If your HDL Cholesterol Level is Less than 40 mg/dL, then this is A major risk factor for heart disease Category.If your HDL Cholesterol Level is 40-59 mg/dL, then this is a The higher, the better Category.ere are the ranges for HDL cholesterol levels. Do you know how your HDL cholesterol level compares? If your HDL Cholesterol Level is Less than 40 mg/dL, then this is A major risk factor for heart disease Category. If your HDL Cholesterol Level is 40-59 mg/dL, then this is a The higher, the better Category.