There are many things which make it difficult to assess how exercise alone affects cholesterol levels. Total cholesterol levels are lower in persons with high aerobic fitness but it is not conclusively demonstrated that exercise training is the sole reason for total cholesterol reduction. Activities that are more vigorous in nature, such as running programs seem to have more benefit. There are studies that show high intensity training increases HDL levels, which are responsible for taking bad cholesterol away from cells. The most important though is that exercise can reduce body fat and a decrease of body fat is a contributing factor for lowering triglycerides.