"A report by The Hamilton Project at the Brookings Institution finds that stress levels have greatly increased for Americans at all income levels since the 1970s, but especially for low-income groups.
The report doesn’t measure stress as we typically think about it in daily life. Instead, the researchers track 'stress load,' an index of certain biological markers like blood pressure, cholesterol level, and kidney and liver function, that they say are 'associated with long-term physiological strain.' These metrics are strong indicators of a person’s health and mortality, according to the report," Swanson wrote.