Which of the following is a component of metabolic syndrome?

A large waistline is indeed a recognized component of metabolic syndrome. This syndrome encompasses a cluster of conditions that occur together, increasing the risk of heart disease, stroke, and type 2 diabetes. One of the defining features is visceral obesity or abdominal fat, often measured by waist circumference. A larger waistline indicates greater amounts of visceral fat, which is associated with metabolic disturbances such as insulin resistance and increased levels of triglycerides.

The other options do not align with the criteria for metabolic syndrome. Low blood pressure, low cholesterol levels, and increased physical fitness do not contribute to the syndrome's risk factors. Rather, individuals with metabolic syndrome typically exhibit conditions such as high blood pressure, high triglycerides, and low levels of HDL (the "good" cholesterol).