The Office for National Statistics reports that chronic loneliness — a feeling of overwhelming isolation coupled with a lack of meaningful relationships affects 3.83 million people in the UK.

The figures also reveal that the most lonely people are under the age of 30 and 16-29 year olds are twice as likely to be chronically lonely than the over 70s.

Chronic loneliness is very different to the kind of temporary loneliness someone might feel when children head off to university, or when a relationship comes to an end… rather, it is an all-consuming, long-term feeling of isolation that drains mental wellbeing.

Loneliness is a significant health problem which, worryingly, has continued to rise after the pandemic.

It has been known for some time that loneliness can be detrimental to health, but only recently have scientists started to look at the reasons why. Alarming new research has found that being lonely can shrink our brains — and increase the risk of dementia.

Researchers at Japan’s Kyushu University studied almost 9,000 men and women aged 65 and over, tallying the results of their MRI brain scans with details of how much regular contact they had with family and friends.

The results, published in the journal Neurology in July 2023, showed those with the least social contact also had the smallest brain volumes, especially in parts such as the hippocampus and amygdala that are linked with dementia. The researchers say it is possible a lack of social contact may accelerate the usual but gradual shrinkage of the brain, which does happen as people age.

Other studies show regular social and/or verbal encounters spark the nerve impulses needed for the formation of new connections between brain cells, which contribute to maintaining brain volume. In May 2023, the U.S. Surgeon General likened the impact of loneliness on health to smoking up to 15 cigarettes a day.

Research shows being socially isolated can cut up to five years from the life of someone over 60, compared with peers who are not lonely, by heightening the risk of conditions such as cancer, heart disease and dementia.

Another study, published in the European Heart Journal (June 2023) looked at cardiovascular disease risk over a ten-year period in 18,509 adults in the UK with type 2 diabetes. Type 2 diabetes itself presents a major risk of heart attack and stroke as it can lead to circulation damage. But the study also revealed there were even greater risks if those affected also lived an isolated existence, without friends and normal social contact.

But how can feeling lonely of life have such a catastrophic effect on physical health?

One way is that when the body responds as if it’s in danger, it releases the hormone cortisol, which increases heart rate and blood pressure. Thus we are put in the fight or flight mode. Chronic loneliness can cause the kind of persistent stress that means the cortisol response is permanently switched on. Constant exposure to raised cortisol can increase blood pressure, blood glucose levels, cholesterol and triglycerides — all harmful fats in the blood.

A 2016 study published in the journal Heart, by researchers at Newcastle University, linked loneliness to a 30% increase in the risk of stroke or the development of coronary heart disease.

In short, stress release hormones such as adrenaline, which make the heart race and blood pressure increase. Other mechanisms are still under investigation… for instance, some people feel lonely even when surrounded by others, so scientists are now looking into whether loneliness and social isolation have other effects.

According to a 2020 study published in Scientific Reports, being lonely or socially isolated can lead to walking or standing up more lowly and social isolation can lead to poorer balance, All the evidence suggests that getting out and seeing people is the answer.

Psychologists at Stirling University found one key to levels of loneliness was physical touch with a friend or loved one — not just being in their company. The results, published in June 2023 in Scientific Reports, found that even among cohabiting couples, feelings of loneliness declined when there was regular physical contact from just holding hands.

Some old-school pastimes may also help. In a U.S. study from Millersville University Pennsylvania and published in the Journal of Evidence-Based Social Work in July 2023, writing letters to friends was highly effective at combating loneliness and isolation and is very different from emailing and texting.