Everyone has experienced loneliness at some point in their life.
And one in four adults feel this way some or all of the time, according to the Mental Health Foundation.
Being lonely undoubtedly affects our mental health, but the link between mind and body also can't be underestimated.
While there is no one single solution, understanding the affect it can have on us, and knowing the steps to help prevent, or combat this, can help.
The pandemic and loneliness
Amid the coronavirus outbreak, it was suggested lonely people may develop more severe complications.
Studies show healthy people who spend little time with others are more likely to develop symptoms if they catch a cold than those who are more sociable.
Research has also suggested when people are exposed to cold viruses in a laboratory setting and then placed under “quarantine”, lonelier individuals are more likely to catch the infection.
“[Studies have] not [been] done for [the] coronavirus, but [the results] would likely be the same,” Dr Ruth Hackett from King’s College London previously told Yahoo UK.
“[It’s a] very accurate concern”.
Positive emotions, unlike loneliness, are thought to strengthen the immune response.
This has been seen among extroverted individuals, despite them arguably being exposed to more people who may be infectious.
Loneliness is thought to affect “aspects of the immune system responsible for the production of pro-inflammatory cytokines [immune-fighting proteins]”, according to scientists from Rice University in Houston.
Over-production of cytokines can “generate sustained upper respiratory infection symptoms”.
Mood changes can affect health
At a time when officials were urging us to continue looking after our physical health through exercise amid the coronavirus outbreak, clinical psychologist Dr Lisa Orban worried lonely people would lack the motivation – which may still have lingering affects now.
“Loneliness can also negatively affect one’s outlook on their health and their ability to care for themselves when they do become ill,” she previously told Yahoo UK.
“For example, someone experiencing loneliness might feel that they have ‘nothing or no one to live for’, which can reduce motivation to care for themselves properly and get through their illness.”
Watch: 5 top tips to boost your mental health
Loneliness and a healthy lifestyle
The coronavirus aside, scientists from the University of Bristol previously found lonely people are more likely to take up smoking, get through more cigarettes in a day and be less able to quit.
They wondered if the addictive substance nicotine, “interferes with neurotransmitters such as dopamine”. The release of this feel-good chemical may ease the feeling of loneliness.
Perhaps surprisingly, a 2010 study found loneliness was as bad for health as smoking 15 cigarettes a day.
Scientists from the University Hospital in Essen, Germany, also found loneliness increases the risk of premature death.
After looking at more than 4,000 people over 13 years, they found a lack of social integration raised the risk of heart disease by 44% and the odds of death from any cause by 47%.
“We have known for some time that feeling lonely or lacking contact with close friends and family can have an impact on your physical health”, said study author Dr Janine Gronewold.
“We don’t understand yet why people who are socially isolated have such poor health outcomes, but this is obviously a worrying finding, particularly during these times of prolonged social distancing.”
Brain scans differ in lonely people
While it may sound farfetched, evidence even suggests loneliness affects brain activity.
Scientists from Stanford University carried out MRI scans on 50 volunteers while they thought about themselves, their friends, acquaintances and celebrities.
Results, published in The Journal of Neuroscience, revealed thinking about someone from each category corresponded to a different activity pattern in the medial prefrontal cortex of the brain.
The closer the relationship, the more the pattern resembled that observed when thinking about themselves.
The brain patterns varied among lonelier individuals, however, where activity related to thinking about themselves was markedly different than for the other categories.
The scientists concluded these individuals have a “lonelier” representation of their relationships.
“It's almost as if you have a specific constellation of neural activity that is activated when you think about yourself and when you think about your friends, much of the same constellation is recruited,” said study author assistant professor Meghan Meyer.
“If you are lonely though, you activate a fairly, different constellation when you think about others than when you think about yourself.
“It's as though your brain’s representation of yourself is more disconnected from other people, which is consistent with how lonely people say they feel.”
If you are struggling, the Samaritans are available 24/7 on 116 123.
Watch: How can I improve my mental health?