Metabolic syndrome is a cluster of conditions that occur together, increasing your risk of heart disease, stroke and diabetes.

Having just one of these conditions — increased blood pressure, elevated insulin levels, excess body fat around the waist or abnormal cholesterol levels — isn't diagnosed as metabolic syndrome, but it does contribute to your risk of serious disease. If more than one of these conditions occur in combination, your risk is even greater.

If you have metabolic syndrome or any of the components of metabolic syndrome, you have the opportunity to make aggressive lifestyle changes. Making these changes can delay or derail the development of serious diseases that may result from metabolic syndrome.

Having metabolic syndrome means you have several disorders related to your metabolism at the same time, including:

• Obesity, particularly around your waist (having an "apple shape")
• Elevated blood pressure
• An elevated level of the blood fat called triglycerides and a low level of high-density lipoprotein (HDL) cholesterol — the "good" cholesterol
• Resistance to insulin, a hormone that helps to regulate the amount of sugar in your body

Having one component of metabolic syndrome means you're more likely to have others. And the more components you have, the greater are the risks to your health.

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Normal metabolism

Research into the complex underlying process linking the group of conditions involved in metabolic syndrome is ongoing. As the name suggests, metabolic syndrome is tied to your body's metabolism, possibly to a condition called insulin resistance. Insulin is a hormone made by your pancreas that helps control the amount of sugar in your bloodstream.

Normally, your digestive system breaks down some of the foods you eat into sugar (glucose). Your blood carries the glucose to your body's tissues, where the cells use it as fuel. Glucose enters your cells with the help of insulin. In people with insulin resistance, cells don't respond normally to insulin, and glucose can't enter the cells as easily. Your body reacts by churning out more and more insulin to help glucose get into your cells. The result is higher than normal levels of both insulin and glucose in your blood.

Although perhaps not high enough to qualify as diabetes, an elevated glucose level still interferes with your body processes. Increased insulin raises your triglyceride level and other blood fat levels. It also interferes with how your kidneys work, leading to higher blood pressure. These combined effects of insulin resistance put you at risk of heart disease, stroke, diabetes and other conditions.

Combination of factors
Researchers are still learning what causes insulin resistance. It probably involves a variety of genetic and environmental factors. They think some people are genetically prone to insulin resistance, inheriting the tendency from their parents. But being overweight and inactive are major contributors.

Disagreement among experts
Not all experts agree on the definition of metabolic syndrome or whether it even exists as a distinct medical condition. Doctors have talked about this constellation of risk factors for years and have called it many names, including syndrome X and insulin resistance syndrome. Whatever it's called, and however it's precisely defined, this collection of risk factors is apparently becoming more prevalent.

The following factors increase your chances of having metabolic syndrome:

• Age. The prevalence of metabolic syndrome increases with age, affecting less than 10 percent of people in their 20s and 40 percent of people in their 60s. However, some research shows that about one in eight schoolchildren has three or more components of metabolic syndrome. And, other research has identified an association between childhood metabolic syndrome and adult cardiovascular disease decades later.
• Race. Hispanics and Asians seem to be at greater risk of metabolic syndrome than other races are.
• Obesity. A body mass index (BMI) — a measure of your percentage of body fat based on height and weight — greater than 25 increases your risk of metabolic syndrome. So does abdominal obesity — having an apple shape rather than a pear shape.
• History of diabetes. You're more likely to have metabolic syndrome if you have a family history of type 2 diabetes or a history of diabetes during pregnancy (gestational diabetes).
• Other diseases. A diagnosis of high blood pressure, cardiovascular disease or polycystic ovary syndrome — a similar type of metabolic problem that affects a woman's hormones and reproductive system — also increases your risk of metabolic syndrome.

If you know you have at least one aspect of metabolic syndrome — such as high blood pressure, high cholesterol or an apple-shaped body — you may have the others and not know it. It's worth checking with your doctor. Ask whether you need testing for other components of the syndrome and what you can do to avoid serious diseases.

Although your doctor is not typically looking for "metabolic syndrome," the label may apply if you have three or more of the traits associated with this condition.

