A new study of 4,358 older adults in Japan has found that participants who worked out with others at least twice a week had a lower risk of developing cognitive impairment than those who did so alone or not at all.

People with cognitive impairment — which can range from mild to severe — have trouble remembering, learning new things, concentrating or making decisions that affect their everyday life.

“Social isolation is a known risk factor in dementia and has been promoted during the coronavirus pandemic,” said study author Kenji Tsunoda, associate professor of social welfare at Yamaguchi Prefectural University. “We have been focusing on the effect that exercise has on promoting social communication.”

Over the course of four years, Tsunoda and his colleagues followed participants, ages 65 and older, living independently in Kasama, a regional city about 60 miles north of central Tokyo.

A 2017 survey asked about their fitness habits, including how often they exercise alone or with other people such as a spouse, children, grandchildren, friends or a trainer. Based on the responses, participants were split into three groups: non-exercisers, solo exercisers (exercise alone at least once a week) and social exercisers (exercise with others at least once a week).

The researchers obtained cognitive impairment data from a government database. In Japan, the condition is measured by a nationally standardized method known as the Activities of Daily Living Independence Assessment Criteria. Cognitive impairment in the study was defined as having symptoms that interfere with daily life to the point where supervision or care is needed.

At the time of the initial survey, the mean age of participants was 76.9 years, with 51.8 percent being female. A greater proportion of older adults reported exercising by themselves (31.0 percent) than with other people (24.8 percent). Nearly half responded that they do not exercise at all (44.2 percent). Throughout the four years that followed, 7.7 percent of participants developed cognitive impairment.

Older adults who exercised by themselves, however, were less likely to develop cognitive impairment — by about 22 percent — compared with those who didn’t exercise at all. But the preventive link was boosted by the addition of a social element, which showed a 34 percent risk reduction compared with no exercise.

Tsunoda and his colleagues then created a predictive tool based on their findings, called a population attributable fraction, to assess the impact of social exercise on the entire study population. If all participants worked out with others twice weekly or more, the incidence of cognitive impairment would decrease by 29.2 percent, whereas the benefit would be only 15.1 percent for exercising alone, the tool showed.

The results, published in the Archives of Gerontology and Geriatrics in January, suggest that regular social exercise may act as an effective one-two punch against cognitive decline in older adults. Previous research, summarized in a 2020 report on dementia prevention by the Lancet Commission, pointed to 12 modifiable risk factors — including physical inactivity and low social participation — that account for around 40 percent of worldwide dementias.

“The finding that exercising with others is better than exercising alone supports the idea that a range of different lifestyle changes are beneficial and that these may work together,” said Andrew Sommerlad, associate professor of psychiatry at the University College London, a co-author of the Lancet report.

The importance of exercise in preventing and managing age-related conditions is becoming increasingly clear. A recent consensus statement based on the available scientific evidence recommends older adults engage in physical activity to promote health, prevent diseases and treat a wide range of conditions.

“Exercise is not just for the young,” said Mikel Izquierdo, professor of health sciences at the Public University of Navarra in Spain, who was not involved in the research. “Older individuals can also reap the benefits of exercise and should be encouraged to do so.”

Exercise can help prevent chronic conditions such as cardiovascular disease, stroke and diabetes, while also improving longevity, mobility, mental health and quality of life.

In terms of the aging brain, regular exercise promotes improvements in cognitive function, as well as the prevention and reduction of cognitive decline. Physical activity can change the structure of the brain through increases in blood flow and volume, and impede age-related brain tissue loss.

An extensive body of research has also pointed to socialization as beneficial for the aging brain. In a 2019 study of more than 10,000 people, Sommerlad and his colleagues observed that more frequent social contact at age 60 was associated with lower dementia risk over the next 15 years. And a 2019 meta-analysis of 51 studies found that high engagement in social activity and large social networks were linked to better late-life cognitive function.

“Socializing exercises our cognitive function, providing more resilience to late-life decline — a concept known as building cognitive reserve,” Sommerlad said. “Being more socially active may also encourage healthy lifestyle behavior, and reduce stress.”

The Senior Women Moderately Paced Hiking Group gathers at Spruce Mountain Trail in Larkspur, Colo. in November. Mariza Vazquez (third from the right) started the group two years ago. Kathy Kosch (third from the left), a member, says the group has given her a sense of community. (Kathy Kosch)

Mariza Vazquez of Lakewood, Colo., started a hiking group for other women in her age range two years ago. The Senior Women Moderately Paced Hiking Group today boasts more than 1,000 members and offers weekly hikes, along with forest bathing and mindfulness activities.

“There’s a huge benefit of like-minded women meeting each other. What draws us all together is our love of nature and hiking,” Vazquez, 62, said. “It has created some very engaging friendships.”

Member Kathy Kosch, 70, hikes and walks by herself, but being part of the hiking group pushes her to attempt more challenging trails, she said. Not only do the women cheer each other on, hiking with others also provides safety in numbers, making it less likely for people to get lost or injured.

“Being part of this group of diverse, strong women has offered me a sense of community,” said Kosch, a retired nurse based in Golden, Colo. “These ladies are an inspiration. I expand my universe with every hike.”

The World Health Organization recommends that adults 65 and older engage in at least 150 minutes of moderate activity or 75 minutes of vigorous activity per week, along with at least two or more days of muscle-strengthening activity. But only 16 percent of older Americans meet these guidelines.

Izquierdo and other experts believe that physical activity should be prescribed by health-care professionals in an individualized manner, like any other medications. While maintaining an exercise routine for older adults can be challenging, he suggests that group exercise or working out with a partner can help enhance consistency, motivation and enjoyment.

“No matter your age, it’s never too late to start contracting those muscles and reaping the benefits of exercise,” Izquierdo said.