First, a question: When in American history did life expectancy improve the most?

Was it the late 1800s, when anesthesia made surgery easier and far more common? Was it the 1930s, when antibacterial medicines became available? Or recent decades, when CAT scans and heart bypasses proliferated?

The correct answer is: none of the above. While data differ and the statistics aren’t fully reliable, a good bet is that the best answer is the 1940s. In that period, life expectancy increased about seven years.

Indeed, American life expectancy appears to have been longer in 1942, 1943, 1944 and 1945  even as hundreds of thousands of young Americans were being killed in World War II  than it had been when America was at peace in 1940.

A prime reason is that with the war mobilization, Americans got much better access to medical care. Farmers and workers who had rarely seen doctors now found themselves with medical coverage through the military, jobs in industry or New Deal programs.