Being black in America is not easy. We know this. The stories making headlines — from Michael Brown’s death at the hands of Missouri police to the massacre at a Charleston church that killed nine — are indicative of a problem with far-reaching consequences. Racial discrimination and the acts of violence that have made murder the number one killer of young black men are destroying the health of the broader black community in complicated, but demonstrable ways.

One of the strategies blacks, other minorities, and the otherwise disadvantaged employ to cope with social discrimination and unfair obstacles is to work harder. This sounds quintessentially American and it is, but the phenomenon — dubbed John Henryism for the mythic steel-driver who beat a steam-powered hammer — is also dangerous. Hard work, as countless stress studies have proved beyond a doubt, hurts.

John Henry’s heart gave out right after he won his race against the machine. The man died clutching his hammers.

In the late 1970s, epidemiologist Sherman James came across the phenomenon in North Carolina while studying health disparities across different races. A specific example: James met a black man named John Henry Martin who, through sheer hard work and determination, had managed to escape the sharecropping system and purchase 75 acres of his own farmed land by age 40. Unfortunately, by his 50s, the man suffered from severe hypertension, arthritis, and peptic ulcers. His admirable success came at tremendous cost.

Human biology explains why John Henryism kills. Your body’s response to stress is to release higher levels of certain hormones like adrenaline, which activates the body’s fight-or-flight response, and cortisol, which burns metabolizes fats and carbs into sugar for energy. But these hormones are only meant to be released in special circumstances. If they’re overproduced and released too often, your blood pressure starts to fly off the charts, your heart muscle starts to break down, and your immune system weakens.

And black Americans are more familiar with stress-related illnesses than most other ethnic groups. About 41 percent of blacks in the US have hypertension, compared to 27 percent of whites. Heart failure for blacks under the age of 50 is 20 times higher than for whites. The average life expectancy of blacks is four years lower than the national average — not surprising when you consider what a lifetime’s worth of stress can do to the body.

John Henryism is an important phenomenon to keep in mind when reading about acts of violence directed at minorities and blacks in particular. Dylann Roof set out to kill people, but probably didn’t totally understand the ways in which he could succeed. By inflicting yet more stress on Southern black communities, he managed to do more than immediate harm.

Racism is an abstract concept that does very real physical harm. Acts of terroristic violence do very real harm to non-victims. Prejudices — even the ones that fly proudly at the top of flagpoles — do very real harm. The American conversation on race isn’t just about ideas, it’s about bodies and it’s about death. John Henry won, but he also lost. Proving oneself hurts more than you might think.

Photos via Fibonacci Blue (Flickr)