Cortisol reactivity, an index of hypothalamic-pituitary-adrenal function, may be another mechanism by which psychosocial stress is associated with future hypertension.  In a prospective sub-study of the Whitehall II cohort, with 3 years follow-up of an occupational cohort in previously healthy patients, investigators reported 15.9% of the patient sample developed hypertension in response to laboratory-induced mental stressors and found an association between cortisol stress reactivity and incident hypertension. 
To measure your blood pressure, a specialist places an inflatable cuff around your arm and measures your blood pressure using a pressure-measuring gauge. A blood pressure reading, as shown in the blood pressure monitor in the image, measures the pressure in your arteries when your heart beats (systolic pressure) in the first number, and the pressure in your arteries between heartbeats (diastolic pressure) in the second number.
According to guidelines from the American Heart Association (AHA) and the American College of Cardiology (ACC), a reading below 120/80 mm Hg is classified as normal blood pressure. Those with a blood pressure reading anywhere from 120/80 up to 129/80 are classified within a category called elevated blood pressure. Hypertension is defined as a reading of 130/80 or higher.
Furthermore, of those with high blood pressure (BP), 78% were aware they were hypertensive, 68% were being treated with antihypertensive agents, and only 64% of treated individuals had controlled hypertension.  In addition, previous data from NHANES estimated that 52.6% (NHANES 2009-2010) to 55.8% (NHANES 1999-2000) of adults aged 20 years and older have prehypertension, defined as an untreated SBP of 120-139 mm Hg or untreated DBP of 80-89 mmHg.  (See Epidemiology.)