Studies show that single people have shorter life expectancy than their married peers. Photo: Li Hao/GT

In the year that has passed since breaking up with his girlfriend, 25-year-old Li Qianqi has completely let himself go.

"Being a single man is really different," said Li, sighing. "Over the past year, I've put on over 15 kilograms, and my face has become blistered with acne."

Although Li and his ex-girlfriend, surnamed Zhou, lived in different cities, with Li in Beijing and Zhou in Zhenjiang, Jiangsu Province, being in a relationship gave Li's life a sense of order and purpose.

While still together, Li would organize his time during the day so he could spend his evenings chatting or playing computer games with Zhou online.

He paid attention to his grooming and his physique, ostensibly in order to please her. Zhou, a stickler for routine, would promptly turn in for bed at 11 pm each night. Li would go to sleep too.   

Since going their separate ways, such habits have fallen to the wayside, and Li's life has fallen into disarray.

 "I read a scientific report of some sort saying that single people tend to have more health problems, which makes sense to me," said Li.

The report Li is referring to is a study analyzing the correlation between bachelorhood and life expectancy, published in the American Journal of Epidemiology in 2011.

With a total sample size of around 500 million people, among the study's findings was that single men are likely to die between eight to 17 years earlier than their married counterparts, while single women face the prospect of death seven to 15 years earlier than their wedded peers.

The study, which caused a stir in the mainstream media when it was initially published, has received renewed attention in the wake of Singles' Day last month in China.

Last year, the National Population and Family Planning Commission released a report indicating that there were 249 million single people in China over the age of 18.

The survey incited considerable public anxiety in a country where marriage has traditionally been seen as prerequisite to entry into adulthood.

Among the factors leading to shorter life expectancy among singles are unhealthy lifestyle habits and a higher risk of depression. Photo: IC

Lifestyle habits of the lonely

Now single, Li usually does not sleep until the wee hours. He plays computer games or watches videos online until 2 or 3 am, and then gets up late the next day, often skipping breakfast. When they were still together, it was Zhou who urged Li to have breakfast each morning. 

A study conducted by the Harvard School of Public Health published in US health journal Circulation last year showed that men who regularly skipped breakfast faced a 27 percent higher risk of having a heart attack or dying from coronary disease. Similarly, irregular sleep patterns have long been linked to lower life expectancy.

"I play League of Legends [a multiplayer online video game], and the people who play with me always joke that everyone who plays the game must be single, or else they would be spending time with their girlfriend rather than seeking companionship through a computer game," said Li.

"Playing computer games is just a way to distract myself so I don't feel so lonely."

Li also turned to alcohol to cope with his breakup, and stopped going to the gym. "[My ex-girlfriend] told me she dislikes men who are fat, so I went to the gym," said Li. "Now it's all okay, because I don't need to please her anymore."

Du Shengxiang, a psychologist who specializes in relationship and marriage counseling, said it is easier to develop unhealthy lifestyle habits when living alone.

"Couples often supervise each other to live a healthy life," said Du. "For single people, it's a lot harder."

Solitude sickness

Another reason for single people's greater risk of mortality, said Du, was the attendant mental stresses that came with being alone.

Du said that those who remained single past the socially-defined norm for the ages of marriage were at greater risk of depression and anxiety. 

 "Although emotional problems are quite common among young people, being single for a prolonged period of time, and constantly trying to suppress the emotions that come from being lonely, can lead problems such as depression, anxiety, and insomnia," said Du. "Perhaps most worrying is the fact that many single people who have been alone for a long time say that they've lost the ability to love and forgotten how to deal with another person in a relationship."

Du said that many of his patients have told him that the source of their mental anguish is their solitude, which has led them to feel as if they are unable to love.

"I think this inability to love is a mental problem, which manifests itself in the fear of intimacy," said Du. "Even for those who voluntarily choose to be single, the pressures exerted by society to be in a relationship can be difficult to deal with."

In addition to psychological problems that can arise from remaining single, some doctors said that the lack of sexual intercourse could lead to physical health problems. 

Guo Jun, director of the andrology (male reproductive health) department at Xiyuan Hospital under China Academy of Traditional Chinese Medicine, said that long-term abstinence as a result of being single could have a detrimental effect on health.

"Living without sex for a long time can lead to prostate problems," said Guo.

For women, it is a similar story. In a report published in the Nandu Daily in 2010, Guan Ting, a gynecologist and obstetrician at Guangzhou Military Hospital, said women who do not give birth are at higher risk of breast cancer and cervical cancer.

A question of lifestyle

A number of people have spoken out against the sweeping generalizations being made as a result of the study. While the study may point to a correlation between being single and living an unhealthy lifestyle, the inference that being single necessarily leads to an unhealthy lifestyle is incorrect, critics say.

Such objections are supported by David Roelfs, assistant professor of sociology at the University of Louisville and the study's lead author.

In an interview with NBC News in 2011, Roelfs took pains to point out that the study was about "probabilities, not certainties," and that it didn't look into the underlying reasons for the higher mortality risk for singles.

"The last thing we want is for some single person to say 'Oh my God, I'm going to die young," said Roelfs in the report.

"I think the claim [that being single results in an earlier death] is completely absurd," said Liu Longhui, a 29-year-old financial worker who has been single for more than three years.

"I lead a very healthy lifestyle, far healthier than many married couples I know."

Liu said that single people frequently have more free time and flexibility, giving them the opportunity to look after themselves properly and to improve themselves.

"Instead of accompanying a girl on a shopping trip, I can spend that time exercising and getting fit," said Liu.

"Of course, it comes down to what you do with that free time. If you spend all your free time at home playing computer games and eating junk food, then probably you will die younger."

Liu also made mention of the fact that not all married couples were happy. He said that two of his married friends quarreled every day, leading to stress and diminishing their quality of life.

A 2011 study published in the Journal of Health and Social Behavior indicated that the mortality gap between singles and people in married couples is closing.

"I think the view that single people are less healthy is not always true," said Wang Gudao, a professor at Anhui University of Chinese Medicine.

Wang said that whether single or not, as long as people adhered to the four cornerstones for a healthy heart advocated by World Health Organization - diet, regular physical activity, no tobacco, and a supportive psycho-social environment, they would most likely have long life expectancy.

"If you choose to be single because you find it makes you happier, then it makes sense to remain single," said Wang. "If you're forced to be single and you have to endure it for a long time, then it's possible that this might lead to health problems."