Dear Doctors Column July 20, 2009
Small Changes in Weight and Exercise Can Reduce Heart-Failure Risk
Question:
How much do I need to exercise to keep my heart healthy? How much does my weight matter?
Answer:
Exercising just a few times a month or shedding a few pounds can make a difference in your heart's health. If you increase your activity level and lose weight, you can make a dramatic difference in your risk of heart failure, according to a new analysis of information from the long-term Physicians' Health Study.
Heart failure affects 5 million Americans and contributes to 300,000 deaths a year. It is a condition in which your heart cannot supply enough blood flow to meet your body's needs.
In the Physicians' Health Study, researchers collected data during a 20-year period on more than 21,000 men with an average age of 54 at the study's start. Participants were male physicians who completed questionnaires about demographics, lifestyle, and medical history.
Doctors have known for a long time that obesity and heart failure are related and that exercise benefits the heart, but researchers continue to clarify relationships among these factors. This new analysis shows that weight and exercise each affect the risk of heart failure independently, and when people lose weight and exercise regularly, they reap even more benefit. The analysis also produced the first clear evidence that carrying any extra weight increases risk of heart failure.
Investigators defined participants as obese if they had a body mass index (BMI) greater than 30, as overweight if they had a BMI of 25 to 29.9, and as lean if they had a BMI less than 25. BMI is calculated from your weight and height. You can calculate your BMI here.
Researchers found that a higher BMI increased the risk of heart failure in men, regardless of their exercise habits. Each extra 7 pounds-about a one point increase in BMI-carried an 11% greater risk of heart failure. Overweight participants were 49% more likely to suffer heart failure, and obese men had a 180% greater risk.
Vigorous exercise, ie, exercise hard enough to break a sweat, reduced risk of heart failure by 18% in all men, whether lean, overweight, or obese. Participants exercised as few as one to three times a month and up to a maximum of five to seven times a week. Those who exercised more frequently received greater benefits - up to a 36% reduction in heart failure risk.
Compared to lean, physically active men, risk of heart failure increased:
- 19% for lean, inactive men
- 49% for overweight, active men
- 78% for overweight, inactive men
- 168% in obese, active men
- 293% in obese, inactive men
The American Heart Association (AHA) points out that BMI is only one factor that health care providers should measure. An assessment of heart health also should include measuring lean muscle mass and evaluating fat distribution -- carrying a lot of fat around your middle, for example, raises your risk for heart problems more than fat around your hips. Many experts believe measuring waist circumference in addition to BMI gives the best picture of weight-related heart disease risk.