Keeping the right amount of cholesterol in your blood is essential. Without cholesterol, basic bodily functions would shut down because the natural substance is an important component of hormones and cells. However, too much in your blood can be dangerous to your heart, so it's important to achieve a balance.

Researchers have found that this may be as simple as throwing away the cigarettes and making dietary and other lifestyle changes. For this month, National Cholesterol Education Month, health experts are especially urging Americans to exercise.

Good vs. bad cholesterol

The health community refers to bad cholesterol as low-density lipoprotein (LDL), and the technical name for good cholesterol is high-density lipoprotein (HDL). High levels of LDL cause arteries to become clogged and increase a person's risk for developing heart disease. Conversely, high levels of HDL help to remove LDL deposits from the arteries and transport circulating cholesterol to the liver, which removes the cholesterol from the body.

Thus, HDL clearly is helpful in lowering a person's risk for heart disease. In fact, researchers have shown that you can increase heart-disease risk just by not having enough HDL. For maximum health benefits, increasing your HDL and decreasing your LDL is ideal. Doctors recommend that total cholesterol levels remain below 200 mg/dl; HDL at least 35 mg/dl; and LDL below 100 mg/dl.

Exercise is key, even moderate activities such as walking

Numerous studies have clearly demonstrated the importance of exercise for maintaining favorable levels of cholesterol. In one study, researchers compared master athletes to sedentary men and found that, regardless of body weight, the athletes had significantly higher HDL levels. Naturally, this difference was even greater when comparing the athletes to obese men.

Another study observed more than 100 men and women who exercised more than 200 minutes a week for 10 months. While their HDL levels increased by an average of 10 percent, their LDL levels also decreased by about 10 percent.

Most recently, researchers at Grand Valley State University in Allendale, Michigan found that moderate-intensity workouts were just as effective in increasing HDL levels as high-intensity workouts. In the study, published in the June issue of Archives of Physical Medicine and Rehabilitation, researchers put 25 women on a 12-week exercise regimen of walking two miles, three times a week. One-half of the women worked out at a moderate-intensity pace; another group walked with higher intensity. After the 12 weeks, women in both groups significantly increased their HDL levels, compared to their levels at the start of the study.

Trying it at home

As the results of these and numerous other studies show, participating in some type of aerobic exercise is important. Whether walking, running or biking, try to exercise a minimum of three days a week for at least 30 minutes. (Exercising more frequently and for longer periods of time is certainly better.) Remember, you can also factor in your daily physical activity, which counts too -- walking to work instead of driving, for example, will help to keep your cholesterol levels in balance.

In the Grand Valley study, the women in the moderate-intensity group were walking at an intensity the fitness world refers to as 60 percent of age-predicted maximal heart rate, which is the number of times your heart beats in one minute. The women who walked at high intensity were walking at 80 percent. To calculate the rate at which your heart should be beating at these intensity levels, use the following steps: Calculate the difference between your age and 220. Then, multiply that difference by 0.60 or 0.80, depending upon your goals. This is your maximal heart rate for an aerobic intensity of 60 percent or 80 percent, respectively.

Don't forget the fat

As much as exercise appears to affect LDL and HDL levels, a low-fat diet also seems to have very beneficial effects. In one study, sedentary people either began exercising, adopted a low-fat diet, or both. By the end of the study, LDL levels dropped in both groups but decreased even more in people who both exercised and ate a low-fat diet.

Making exercise and a low-fat diet a permanent part of your life will benefit your health in many ways. A healthy lifestyle will help you maintain an ideal body weight -- which will not only positively affect your HDL cholesterol, but also reduce your risk of developing other chronic diseases such as arthritis, obesity and diabetes.

by Miriam Nelson, PhD
Created October, 2000