Being lonely can be bad for your psychological health, but it can also affect your physical health, especially by speeding up your body's aging process.
This is the conclusion reached by a new study, which found that loneliness increases the biological age of people more than regular smoking.
The study used an aging clock to test blood and biometric data from almost 12,000 Chinese adults.
The researchers behind the study, led by biotech company Deep Longevity, said they were surprised to see how much influence psychological factors can have on aging, compared to established physical factors such as smoking.
The measurement method is a statistical model that measures biological age, rather than chronological age, which tells how old a person actually is based on their date of birth.
By looking for a combination of 16 blood biomarkers, seven biometric parameters and the participant's biological sex, the watch created an age prediction.
"It turns out that if a person is recognized by this model as elderly, their molecular aging processes are accelerated. This property can be used to prevent the onset of aging-related diseases or to find ways to slow aging."
The researchers said the most important predictors of age were blood pressure, cystatin C a protein that signals kidney health, body mass index (BMI) and lung capacity spirometry.
After analyzing data from 11,914 Chinese adults, the method determined that smoking added about 1.25 years to aging, but feeling lonely could add 1.65 years to aging.
However, it was not the only feeling that contributed to this acceleration of aging, but a whole psychological group designed to measure well-being that also included fear, hopelessness, depression, dissatisfaction and poor sleep.
Those who had never married were also found to have an extra 0.35 years of age due to their single status, while people living in rural areas had an extra 0.39 years of age.
The authors concluded that given the strong link between psychological states and aging, poor mental health should be recognized as a major driver of aging.