If the past is prologue, then U.S. life expectancy may actually increase during this current economic crisis.

That’s right. As counterintuitive as it may seem, we — the people of the United States — seem to get healthier (as a group) when our economy gets sick.

At least, that’s what happened during the 1920s and 1930s, according to a new analysis by University of Michigan researchers Jose A. Tapia Grandos and Ana Diez Roux. They found that life expectancy increased during the deep recessions of 1921, 1930-1933 and 1938, but declined during years of strong economic expansion (1923, 1926, 1929 and 1936-1937).

In fact, during the deepest and longest recessionary period (1930-1933) of what we call the Great Depression, U.S. life expectancy increased by an astonishing 6.2 years, from 57.1 years in 1929 to 63.3 years in 1932. The increase was seen in both men and women and across all racial groups.

Even infant deaths and adult deaths from tuberculosis declined during those years — and this despite evidence of greater malnutrition during the Great Depression.

The only exception to this association between better health and economic slumps: suicide. The study, published in the current issue of the Proceedings of the National Academy of Sciences, found that suicides peaked alongside unemployment in the most recessionary years of 1921, 1932 and 1938. But because suicides represent only 2 percent of all deaths, this increase did not change the overall drop in the death rate during those years.

(We’ve already begun to see this aspect of the Great Depression repeated in our current Great Recession. Late last year, researchers reported that suicide rates in the United States had increased for the first time in a decade.)

What was going on?
Grandos and Roux note in their study that they were looking at the relationship between recessions and death rates for the population as a whole, not for individuals. The mental, physical and financial stress of becoming unemployed — particularly if it involves losing one’s health insurance — can have a devastating impact on a specific person’s health.

Yet, although economic downturns can be harmful to the mental and physical well-being of individuals, they seem to have healthful benefits for the population as a whole. Why is that? Why would life expectancy increase during what Grandos and Roux call “periods of pessimism, shrinking revenues, and social malaise”?

Other research offers possible explanations, say the two analysts. During periods of economic expansion, people tend to work more overtime as well as harder and faster. They also sleep less. These factors increase their stress, and stress is associated with more smoking and drinking. (People working overtime — if they’re paid for it — also have more money to buy cigarettes and alcohol.)

In addition, a booming economy leads to more traffic and industrial accidents — as well as more air pollution. As air pollution climbs, so do deaths from heart attacks and respiratory illnesses.

People also tend to be more socially isolated and to have fewer social supports during economic expansions, due in part to the increased work demands but also, perhaps, to their need to take a job far from family and friends. Social isolation has also been linked to poorer health.

“Overall,” Grandos and Roux conclude, “our results show that years of strong economic growth are associated with either worsening health or with a slowing of secular improvements in health.”

Perhaps we should be careful what we wish for.