While reporting on the trend of people working beyond age 65, Harvard Health mentions a couple of studies that suggest continuing to work later in life might be good for you:

A 2016 study of about 3,000 people, published in the Journal of Epidemiology and Community Health, suggested that working even one more year beyond retirement age was associated with a 9% to 11% lower risk of dying during the 18-year study period, regardless of health.

A 2015 study of 83,000 older adults over 15 years, published in the CDC journal Preventing Chronic Disease, suggested that, compared with people who retired, people who worked past age 65 were about three times more likely to report being in good health and about half as likely to have serious health problems, such as cancer or heart disease.

But: “Other studies have linked working past retirement age with a reduced risk of dementia and heart attack.” In particular, workers who have stressful or physically demanding jobs, or who feel burnt out and unfulfilled by their jobs, may suffer from working longer in life.