Regular Exercise Helps Keep Inflammation in Check

Source: Tufts University
July 16, 2002 (Reviewed: July 16, 2004)

Numerous studies have shown that physical activity lowers cardiovascular disease risk, although the mechanism is not fully understood. One possibility is that exercise reduces the inflammatory process, a marker for coronary heart disease. Researchers from Emory University in Atlanta examined the relationship between physical activity, inflammation, and coronary heart disease in a recent report in the Archives of Internal Medicine.

Looking at the effect of exercise

Data on 3,638 healthy adults who participated in the National Health and Nutrition Examination Survey from 1988 to 1994 (NHANES III) were used for the present study. Researchers asked how often they engaged in activities such as walking, dancing, gardening, and weight lifting in the preceding month. Blood tests measured serum C-reactive protein (CRP) and plasma fibrinogen levels, and white blood cell (WBC) counts, each an indication of inflammation that is associated with coronary heart disease (CHD) risk.

Multivariable adjusted logistic regression models were used to determine whether CRP levels, WBC counts, and fibrinogen were influenced by frequency of physical activity. Exercise was categorized by the amount (sessions) per month: low (0-3 times), medium (4-21 times), or high (22 or more times). Elevated levels of the inflammatory markers were defined as CRP >/=0.70 mg/dL, WBC >/=9,550 /mL, and fibrinogen >/=373 mg/dL.

Physical activity lowered markers of inflammation

Physical activity influenced CRP levels and WBC count even after adjusting for other factors such as cholesterol and blood glucose levels, body mass index, smoking status, and dietary patterns. Those who exercised the most had less inflammation, according to CRP levels, than those in the lowest exercise group (Odds Ratio [OR]: 0.63, 95% CI: 0.43-0.93, p for trend =0.02). The same amount of exercise had a statistically significant effect on WBC count (OR: 0.59, 95% CI: 0.41-0.84, p for trend =0.006). However, a 'medium' amount of exercise did not significantly alter CRP levels or WBC counts. Exercise frequency did not affect fibrinogen levels.

How it works

While strenuous exercise can cause muscle damage and increase inflammation, there are plausible mechanisms by which physical activity may also reduce inflammation. Obesity is associated with inflammation, and exercise may help control inflammation through weight loss. Alternately, the antioxidant effect of exercise may be the key to a decreased inflammatory response.

Advice for patients

Although exactly how physical activity reduces coronary heart disease risk remains to be explained more fully, it clearly has a beneficial effect. Further study may clarify the most effective exercise duration and intensity for maximum health benefits. However, in the meantime the recommendation is at least 30 minutes of moderate activity on most, preferable all, days of the week.

Source

• Relationship between physical activity and inflammation among apparently healthy middle-aged and older US adults. JL Abramson, V. Vaccarino, Arch Int Med , 2002, vol. 162, pp. 1286--1292

Related Links
Healthy Lifestyle Can Reduce Women's Heart Disease Risk
Tackling Coronary Heart Disease Risk Factors
Coaching Your Patients to Exercise
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