What is metabolic syndrome, and how is it defined?
The sources list five measures behind metabolic syndrome, and they word the cutoffs differently in places. This page sets them side by side.
Arun Verma, co-founder of Triangle · 2026-10-17
This is not clinical evidence and not medical advice. It does not replace your care team. Discuss anything here with your clinician before you act on it.
What is metabolic syndrome?
NHLBI describes metabolic syndrome as a group of conditions that together raise your risk of coronary heart disease, diabetes, stroke, and other serious health problems. MedlinePlus says you can have just one risk factor, but people often have several together, and that having at least three is called metabolic syndrome. The five measures the sources list are waist size, triglycerides, HDL cholesterol, blood pressure and fasting blood sugar. The cutoffs are in the next answer.
What are the five measures, and what are the cutoffs?
Waist size, triglycerides, HDL cholesterol, blood pressure and fasting blood sugar. NHLBI says a large waistline is also called abdominal obesity or "having an apple shape." MedlinePlus lists the cutoffs as a waist of 35 inches or more for women and 40 inches or more for men, triglycerides of 150 mg/dL or higher, HDL cholesterol below 50 mg/dL for women and below 40 mg/dL for men, a blood pressure reading of 130/85 mmHg or higher, and a fasting blood sugar of 100 mg/dL or higher. NHLBI says your provider measures your waist during the physical exam, checks your blood pressure, and does blood tests to measure your blood sugar, cholesterol and triglyceride levels. It gives its blood sugar ranges for readings after 8 to 12 hours of fasting (not eating). The American Heart Association's list also counts the triglyceride, HDL, blood pressure and fasting glucose measures when someone is taking medicine for them. For a child, NHLBI says the child's provider will determine the measures and cutoff numbers.
Where do the sources word the cutoffs differently?
The waist cutoff is one place. NHLBI says you may have abdominal obesity, one of the conditions, if your waist measures more than 40 inches for men and 35 inches for women. MedlinePlus says 40 inches or more for men and 35 inches or more for women, so exactly 40 or 35 inches falls on different sides depending on the source. Triglycerides split the same way at exactly 150 mg/dL. NHLBI also says your provider may use different waist measurement values for diagnosis, depending on your race and ethnicity. If a value sits right on a line, you could ask which cutoff your clinician's own criteria use.
What are triglycerides and HDL, and what are the units on a report?
MedlinePlus says triglycerides are a type of fat found in the blood, and that HDL is sometimes called the "good" cholesterol because it helps remove cholesterol from your arteries. NHLBI says mmHg, millimeters of mercury, is the unit used to measure blood pressure, and mg/dL, milligrams per deciliter, is the unit used to measure blood sugar, triglycerides and cholesterol. You could ask which unit each result on your report is in.
What else might my records call it?
NHLBI says it's also called insulin resistance syndrome. MedlinePlus lists that name and metabolic syndrome X. You could ask which name appears in the chart and which of the five measures were counted toward it.
Does metabolic syndrome cause symptoms?
MedlinePlus says most of the metabolic risk factors have no obvious signs or symptoms, except for a large waistline. NHLBI says high blood pressure, high blood triglycerides, and low HDL cholesterol usually do not cause any symptoms. It also says your provider may tell you that you have metabolic syndrome based on tests, such as blood pressure readings and blood tests, that you would get as part of a routine medical visit.
Who decides whether someone has it, and what do they review?
The American Heart Association says metabolic syndrome is diagnosed by a healthcare professional, when you have three or more of the five conditions. NHLBI says your provider will diagnose metabolic syndrome based on your medical and family history, a physical exam, and diagnostic tests, and will ask whether you or others in your family have any symptoms or risk factors. A fair question is which of the five were counted for you, and from which dates.
What do the sources say about the count of three and the word "consistently"?
MedlinePlus says you must have at least three of the risk factors to be diagnosed with metabolic syndrome. NHLBI words the blood pressure and triglyceride criteria with the word consistently, as in blood pressure that is consistently 130/85 mmHg or higher. You could ask whether a given number was a one-off or has held steady across visits.
How common is metabolic syndrome?
About 1 in 3 US adults, according to NHLBI (page updated May 2022).
What could I ask my clinician about my own numbers?
You could ask which of the five your clinician counts for you, which cutoff and unit they used for each, and whether the blood sugar was a fasting sample. You could ask whether the waist measurement, blood pressure readings and lab results are all being read together. Another fair question is whether any value sits right on a line, given the wording differences above, and what else is reviewed alongside those five numbers.
Sources
- NHLBI: Metabolic Syndrome — What Is Metabolic Syndrome? (last updated May 18, 2022): NHLBI says metabolic syndrome is a group of conditions that together raise your risk of coronary heart disease, diabetes, stroke, and other serious health problems.
- NHLBI: Metabolic Syndrome — What Is Metabolic Syndrome? (last updated May 18, 2022): NHLBI says you may have metabolic syndrome if you have three or more of five conditions: a large waistline, blood pressure, blood sugar, triglycerides, and HDL cholesterol (each listed in its high or low form).
- MedlinePlus: Metabolic Syndrome: MedlinePlus says you can have just one of the risk factors, but people often have several together, and that having at least three is called metabolic syndrome.
