Regular exercise appears to modestly increase levels of high-density lipoprotein, or "good," cholesterol, according to a meta-analysis study in the May 28 issue of Archives of Internal Medicine, one of the JAMA/Archives journals.
A low level of high-density lipoprotein cholesterol (HDL-C) is an independent risk factor for cardiovascular disease, the leading cause of death worldwide, according to background information in the article. There is strong evidence that individuals who are more physically active have higher HDL-C levels. "Thus, the value of regular aerobic exercise in increasing serum [blood] HDL-C level and in reducing the risk of cardiovascular disease has received widespread acceptance," the authors write. "In contrast, results of aerobic exercise studies vary considerably, depending on the exercise program (e.g., duration, intensity or frequency) and characteristics of subjects at baseline."
Satoru Kodama, M.D., of Ochanomizu University, Tokyo, and colleagues performed a meta-analysis of 25 articles reporting the results of randomized controlled trials that were published between 1966 and 2005 and assessed the effects of exercise on HDL-C. To be included in the analysis, the studies had to evaluate aerobic exercise in adults with an average age of 20 or older, specify HDL-C measurements at the beginning and end of the study, have a length of at least eight weeks, and randomly assign some participants to a group of exercisers and others to a control group of non-exercisers.
The 25 articles analyzed included a total of 1,404 participants with an average age range of 23 to 75 years and an average study period of 27.4 weeks. The exercise groups were told to exercise for an average of 3.7 sessions per week at an average of 40.5 minutes each, burning an average of 1,019 calories per week.
In all the studies combined, HDL-C increased by an average of 2.53 milligrams per deciliter in the exercise groups. The minimum
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