Many factors influence cholesterol levels including diet, family history, body weight, and even hormones. But when people start an exercise program, good HDL cholesterol levels begin to rise within a few weeks.

Exercise also has another big benefit. It changes the makeup of the cholesterol particles themselves, making them less dangerous to the heart. It's good news to hear that exercise can create these positive changes regardless of diet and body weight, according to a study published in the New England Journal of Medicine.

Researchers found that it was the amount of exercise that brought about these changes. Many people think they have to exercise vigorously, but that was not found to be the case. The length of time spent in exercising was more important.

The fact that these benefits came from exercise alone is significant. They were not from weight loss as some other studies assumed. That means that exercise decreases cholesterol problems even in people who are overweight.