The conservative German Chancellor Otto von Bismarck proposed a national retirement benefit to satisfy the leftist masses in 1881, setting the retirement age at 70. However, the average life expectancy at the time was about 40. Von Bismarck resigned right after the policy passed, but his legacy remained, and Germany’s retirement benefit became a model for other nations. In 1916, Germany lowered their retirement benefit age to 65.

When President Roosevelt launched the Social Security Act of 1935, 65 was chosen as the national retirement age, although less than 60 percent of American adults lived that long. In modern times, many more people live long enough to access a national retirement fund, often for years, if not decades. The average life expectancy in the United States is 76, even higher in many European countries.

The U.S. national retirement age, or when you can start claiming Social Security benefits, has gradually increased to 67 for those born before 1960. In response, several countries are debating raising the retirement age in an attempt to offset the economic pressures of an aging population and the worry that national retirement benefits won’t be able to keep up for much longer.

From an economic standpoint, a later retirement age perhaps benefits everyone’s bottom line. But putting finances aside, what are the mental and physical implications of raising the national retirement age? One way to answer this question is to look at changes, not in life span but in healthspan, the number of years people are healthy and disability-free. Think of it as your work span.

Gal Wettstein, a senior research economist at the Center for Retirement Research at Boston College, compared age and retirement potential for employment in a study about people’s working life expectancy. He discovered that healthy Americans at age 50 could expect to have almost 23 more years free of disability, plus eight years of living with a disability. This data would suggest that, on average, people’s maximum working life expectancy is 73.

“There’s no doubt that life expectancy is longer, and also, the ability to work has expanded,” Dr. Wettstein said. “Part of that is medical changes and part of that is the nature of work has changed.” In 2020, roughly 45 percent of the American labor force worked in a knowledge-based field, such as management, business and finance, education and health care. In 1935, these types of professions accounted for just 6 percent of the workforce.

Dr. Pinchas Cohen, dean of the Leonard Davis School of Gerontology at the University of Southern California, agreed that from a health standpoint for people in these fields, a retirement age under 65 “makes no sense.” He said, “Even 65 is a 20th-century number.”

For people working in knowledge-based jobs, a retirement age in the 70s is reasonable from a cognitive perspective, too, said Lisa Renzi-Hammond, director of the Institute of Gerontology at the University of Georgia. “Our cognitive faculties we’re able to maintain, usually, pretty well into our 70s,” she said. “If the retirement age is set based on the capabilities or competence of employees, there’s absolutely no reason to have a retirement age in the 60s.”

The initial intent of Social Security, when established in 1935, was to sustain people once they could no longer physically work. But another way to think of federally funded retirement is that it should reward people with a few years of leisure.