageing, while red meat, especially ultra-processed foods, can accelerate the process,”’ claims Peter Stenvinkel.

An old trick to slow down the biological ageing process is to reduce calorie intake.

“Eating smaller portions and maintaining weight over time is beneficial for metabolic health,” says Sara Hägg.

Receiving a diagnosis and proper treatment also seems to provide a boost in the right direction. Sara Hägg and her colleagues have observed that biological ageing accelerates before a diagnosis of type 2 diabetes. However, once blood sugar levels are managed, the biological ageing process can be slowed.

The same positive effect is seen with medication for high blood pressure.

“If treated with calcium channel blockers, the biological age can decrease by one to two years,” she says.

How old we feel, our psychological age, often aligns with our biological age. Research shows that self-assessed health, on a scale from one to ten, is a good indicator of longevity/lifespan, at least at the group level. However, this can vary significantly at the individual level.

To determine our true internal age, it is not enough to rely on how we feel. Instead, researchers use various tools. The fact that our organs often age at different rates complicates matters. For example, the breasts are often older than the rest of the body in middle-aged women, which could explain why breast cancer is so common.

If one wants a biological age measure that applies to the whole body, one can combine various classic clinical biomarkers, such as blood sugar, blood lipids, blood pressure, lung function and BMI. Sara Hägg recently did this in a study. She found that a higher biological age compared to chronological age increases the risk of stroke and dementia. A 60-year-old with a biological age of 65 has a 40 percent higher risk of stroke and a 20 percent higher risk of dementia than a 60-year-old who is biologically also 60. In the study, which included 325,000 people, the researchers also accounted for other risk factors such as heredity, lifestyle and socioeconomics.

“We have also conducted several studies previously, where we observed connections between accelerated biological ageing and diseases such as ALS and various cancers,” says Sara Hägg.

Another popular method to determine biological age is to look at the so-called epigenetic clocks. This involves taking blood samples and studying how DNA is regulated, i.e. switched on or off, over time.

When Peter Stenvinkel and his research colleagues in Glasgow compared the ageing process in patients with chronic kidney disease to healthy individuals, they used epigenetic clocks. This allowed them to establish that individuals with chronic kidney failure, who require dialysis, age faster than healthy individuals.

“The kidney patients were approximately five years older biologically and had faster vascular ageing,” he says.

However, with a new kidney, the negative spiral was halted.

“We saw that the ageing process slowed down in those who were transplanted,” he says.

In conjunction with the study, the research group also developed a new and more precise clinical test to measure epigenetic age in both healthy and diseased tissue.

Another biomarker for biological age is telomere length. Telomeres are located at the ends of our chromosomes and protect important DNA material. Each time cells divide ‒ and they will do so repeatedly throughout life ‒ the telomeres shorten. The connection between telomere length and biological age is clear at the group level. At the individual level, short telomere length may indicate a higher risk of cardiovascular disease.

When the telomeres are completely gone from the cell, it can no longer divide. It is not dead, but neither is it alive; it is in a state in between, a kind of zombie state. Today, research is ongoing worldwide aiming to try to kill these zombie cells ‒ because it is believed that this could be a key to even longer life.

Zombie cells, or senescent cells as they are actually called, send out inflammatory markers that increase disease processes in the body. The more zombie cells, the more wrinkles ‒ but also increased risks for conditions such as osteoporosis, cardiovascular disease, kidney disease and cancer.

Today, there are companies that offer tests for individuals who want to find out their biological age. How should one interpret such a result?

“The measures are not sufficiently reliable, and if you take several tests, you may get varying results. But if you see the test as a complement to a regular health check-up, it can be useful,” says Sara Hägg.

To try to slow down the ageing, lifestyle changes are essential.

However, sometimes things happen in our lives that are beyond our control. Both external and internal stressors are negative. Mental health issues, such as depression, can, for example, accelerate ageing. The exact reason is unknown, but American researchers have found that longer or more frequent episodes of mental ill health wear down the body more than fewer and shorter episodes.

Natural disasters can also accelerate the aging process. In one study, it was observed that macaques, a type of monkey, that experienced a hurricane aged approximately two years biologically.

“This would correspond to a human ageing seven or eight years due to the stress caused by a hurricane,’ says Mr Stenvinkel.

‘However, just because one has experienced a difficulty does not mean it is hopeless, the speed slows down again once everything settles.

“If you see biological ageing as sand in an hourglass, the sand flows quickly during stress, but when the pressure and stress cease, it flows more slowly again. It's a dynamic process that can change ‒ and improve,” he explains.