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Hypertension Introduction The word “hypertension” as with many terms of modern medicine is derived from two Greek words, “Hyper” meaning excessive or above, and “Tonos” meaning tension, refers specifically to excessive pressure in the blood vessels. The exact definition of an abnormal blood pressure is controversial and phrases which provide no information are routinely found in the literature, an example would be: that level of blood pressure above which investigation and treatment do more good than harm. There are clearer definitions from the World Health Organisation and the Joint National Committee on the Prevention, Detection, Evaluation, and Treatment of High Blood Pressure (JNC-VI) in their sixth report provide a detailed definition of the stages of hypertension. “Resting long-term blood pressure of over 140/90mmHg if aged less than 50 years, or of over 160/95 if over 50” World Health Organisation Classification Systolic (mmHg) Diastolic (mmHg) Optimal <120 and/or <80 Normal <130 and/or <85 High Normal 130-139 and/or 85-89 Stage 1 (mild) HT 140-159 and/or 90-99 Stage 2 (moderate) HT 160-179 and/or 100-109 Stage 3 (severe) HT >180 and/or >110 JNC-VI (1997) Classification of adult blood pressure Hypertension can be divided into two categories, primary (essential) or secondary hypertension. The vast majority of hypertensive patients (90%) have primary hypertension which is idiopathic in that there is no obvious cause. Primary hypertension has a complex aetiology but these can be broadly divided into two components, a genetic component and an environmental component. Genetic research has shown that the inheritance of a number of abnormal genes predisposes individuals to hypertension; this research is ongoing and these genes are polymorphic in nature, and thus far the exact genetic sequence causing hypertension is elusive. Environmental factors also play an important role in the development of hypertension. These include individual weight, dietary intake of salt, fats, alcohol and frequency and intensity of exercise. Modifying these factors is recommended as an initial and adjunct to treating hypertension by all medical institutions. The remaining 10% of hypertensive patients have hypertension secondary to an identifiable disease process. These can vary widely, from renovascular diseases, which may lead to excessive activation of the rennin-angiotensin-aldosterone system impairing volume regulation in the kidneys, to endocrine disturbances, where the adrenal glands excessively secrete aldosterone, catecholamines, and cortisol. In this essay I intend to examine the benefits for hypertensive patients of modifying environmental factors, particularly the benefits of exercise for treating or preventing hypertension. Lifestyle Modification There are several well documented lifestyle changes that are considered to help prevent, reduce or eliminate established hypertension, or reduce the number and strength of medications needed to treat hypertension. These include reducing alcohol consumption, mineral intake, and obesity; smoking cessation and increasing exercise. Alcohol Many epidemiological studies and investigations have established a close association between alcohol consumption and hypertension (Klatsky et al, 1996)1. Some studies have suggested a linear relationship between increasing alcohol consumption and hypertension once a consumption threshold of three drinks per day (30g of ethanol) has been reached (Moreira et al, 1998)2.
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