Several organizations have criteria for diagnosing metabolic syndrome. These guidelines were created by the National Cholesterol Education Program (NCEP) with modifications by the American Heart Association. According to these guidelines, you have metabolic syndrome if you have three or more of these traits:

• Elevated waist circumference, greater than 35 inches for women and 40 inches for men. Certain genetic risk factors, such as having a family history of diabetes or being of Asian descent — which increases your risk of insulin resistance — lower the waist circumference limit. If you have one of these genetic risk factors, waist circumference limits are 31 to 35 inches for women and 37 to 39 inches for men.
• Elevated level of triglycerides of 150 milligrams per deciliter (mg/dL) or higher, or you're receiving treatment for high triglycerides.
• Reduced HDL (less than 40 mg/dL in men or less than 50 mg/dL in women) or you're receiving treatment for low HDL.
• Elevated blood pressure of 130 millimeters of mercury (mm Hg) systolic (the top number) or higher or 85 mm Hg diastolic (the bottom number) or higher, or you're receiving treatment for high blood pressure.
• Elevated fasting blood sugar (blood glucose) of 100 mg/dL or higher, or you're receiving treatment for high blood sugar.

Tackling one of the risk factors of metabolic syndrome is tough — taking on all of them might seem overwhelming. But aggressive lifestyle changes and, in some cases, medication can improve all of the metabolic syndrome components. Getting more physical activity, losing weight and quitting smoking help reduce blood pressure and improve cholesterol and blood sugar levels. These changes are key to reducing your risk.

• Exercise. Doctors recommend getting 30 to 60 minutes of moderate intensity exercise, such as brisk walking, every day.
• Lose weight. Losing as little as 5 percent to 10 percent of your body weight can reduce insulin levels and blood pressure and decrease your risk of diabetes.
• Eat healthy. The Dietary Approaches to Stop Hypertension (DASH) diet and the Mediterranean Diet, like many healthy-eating plans, limit unhealthy fats and emphasize fruits, vegetables, fish and whole grains. Both of these dietary approaches have been found to offer important health benefits - in addition to weight loss - for people who have components of metabolic syndrome.  Ask your doctor for guidance before starting a new eating plan.
• Stop smoking. Smoking cigarettes increases insulin resistance and worsens the health consequences of metabolic syndrome. Talk to your doctor if you need help kicking the cigarette habit.

Work with your doctor to monitor your weight and your blood glucose, cholesterol and blood pressure levels to ensure that lifestyle modifications are working. If you're not able to achieve your goals with lifestyle changes, your doctor may also prescribe medications to lower blood pressure, control cholesterol or help you lose weight. Insulin sensitizers may be prescribed to help your body use insulin more effectively. Aspirin therapy may help reduce your risk of heart attack and stroke.

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Mayo Clinic Healthy Weight Pyramid

Whether you have one, two or none of the components of metabolic syndrome, the following lifestyle changes will reduce your risk of heart disease, diabetes and stroke:

• Commit to a healthy diet. Eat plenty of fruits and vegetables. Choose lean cuts of white meat or fish over red meat. Avoid processed or deep-fried foods. Eliminate table salt and experiment with other herbs and spices.
• Get moving. Get plenty of regular, moderately strenuous physical activity.
• Schedule regular checkups. Check your blood pressure, cholesterol and blood sugar levels on a regular basis. Make additional lifestyle modifications if the numbers are going the wrong way.

You can do something about your risk of metabolic syndrome and its complications — diabetes, stroke and heart disease. You can begin to curb your insulin resistance by making these lifestyle changes:

• Lose weight. Losing as little as 5 percent to 10 percent of your body weight can reduce insulin levels and blood pressure, and decrease your risk of diabetes.
• Exercise. Doctors recommend getting 30 to 60 minutes of moderate-intensity exercise, such as brisk walking, every day.
• Stop smoking. Smoking cigarettes increases insulin resistance and worsens the health consequences of metabolic syndrome. Talk to your doctor if you need help kicking the cigarette habit.
• Eat fiber-rich foods. Make sure you include whole grains, beans, fruits and vegetables in your grocery cart. These items are packed with dietary fiber, which can lower your insulin levels.