Obesity and Cardiovascular Disease
Obesity and Cardiovascular Disease - OBESITY, a condition in which excess body weight is 20 percent or more above healthy weight as a result of excessive body fat, emerged in the 1990s as an independent risk factor for CARDIOVASCULAR DISEASE (CVD). This means that without any other additional RISK FACTORS FOR CARDIOVASCULAR DISEASE, obesity makes CVD more likely. However, the relationship between obesity and CVD is complex. Other health conditions associated with obesity also increase the risk for numerous types of cardiovascular disease. Prominent among them are HYPERTENSION (high BLOOD PRESSURE), INSULIN RESISTANCE, HYPERLIPIDEMIA, and DIABETES. Some health experts believe obesity is as significant a risk factor for cardiovascular disease as cigarette smoking.
Doctors define obesity as a BODY MASS INDEX (BMI) of 30 kilograms per meter squared (kg/m2) or higher. This corresponds to about 20 percent above healthy weight. BMI correlates body weight with health risk. At a BMI of 30, a person is likely to have at least one health condition associated with obesity. As BMI rises, so do the associated health conditions and the risk for cardiovascular disease. When BMI reaches 40, it is unusual for there not to be some form of cardiovascular disease present.
| BMI AND CARDIOVASCULAR DISEASE RISK | ||
|---|---|---|
| BMI (kg/m2) | Cardiovascular Risk | Conditions |
| 18.5-24.9: healthy | not affected | none |
| 25-29.9: overweight | increased | HYPERLIPIDEMIA; HYPERTENSION manageable through lifestyle |
| 30-34.9: OBESITY | high | hyperlipidemia; hypertension; ATHEROSCLEROSIS manageable through lifestyle and medication |
| 35-39.9: severe obesity | very high | hyperlipidemia; hypertension; atherosclerosis; mild to moderate CORONARY ARTERY DISEASE (CAD); DIABETES (type 2); OBSTRUCTIVE sleep apnea management requires multiple medications |
| 40+: morbid obesity | extremely high | hyperlipidemia; hypertension; atherosclerosis; moderate to severe CAD; symptomatic HEART FAILURE; diabetes; obstructive sleep apnea multiple medications necessary though may not entirely manage cardiovascular conditions |
Obesity affects cardiovascular function mechanically and metabolically. Excessive body fat pressures the BLOOD vessels, causing the heart to work harder to pump blood through them. As well, there is more surface area that the cardiovascular system must perfuse with blood. Excessive body fat may compress the neck, causing OBSTRUCTIVE SLEEP APNEA (episodes during sleep in which the person stops BREATHING). Obstructive sleep apnea prevents adequate air flow to the LUNGS, reducing oxygenation of the blood and causing ischemic episodes in which the heart does not receive enough oxygen, which results in ARRHYTHMIA. Excessive body fat may also compress the heart itself, further increasing the forces against which it must work to pump blood. All of these factors conspire to raise blood pressure and increase HEART RATE in an attempt to help the heart, which, if allowed to progress unchecked, are likely to result in HEART FAILURE.
Metabolically, obesity triggers INSULIN dysfunction. Because insulin plays a key role in cholesterol synthesis in the LIVER, hyperlipidemia is likely. Hyperlipidemia contributes to CORONARY ARTERY DISEASE (CAD) and PERIPHERAL VASCULAR DISEASE (PVD). A more significant health concern is the evolution from insulin resistance to diabetes. Diabetes increases cardiovascular disease risk substantially, as it is itself an independent risk factor for, as well as a leading cause of, cardiovascular disease.
When obesity declines even modestly, cardiovascular risk drops and cardiovascular health improves. As little as a 10-pound weight loss can drop systolic blood pressure by 10 millimeters of mercury (mm Hg). With sustained weight loss, many cardiovascular symptoms retreat and risk continues to fall.
See also BODY FAT PERCENTAGE; CARDIOVASCULAR DISEASE PREVENTION; EATING HABITS; DIET AND HEALTH; EXERCISE AND HEALTH; LIFESTYLE AND CARDIOVASCULAR HEALTH; OBESITY AND DIABETES; WEIGHT LOSS AND WEIGHT MANAGEMENT.
