Medicine.  A higher tension than normal blood pressure, specifically systolic blood pressure above 140 mm Hg and diastolic blood pressure above 90 mm Hg (140/90 mm Hg). Prolonged (chronic) high blood pressure is likely to induce cardiovascular (heart and circulatory system) damage or other adverse consequences. Pre-hypertension is systolic blood pressure between 120 and 139 mm Hg and diastolic blood pressure between 80 and 89 mm Hg. Pre-hypertension is an intermediate case between normal and high blood pressure. Normal blood pressure for adults is generally in the range of 90/50 to 120/90 mm Hg. Hypotension is an abnormally low blood pressure, usually below 90/50 mm Hg. In severe or prolonged cases, it can be a serious medical condition. Additional Info: Your heart contracts and relaxes to pumps blood through your arteries to all parts of your body. Blood pressure is the force of the blood against the walls of the arteries. Systolic pressure is a measure of the blood pressure when the heart pumps. Diastolic pressure is a measure of the pressure between heart beats. Elevated blood pressure is quite in common. Between 1 in 3 and 1 in 4 people have hypertension. Incidence of hypertension is significantly higher in African-Americans than in other racial groups. The chances of developing hypertension are increased for individuals who: (1) are overweight; (2) have a family history of hypertension; (3) are men over 45 and women over 55; (4) have prehypertension; (5) consume too much salt; (6) consume too much alcohol; (7) do not exercise; (8) do not consume enough potassium; (9) take certain medications; (10) have chronic high levels of stress. Hypertension can also be caused by a variety of other medical conditions. These cases are also called secondary hypertension. In other cases, there is no known cause (idiopathic), and the condition is sometimes called essential hypertension. Adverse consequences of chronic hypertension may include: (1) Retinal vascular damage. Blood vessels in the eye may burst and bleed, sometimes resulting in blindness. (2) Cerebrovascular disease and stroke due to "hardening" or damage to the blood vessels in your brain. (3) Left ventricular hypertrophy (enlarged heart), possibly leading to heart failure. (4) Myocardial infarction (heart attack). (5) Aneurysm (a weakened area in a blood vessel). Rupture of an aneurysm can lead to a stroke or death. (6) Renovascular disease. Blood vessels in the kidney may narrow or block completely, ultimately leading to kidney failure. Uncomplicated hypertension generally has no symptoms, so it is usually diagnosed through regular medical check-ups. Elevated blood pressure over several successive visits yields a diagnosis of hypertension or prehypertension. Prehypertension should be taken seriously as it can often progress to hypertension if the risk factors are not controlled. To prevent or reduce (pre)hypertension, doctors generally recommend an improved diet, regular exercise, and, if applicable, losing weight or quitting smoking. Diets rich in fruits, vegetables, fat-free dairy foods, and low in fat and sodium tend to lower blood pressure. Limiting consumption of alcohol can also help lower blood pressure, however moderate alcohol use has certain cardiovascular (heart and circulatory system) benefits. When these lifestyle changes are not sufficient to control hypertension, prescription medication is usually required. There are many different classes of antihypertensive medications, each working by a different mechanism. For example, diuretics such as hydrochlorothiazide are a cheap and effective drug for many people. While diuretics can help lower blood pressure by removing salt and extra fluid from the body, the actual mechanism of how they reduce blood pressure is not fully understood. Other antihypertensives work by slowing the heartbeat down or relaxing and widening the blood vessels. Medications that work in this way include: beta blockers, alpha blockers, ACE inhibitors, ARBS, calcium channel blockers, alpha-beta blockers, nervous system inhibitors, and vasodilators. In some cases, combinations of two or more antihypertensives may be required to bring your blood pressure under control. MSDS Relevance: Exposure to some chemicals, such as nephrotoxins can cause or aggravate hypertension. Exposure to other chemicals may cause a victim to go into shock, a symptom of which is very low blood pressure. Consult the Health Hazards section of your MSDS and use engineering controls or personal protective equipment to reduce your exposure. See also: Diuretic, Nephrotoxin, Syncope