Isolation and loneliness faced by millions of elderly as Japanese government struggles to cope with an ageing population. Reuters

Being isolated could suppress the immune system and shave years off your life. Latest studies show that loneliness can be twice as bad for the health as obesity. Scientists from Chicago University believe that lack of socialising with other people can weaken the immune system and therefore lower resistance to viruses. It can also raise blood pressure increasing the danger of heart attacks and stroke.

Tests on women and men over the age of 50 illustrated that immune system genes called CTRA genes were more active in people who said they were extremely lonely. The immune response that fights off viruses was found to be suppressed. Inflammation, a process linked to many health issues such as heart disease were increased.

The study is published in Proceedings of the National Academy of Sciences, which reveals that experiments conducted on macaques showed that a suppressed immune system allowed the monkey version of HIV to grow more quickly in their brains and blood.

Loneliness can also disrupt sleep, causing people to feel tired the next day and then resort to taking sleeping pills. Studies have shown that loneliness increases the risk of early death by 45% and the chance of developing dementia in later life by 64%. Those who have strong ties to family and friends are around 50% less likely to die over any given period of time than those with limited social lives.

Scientists suggest that lonely people try to break the cycle of their isolation by taking part in charity work for social interaction. "You need to start small. Don't focus on trying to find the love of your life or reinventing yourself all at once. Just dip a toe into the water," John Cacioppo, a social neuroscientist said in a MailOnline report.

Richard Lang, MD, chair of preventive medicine at the Cleveland Clinic in Ohio says people need to attend to loneliness in "the same way they would their diet, exercise, or how much sleep they get."

Dog owners are said to feel less isolated. Interestingly, owning a cat, hamster or lizard has no effect, according to researchers. The difference is that dog owners talk to other people while taking their pets for walks in the park.