Long-term loneliness can be as detrimental to a person's health as obesity, it has been claimed.
A study of more than 2,000 people aged over 50 conducted by the University of Chicago found that those who spent lengthy periods of time alone were 14 per cent more likely to die early.
That puts loneliness in the same bracket as being overweight and makes it almost as bad as poverty.
As well as affecting their physical health, feeling lonely was found to impact on a person's mental wellbeing. And the issue is growing, with the findings showing that older people are currently spending between 20 and 40 per cent of their time alone.
Professor John Cacioppo, a psychologist and leader of the research, said people have "mythical notion" of retirement, wrongly believing that it is a time to move somewhere in the sun, when staying close to friends and family is really the best thing.
"We find people who continue to interact with cop-workers after retirement and have friends close by are less lonely...it is true throughout the world. I’ve done studies in Europe and China and we are not seeing any differences, regardless of where we look,” he said.
Although many people claim to like spending time alone, lengthy periods of solitude have been linked to a rise in cortisol, a hormone which can increase stress levels and raise the risk of stroke or heart attack.
Professor Cacioppo believes lonely people also suffer because their sleeping patterns are affected by "micro-awakenings", meaning they sleep less deeply and wake several times during the night.
This in turn increases the risk of them feeling fatigued and being diagnosed with depression.
The study adds to a recent survey from the Mental Health Foundation that found 10 per cent of older Brits feel lonely, while a third have a relative or friend they believe to be very lonely.