The retirement age at 67 is one of the most controversial reforms of the past decades.

While the Left Party, for example, wants to lower the statutory retirement age to 65, it is not only many economists who are calling for retirement even later, with a view to demographic change.

The debates are mostly about money: about pension reductions, the fear of old-age poverty and the financial sustainability of the social systems.

But the question of the correct retirement age extends far beyond monetary aspects.

It also affects health.

Two years ago, for example, a study by the RWI - Leibniz Institute for Economic Research showed for the first time what influence retirement has on the health of older people in Germany. Shortly after retirement, the mortality of men in the lower half of the income distribution who leave the profession at 63 drops by a good one percent. This is not the case with men and women who retire at the age of 65 and belong to the upper half of the income distribution:

Their mortality increases by two to three percent as a result of retirement.

The probable reason: Men who retire at the age of 63 often come from physically demanding or even dangerous jobs; the risks are eliminated in retirement.

In the case of higher earners who retire at 65, on the other hand, the loss of recognition and social contacts through retirement is likely to be in the foreground.

Have a broader discussion about retirement at 67

However, these results do not yet say anything about how retirement will affect the vast majority of people who do not die shortly before or shortly after retirement. Do retired people lose their mentality faster than their peers who are still at work? The question is difficult to answer empirically. Ideally, one would have to randomly assign several thousand employees to different retirement ages - hardly imaginable in practice. In a new RWI study, we therefore use the different regulations for the retirement age in 18 industrialized countries, including Germany, to determine the effects of retirement on mental fitness.

In total, we evaluate surveys of almost 100,000 people. The cognitive performance is measured, for example, with a word memory test. Respondents should memorize a list of ten words. Immediately afterwards they should remember as many words as possible, five minutes later again. The best possible test result in both runs is therefore twenty correctly named words. The test is simple, but has high predictive power for diseases such as dementia.

The study shows that on average retirement has a negative impact on cognitive abilities in old age.

Retirement means that test subjects can say one word less on average in the test within ten years.

This difference is considerable; it corresponds to the age-related deterioration that occurs on average within ten years, regardless of retirement.

In other words: The normal cognitive decline that people experience between around 60 and 70 doubles again when they retire.

Disadvantages of the rigid retirement age

However, there are major differences: people who choose the earliest possible retirement age do not suffer any significant cognitive losses as a result. Those who only retire at the age of 64, 65 or later, i.e. most of the employees, on the other hand, lose mental health more quickly as a result of retirement. People who postpone the end of their professional life for as long as possible lose up to 20 percent of their intellectual capacity in the following years.

The difference could be due to the fact that people who are particularly longing for retirement and who retire early accordingly often have hobbies and are privately active and therefore do not suffer any mental losses as a result of retirement. This should especially apply if your job was comparatively less interesting and challenging. For the vast majority, however, retirement accelerates mental aging. Probably because the job is usually more activity and mental stress than the private life. This should particularly apply to people who decide to retire as late as possible.

The results suggest that the discussion about retirement at 67 should be broadened: Beyond economic aspects, later retirement could have positive effects on the health of most employees.

However, a rigid retirement age hardly meets the various needs - a new reform should therefore be about greater flexibility.

In addition, it will be important to involve retirees more closely in society and to organize retirement more actively.