The spread of canals and trains grew the U.S. economy in the mid-19th century. But this transportation revolution also had some unanticipated side effects.
A strange thing happens on the way to modernity: people get sicker and shorter.
That’s the “Antebellum Puzzle,” a term for the measurable decline in health of the U.S. population in the four decades ahead of the Civil War, even as urbanization and industrialization sent GDP skyrocketing. Historians have shown that during the economic-boom decades between 1820 and 1860, heights and lifespans shrank for the average American—including white men and women, as well as free black men and women—by as much as an inch.
Why? A new working paper published by the National Bureau of Economic Research presents a compelling clue: By opening up access to larger economic markets, the spread of new transportation networks in the Antebellum Period may have weakened the bodies of Americans who had the freedom to move around. Bigger towns may have been good places to find work, writes the author Ariell Zimran, a professor of economics at Vanderbilt University. But they may have also made people more vulnerable to disease and malnutrition as food prices rose, especially for poorer households. (Elites largely avoided the downturn in stature and lifespans, previous research has found.)
The quickened spread of germs and heightened malnutrition are not a new explanation for this pre-Civil War conundrum. But Zimran’s work may provide the first piece of evidence that the 19th century’s transportation revolution—a rapid build out of canals and navigable waterways in the first half of the century, followed by the spread of the railroad—actually caused it.
This analysis was limited to what happened to white, U.S.-born males who were born in rural parts of the Northeast and Midwest between the 1820s and 1840s. That particular cohort was chosen because it is essentially the only one that has “a sample of health data that is reasonably representative of the population,” Zimran writes in the paper. He drew on 25,567 enlistment records of the Union Army during the Civil War, which include the soldier’s height, age, place of birth, and where the individual enlisted.
This historical data provided Zimran a look at the shrinking statures of otherwise fit men—one of the major indicators of health decline for this period—at the individual level, as well as a way to link it to the local conditions where that individual grew up.
This is where the study should bring out the geography nerds. Zimran then turned to his GIS files, mapping by county all of the new canals, navigable waterways, and railroads that opened up during that period. He then drew in how they most directly linked up major watersheds and cities over the same time period, which allowed him to measure rising access to new markets at the county level.
Matching up these maps to the heights of those thousands of soldiers, and controlling for population and how agriculturally fertile those counties were, Zimran found a significant relationship: As the number of new cities or watersheds to which a county was connected increased, the average stature of the soldiers from there declined by as much as one third of an inch. When their hometowns became more linked to the rest of the country by water or rail, residents of these communities were probably exposed to more disease, higher food costs, and perhaps water and air pollution too, Zimran writes. But no matter the particulars, the sheer presence of transportation links might have caused as much as 65 percent of the height decline behind the Antebellum Puzzle, according to his analysis.
So what? Average heights bounced back after the Civil War; it might not seem to matter much what drove them downwards for a short period of time, beyond the fascination factor of historical sleuthing.
But Zimran’s research points to a trade-off that persists all over the world and into the present day. Nineteenth-century England saw the same sorts of health declines as its transportation networks and economy boomed; today, developing countries such as China and India are experiencing similar effects. Massive road, rail, and airport build-outs have midwifed the economic growth of both of these countries. Likewise, transportation infrastructure is one of the primary ways the World Bank invests in the developing world. These projects have helped lift the financial fortunes of billions of people. But, Zimran writes, policymakers might take into account their ill effects on public health before paving over more untrammeled land.
Some researchers believe there’s a modern Antebellum Puzzle playing out in the U.S. today, too, except with weight instead of height. Rising obesity rates among lower-income Americans track alongside the growth in GDP since the 1970s, with one factor among many being changes in land use and transportation patterns since that time. As the U.S. has sprawled, Americans, especially those living in poverty, aren’t moving their bodies as much. And that’s not the only health issue that tracks with income—cardiovascular disease, diabetes, and infant mortality do, too.
How it is that so many people living in one of the world’s richest countries live in such poor health? Whether during the Civil War or the present, the answer to capitalism’s paradoxical effects might actually be pretty simple: As economies grow, often thanks to transportation, so does inequality.
Laura Bliss is a staff writer at CityLab, covering transportation and the environment. She also authors MapLab, a biweekly newsletter about maps (subscribe here). Her work has appeared in the New York Times, The Atlantic, Los Angeles magazine, and beyond.