The link between high cholesterol and risk of coronary heart disease has been discussed in medical journals and magazine articles. As such, most doctors suggest that their patients lower their cholesterol by at least one percent. In an article titled "The Exercise & Cholesterol Controversy," appears on the exercise science department page of the University of New Mexico. Authors Len Kravitz, PhD and Vivian Heyward, PhD cite research that links exercise to reduced cholesterol.
Identification
Cholesterol is considered a lipoprotein, which is a fatty substance that is used to build cell membranes, manufacture hormones, synthesize vitamin D and form the bile secretions that assist the digestive process.
Types
Low density lipoproteins, also called LDLs or "bad cholesterol" are produced by the liver. They carry cholesterol and other fats to the muscles, tissues, organs and heart. Very low density lipoproteins are also called VLDLs. They have the same function as LDLs, but they are combined with triglycerides, which is another type of lipid. This combination leads to heavier LDLs, which present an even greater risk for heart disease.
High density lipoproteins, also called HDLs or "good" cholesterol is produced by the liver. They carry cholesterol and other fats from tissues and organs back to the liver. It has been speculated that aerobic exercise can elevate HDLs.
Expert Insight
An article titled "Effects of the Amount and Intensity of Exercise on Plasma Lipoproteins" was published in the "New England Journal of Medicine" on November 7th, 2002. It cites research performed at the Duke University Medical Center.
The research team recruited 111 overweight men and women, who were assigned to participate for eight months in one of three exercise groups. One group performed a high-duration--high-intensity exercise, which was the equivalent of jogging 20 miles a week. The second group performed short-duration--high-intensity exercise which was the equivalent of jogging 12 miles a week. The third group performed short duration-low-intensity exercise, which was the equivalent of walking 12 miles per week. The high-intensity, longer duration group showed the greatest improvements in cholesterol.
Theories/Speculation
An article on the November, 2002 edition of the "Science Blog" features an interview with William Kraus, M.D., who led the Duke University study. Kraus speculates that exercise increases the size of the particles that carry the bad cholesterol to your heart. This prevents them from entering the heart and clogging the arteries.
Prevention/Solution
The Duke University study also had a control group, which did not exercise. The researchers found that the LDL cholesterol levels of this group actually worsened. Leading an active lifestyle may prevent high cholesterol.
