Income inequality in the United States has been increasing at a rampant rate over the last 40 years. A recent report from the U.S. Conference of Mayors shows that from 1975 to 2012, the top quintile of earners gained significantly more income than the bottom quintile. In 1975, the top 20 percent of U.S. households accounted for 43.6 percent of the nation's income and the bottom 20 percent accounted for 4.3 percent. By 2012, the gap had widened to 51 percent and 3.2 percent respectively. And although the bottom 20 percent of earners experienced the largest relative decline, all income brackets outside of the top 20 percent saw their share of wealth decrease from 1975 to 2012. In other words, the vast majority of the country's economic growth is going to those who are already wealthy, the middle class is shrinking, and the gap between rich and poor is widening.
There is evidence that people who are of a higher socioeconomic status have a greater likelihood of adhering to health guidelines than those who are not. A striking example of this is the strong correlation between earnings and physical activity. The chart below shows that as income level decreases, so too does the chance that an individual meets physical activity guidelines:
The correlation between wealth and physical activity is not surprising, and likely results from a confluence of factors. For instance, lower incomes neighborhoods are more likely to have safety concerns that make outdoor activity a risky venture and often lack green space and well-kept recreation centers. This issue of neighborhood disparities may have the largest effect on youth, and is probably part of the reason childhood obesity rates tend to be higher in low-income populations.
In addition to living in neighborhoods that are not conducive to physical activity, individuals in the lowest income brackets are often under chronic cognitive stress from the challenges of navigating daily life in financial duress, as well as the lack of autonomy that accompanies poverty. When someone is worried about making rent payments, growing debt, rationing food, and being able to afford medications, ensuring daily exercise becomes trivial at best.
While correlation does not mean causation, the combination of rising income inequality and barriers to physical activity for lower income individuals might explain why physical activity has declined precipitously in some segments of the U.S. population -- particularly those not getting any physical activity at all. A recent study in the American Journal of Medicine that examined leisure time physical activity in adults found that about 45 percent of males and 36 percent of females met guidelines in 1990. This number has dropped a bit over the last 20 years, to 42 percent of males and 30 percent of females. However, what is most striking is the number of American adults who went from "some" leisure time physical activity to "none." The chart below shows that the number of Americans getting no physical activity has skyrocketed -- from 11 percent of males and 19 percent of females in 1990 to 44 percent of males and 52 percent of females in 2010.
As the economic middle class shrinks, so too, does the middle class of physical activity. This is a huge problem because physical activity has far-reaching benefits that promote general productivity in society.
It is widely known that physical activity is good for bodily health, and that it is hard to function optimally in the absence of physical health. Regular exercise has also been shown as a great mechanism to cope with mental health issues like anxiety and stress. This is ironic because the same chronic stress and angst that physical activity may counteract may be preventing people in poverty from exercising regularly. Perhaps this is part of the reason why impoverished areas struggle with elevated levels of violence - residents don't have the opportunity to "blow off steam" via regular exercise.
Physical activity is integral to promoting overall vitality and economic opportunity. Because physical activity is both conducive to an individual improving his or her future economic status, but also can be constrained by someone's current economic status (especially for those in poverty), smart policy ought to address the wealth and physical activity gap in parallel. This could include revisiting wage, tax, and public assistance program policies, as well as considering ways to improve urban design, neighborhood safety, and the presence of meaningful physical activity programs in schools.
Though they may not seem related at first blush, getting people moving physically and economically go hand in hand.
Note: This article was co-authored by Dr. Michael Joyner, who is an anesthesiologist and physiologist at the Mayo Clinic in Rochester, Minnesota