Cholesterol is a waxy substance that circulates in your blood and serves a number of functions in your body. Health authorities divide cholesterol into two categories: high-density lipoprotein and low-density lipoprotein, or HDL and LDL. HDL is considered good cholesterol because it removes excess harmful cholesterol from your blood that can contribute to heart disease. While you want your LDL cholesterol to be low, your HDL cholesterol should be high. Being aware of what can decrease your HDL cholesterol levels is important to keeping your heart healthy.
Smoking
Smoking can cause inflammation that decreases your HDL cholesterol levels. If you quit, you can improve your HDL levels by 10 percent, according to MayoClinic.com. Because quitting can be challenging, talk to your physician, who may recommend successful quitting strategies and support groups.
Obesity
Excess calories can cause you to gain weight, and these calories often come from saturated fat sources like animal fats, oils and preservatives that can lower your HDL cholesterol. For every 6 lb. you lose, you can increase your HDL cholesterol by 1 mg/dL, according to MayoClinic.com. By making a commitment to eating a diet lower in fats, for example by trimming visible fat from your foods, you can increase your HDL cholesterol.
Physical Inactivity
A lack of physical activity can reduce your HDL cholesterol level. By making healthy lifestyle changes to lose weight, including doing more physical activity, you can potentially increase your HDL cholesterol. If you have been sedentary for some time, talk to your physician before beginning an exercise program. You may wish to incorporate short bursts of low-impact exercise, such as walking, biking or using an elliptical machine, to lose weight.
Trans Fats
Trans fatty acids are harmful fat sources manufacturers add to extend the shelf life of foods. These fat sources are produced when hydrogen is added to vegetable oils. Examples of foods that contain trans fats include fried foods and processed foods such as baked and prepackaged goods. Trans fats are linked with lowering HDL cholesterol and increasing LDL cholesterol. Manufacturers must list trans fats on nutrition labels -- avoid eating foods that contain them in any amount.
