Healthier Life: Exercise to control cholesterol

KIRTLAND AIR FORCE BASE, N.M. -- September is National Cholesterol Education Awareness Month, so it’s a good time to revisit the health impact of heart disease and high cholesterol. 

According to the Centers for Disease Control and Prevention, heart disease is still the leading cause of death for men and women in the U.S. About 630,000 Americans die from heart disease each year. 

Science has identified several risk factors for heart disease. Some of these can’t be changed, such as age, gender and family history. 

Many can be changed, however. These include physical inactivity, unhealthy diet, smoking status, obesity and excessive alcohol use. 

One of the strongest modifiable risk factors for heart disease is high cholesterol. Someone with high cholesterol has about twice the risk of heart disease as people with normal cholesterol, so reducing high cholesterol is a critical component for reducing heart-disease risk.

Cholesterol is a waxy, fat-like substance that can be found in all parts of the body. 

Your body uses cholesterol for making various hormones, vitamin D and bile acids. Cholesterol also helps to protect nerve fibers. 

Only a small amount of cholesterol is essential, and excess cholesterol may be deposited on the inside of arteries if blood levels are too high. A cholesterol test will usually include total cholesterol (TC), high-density lipoprotein (HDL), low-density lipoprotein (LDL) and triglycerides (a type of blood fat).

Desirable levels would be a TC of less than 200, an HDL of 60 or higher, LDL less than 100 and triglycerides less than 150. Total cholesterol represents the total amount of cholesterol in your blood, which includes HDL cholesterol, LDL cholesterol, intermediate density lipoproteins (IDL), very low-density lipoproteins (VLDL) and lipoprotein (a). 

HDL cholesterol, the “good” cholesterol, reduces heart-disease risk. LDL cholesterol, the “bad” cholesterol, increases the risk. 

High triglycerides also increase heart-disease risk, particularly when associated with low HDL and/or high LDL cholesterol. 

There are two subtypes of LDL cholesterol, which are differentiated by particle size and density. Small dense LDL, the “really bad” cholesterol, is directly related to increased occurrence of heart disease. 

The two LDL subtypes are not separated in typical cholesterol tests, though high triglycerides (more than 200) are associated with increased numbers of “really bad” LDL. Some research suggests the total cholesterol minus HDL cholesterol, called “non-HDL-C,” may be a more important predictor of heart-disease risk than LDL cholesterol alone.

We commonly think of heart disease as a “modern” disease, but studies of ancient people show heart disease goes back thousands of years. Mummies from Egypt, Peru, North America and the Aleutian Islands document heart disease in all these populations. 

The oldest known occurrence of heart disease is a 5,000-year-old mummy from the Italian Alps. Though this research indicates heart disease has been with humans for a long time, we also know lifestyle can accelerate the progression of heart disease. 

One well-documented risk factor is physical inactivity. Physical inactivity is strongly correlated with high cholesterol and heart-disease mortality, and high levels of physical activity appear to have a protective effect for both. 

This effect applies to aerobic training and weight training. For aerobic training, most studies have shown that in the absence of weight loss, cardiovascular exercise does not significantly alter LDL cholesterol levels. 

Cardiovascular training does alter LDL particle size, so the “really bad” LDL becomes less bad. Cardio training also lowers blood triglyceride levels by an average of 11 percent. 

High volumes of exercise will produce greater improvements in triglycerides and LDL particle size than lower amounts. Weight loss from exercise will reduce LDL levels by nearly one point for every 2 pounds of weight loss, so a 10-pound weight loss would lower LDL by about 4 points. 

In addition, aerobic training results in significant increases in HDL cholesterol, independent of weight changes. 

Resistance training also appears to improve cholesterol. Resistance training significantly lowers levels of TC, LDL, non-HDL-C and triglycerides. 

It’s unknown whether weight training changes LDL particle size. Weight training does not appear to increase HDL cholesterol. 

What would an exercise program for lowering cholesterol look like? For aerobic training, five to seven days per week, 40-60 minutes per day, with an intensity where you could talk to someone with difficulty would be recommended. 

The mode of training — walk/run/cycle/elliptical — doesn’t matter. 

For resistance training, work each major muscle group — back, chest, legs — twice per week, with at least one day off between sessions of the same muscle group. For example, if you worked your back on Monday, you would wait until at least Wednesday to work it again. 

Total number of sets to fatigue should be three to four, and about two minutes of rest between sets. Machine weights and free weights are both effective. 

I recommend beginners start with strength machines, because the injury risk is far less than with free weights. Because cardio training and weight training produce different benefits, it’s best to include both to maximize the cholesterol-lowering effects of exercise. 

For more information about lowering cholesterol, contact me at 846-1186 or guy.leahy.2@us.af.mil.