- MedlinePlus: Metabolic Syndrome: MedlinePlus lists a waist measurement of 35 inches or more for women and 40 inches or more for men as the large-waistline cutoff.
- MedlinePlus: Metabolic Syndrome: MedlinePlus lists a triglyceride level of 150 mg/dL or higher as the high-triglyceride cutoff.
- MedlinePlus: Metabolic Syndrome: MedlinePlus lists an HDL cholesterol level of less than 50 mg/dL for women and less than 40 mg/dL for men as the low-HDL cutoff.
- MedlinePlus: Metabolic Syndrome: MedlinePlus lists a blood pressure reading of 130/85 mmHg or higher as the blood pressure cutoff.
- MedlinePlus: Metabolic Syndrome: MedlinePlus lists a fasting blood sugar of 100 mg/dL or higher as the blood sugar cutoff.
- NHLBI: Metabolic Syndrome — Diagnosis (last updated May 18, 2022): NHLBI says that for diagnosis your provider measures your waist during the physical exam, checks your blood pressure, and does blood tests to measure your blood sugar, cholesterol, and triglyceride levels.
- NHLBI: Metabolic Syndrome — Diagnosis (last updated May 18, 2022): NHLBI gives its blood sugar ranges for readings after 8 to 12 hours of fasting (not eating).
- NHLBI: Metabolic Syndrome — Diagnosis (last updated May 18, 2022): NHLBI says that for a child, the child's provider will determine the measures and cutoff numbers.
- NHLBI: Metabolic Syndrome — Diagnosis (last updated May 18, 2022): NHLBI says you may have abdominal obesity, one of the conditions of metabolic syndrome, if your waist measures more than 40 inches for men and 35 inches for women.
- NHLBI: Metabolic Syndrome — Diagnosis (last updated May 18, 2022): NHLBI says triglyceride levels that are consistently more than 150 mg/dL are one of the conditions of metabolic syndrome.
- NHLBI: Metabolic Syndrome — Diagnosis (last updated May 18, 2022): NHLBI says blood pressure that is consistently 130/85 mmHg or higher is one of the conditions of metabolic syndrome.
- NHLBI: Metabolic Syndrome — Diagnosis (last updated May 18, 2022): NHLBI says your provider may use different waist measurement values for diagnosis, depending on your race and ethnicity.
- American Heart Association: Symptoms and Diagnosis of Metabolic Syndrome (last reviewed Oct 17, 2023): AHA says metabolic syndrome is a cluster of conditions that is diagnosed by a healthcare professional, when you have three or more of five listed conditions.
- MedlinePlus: Metabolic Syndrome: MedlinePlus says your health care provider will diagnose metabolic syndrome based on the results of a physical exam and blood tests, and that you must have at least three of the risk factors.
- American Heart Association: Symptoms and Diagnosis of Metabolic Syndrome (last reviewed Oct 17, 2023): The American Heart Association says its list also counts the triglyceride, HDL, blood pressure and fasting glucose measures when someone is taking medicine for them.
- MedlinePlus: Metabolic Syndrome: MedlinePlus lists insulin resistance syndrome and metabolic syndrome X as other names for metabolic syndrome.
- MedlinePlus: Metabolic Syndrome: MedlinePlus says triglycerides are a type of fat found in the blood.
- MedlinePlus: Metabolic Syndrome: MedlinePlus says HDL is sometimes called the "good" cholesterol because it helps remove cholesterol from your arteries.
- NHLBI: Metabolic Syndrome — Diagnosis (last updated May 18, 2022): NHLBI says mmHg (millimeters of mercury) is the unit used to measure blood pressure, and mg/dL (milligrams per deciliter) is the unit used to measure blood sugar, triglycerides, and cholesterol.
- NHLBI: Metabolic Syndrome — What Is Metabolic Syndrome? (last updated May 18, 2022): NHLBI says metabolic syndrome is also called insulin resistance syndrome.
- MedlinePlus: Metabolic Syndrome: MedlinePlus says most of the metabolic risk factors have no obvious signs or symptoms, except a large waistline.
- NHLBI: Metabolic Syndrome — Symptoms (last updated May 18, 2022): NHLBI says high blood pressure, high blood triglycerides, and low HDL cholesterol usually do not cause any symptoms.
- NHLBI: Metabolic Syndrome — Symptoms (last updated May 18, 2022): NHLBI says your provider may tell you that you have metabolic syndrome based on tests, such as blood pressure readings and blood tests, that you would get as part of a routine medical visit.
- NHLBI: Metabolic Syndrome — Diagnosis (last updated May 18, 2022): NHLBI says your provider will diagnose metabolic syndrome based on your medical and family history, a physical exam, and diagnostic tests.
- NHLBI: Metabolic Syndrome — Diagnosis (last updated May 18, 2022): NHLBI says your provider will ask whether you or others in your family have any symptoms or risk factors.
- NHLBI: Metabolic Syndrome — What Is Metabolic Syndrome? (last updated May 18, 2022): NHLBI says a large waistline is also called abdominal obesity or "having an apple shape."
- NHLBI: Metabolic Syndrome — What Is Metabolic Syndrome? (last updated May 18, 2022): NHLBI says metabolic syndrome is common in the United States, with about 1 in 3 adults having it.
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