However, at 12 months more than half of patients still had uncontrolled hypertension (systolic blood pressure > 140 mmHg and/or diastolic blood pressure > 90 mmHg).

During the dark-chocolate phase, their blood pressure dropped: the systolic (top) number by 5 points, the diastolic (bottom) by 2 points.

A normal blood pressure reading requires a systolic value of 91-119 and a diastolic value of 61-79.