Researchers found that physical fitness was associated with lower levels of an inflammation marker associated with heart disease, known as C-reactive protein. The effects of fitness on lowering C-reactive protein were particularly prominent in people with the metabolic syndrome.
One in four adults in the U.S. has signs of metabolic syndrome, which include high blood pressure, elevated blood sugar, high cholesterol, and obesity. Studies have shown that the risk of heart disease, heart attack, and stroke is nearly three times higher in people with metabolic syndrome than those without this group of risk factors.
"Our study shows that fitness is an important determinant of C-reactive protein levels in subjects with the metabolic syndrome," says researcher Doron Aronson, MD, of the Rambam Medical Center in Haifa, Israel, in a news release. "Subjects with the metabolic syndrome who maintain a high fitness level have markedly lower C-reactive protein concentrations compared to those with low fitness levels."
Researchers say that based on these results, increasing exercise and improving physical fitness may be a simple and effective way to lower C-reactive protein and the risk of heart disease-related complications.
Exercise Lowers C-Reactive Protein
In the study, researchers assessed the physical fitness levels of 1,640 people and measured their C-reactive protein levels. Previous studies have shown having high levels of C-reactive protein in the blood can increase the risk of heart attack and stroke in people with the metabolic syndrome.
The results appear in the Nov. 16 issue of the Journal of the American College of Cardiology.
About 20% of the participants had metabolic syndrome. Researchers found that people with metabolic syndrome who were physically fit had much lower C-reactive protein levels than those who were inactive.
Among the most physically fit people with metabolic syndrome, the average C-reactive protein level was half as much as the average level among the least fit (4.62 milligrams per liter vs. 2.2 milligrams per liter).
In addition, the effect of physical fitness on C-reactive protein levels was more pronounced in people with metabolic syndrome than in healthy people.
"We were surprised by the large effect of fitness levels on C-reactive protein in subjects with the metabolic syndrome," says Aronson.
The study shows that physical fitness has a positive influence on C-reactive protein levels, regardless of a person's other risk factors. Based on these findings, researchers say people with metabolic syndrome should be encouraged to increase their level of physical activity in order to reduce their risk of heart disease and stroke.