Older adults who lack family and friends, or who feel lonely despite having others around them, tend to be in poorer physical and mental health, a new study finds.

Researchers found that among roughly 3,000 U.S. adults ages 57 to 85, those with few social connections were less likely to describe their physical health as good or excellent. Meanwhile, those who felt socially isolated — even if they had friends, family and social activities — tended to report poorer physical and mental well-being.

The findings, reported in the Journal of Health and Social Behavior, add to evidence linking social connections to older adults' health.

But they also suggest that older people's actual social support and their perceptions of that support each have independent effects, according to the researchers.

"Most older adults will experience significant changes in their social relationships due to things like retirement and bereavement, for example," said lead researcher Dr. Erin York Cornwell, of Cornell University in Ithaca, New York.

Some people, she told Reuters Health, respond to this by becoming active in social organizations or spending more time with friends and family. Yet some may still end up feeling lonely at the end of the day. On the other hand, some older adults are satisfied with having fewer relationships.

In this study, people's actual social connections were linked to their physical health — which may be related to practical factors, like having someone to drive you to a doctor's appointment or remind you to take your medicine.

But perceptions of social isolation were related to both physical and mental well-being.

"Given that the perception of one's relationships is also important for health," Cornwell said, "older adults' abilities to cope with changes in relationships are crucial."

"Those who are able to adjust to losses of social relationships will fare better than those who feel lonely or perceive a lack of support," she said.

It will be important, Cornwell noted, to try to find out why some adults are able to deal with relationship losses, while others feel isolated even if they have friends or social activities to fall back on.

Feelings of loneliness and isolation may affect older adults' health in a number of ways, according to Cornwell. They can, for example, create stress, lower self-esteem or contribute to depression, all of which may have physical heath consequences — either by affecting a person's lifestyle choices or through direct effects on the body, such as dampened immune system functioning.