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Hypertension
Blood Pressure
High blood pressure (HBP) or hypertension means high pressure (tension) in the arteries. Arteries are vessels that carry blood from the pumping heart to all the tissues and organs of the body. High blood pressure does not mean excessive emotional tension, although emotional tension and stress can temporarily increase blood pressure. Normal blood pressure is below 120/80; blood pressure between 120/80 and 139/89 is called "pre-hypertension", and a blood pressure of 140/90 or above is considered high.
The top number, the systolic blood pressure, corresponds to the pressure in the arteries as the heart contracts and pumps blood forward into the arteries. The bottom number, the diastolic pressure, represents the pressure in the arteries as the heart relaxes after the contraction. The diastolic pressure reflects the lowest pressure to which the arteries are exposed.
An elevation of the systolic and/or diastolic blood pressure increases the risk of developing heart (cardiac) disease, kidney (renal) disease, hardening of the arteries (atherosclerosis or arteriosclerosis), eye damage, and stroke (brain damage). These complications of hypertension are often referred to as end-organ damage because damage to these organs is the end result of chronic (long duration) high blood pressure. For that reason, the diagnosis of high blood pressure is important so efforts can be made to normalize blood pressure and prevent complications.
It was previously thought that rises in diastolic blood pressure were a more important risk factor than systolic elevations, but it is now known that in people 50 years or older systolic hypertension represents a greater risk.
The American Heart Association estimates high blood pressure affects approximately one in three adults in the United States - 73 million people. High blood pressure is also estimated to affect about two million American teens and children, and the Journal of the American Medical Association reports that many are under-diagnosed. Hypertension is clearly a major public health problem.
Blood pressure lowering effects of niacin-bound chromium(III) (NBC) in sucrose-fed rats: renin-angiotensin system.
J Inorg Biochem. 2008 Jul;102(7):1541-8. Epub 2008 Feb 23.
Perricone NV, Bagchi D, Echard B, Preuss HG.
Michigan State University College of Human Medicine, East Lansing, MI 48824-136, USA.
Excessive intake of sugars significantly elevates systolic blood pressure (SBP) in susceptible rats. Although the exact pathological mechanisms behind sugar-induced hypertension are uncertain and may be multiple, disturbances in the renin-angiotensin system (RAS) manifested by elevated circulating levels of angiotensin-2 may be involved. We attempted to confirm that the RAS was significantly involved in sugar-induced BP elevations and examined whether the ability of niacin-bound chromium (NBC) to ameliorate sugar-induced SBP elevations was due, at least in part, through effects on the RAS. Initially, 40 mature Sprague-Dawley rats (SD), male and female, were involved in the study comparing two methods to estimate rat blood pressure indirectly.
Then 13 were selected to examine the effects of NBC on the RAS. All rats eventually ingested a diet heavy in sucrose (30%w/w). In addition to blood pressure readings, the following procedures were implemented: insulin and losartan challenges, evaluation of serum ACE activity, measurement of serum angiotensin-2 levels, blood chemistries, and LNAME challenge. While dietary sucrose raised SBP significantly in control, adding NBC to the treatment group lowered it back toward baseline.
The treatment group was more sensitive to exogenous insulin challenge and showed decreased activity of the RAS estimated by less lowering of SBP after losartan challenge, decreased serum ACE (angiotensin-converting enzyme) activity, and lower levels of circulating angiotensin-2. The former two parameters showed statistical significance; and the latter, a trend toward statistical significance. A separate group receiving captopril served as a positive control and showed decreased ACE activity and circulating levels of angiotensin-2 compared to the control group. Our data suggest that the RAS plays a significant role in sugar-induced hypertension and that NBC lowers SBP, at least in part, via actions on the RAS. Other findings suggest that the NO system is important in sucrose-induced BP elevations as well.
Coffee blunts mental stress-induced blood pressure increase in habitual but not in nonhabitual coffee drinkers.
Hypertension. 2005 Sep;46(3):521-6. Epub 2005 Aug 15.
Sudano I, Spieker L, Binggeli C, Ruschitzka F, Lüscher TF, Noll G, Corti R.
Cardiovascular Center, Cardiology, University Hospital Zurich, Zurich, Switzerland.
Coffee is widely consumed, especially during mental stress conditions. Cardiovascular impact of coffee remains debated because the underlying mechanisms of action are complex. We reported previously differential cardiovascular stimulation of coffee at rest depending on habitual consumption.
The present study was designed to evaluate the effects of coffee on cardiovascular response to mental stress. In 15 healthy volunteers (6 habitual, 9 nonhabitual coffee drinkers), we assessed the effect of mental stress on blood pressure (BP), heart rate (HR), and muscle sympathetic activity (MSA) before and after a triple espresso, intravenous caffeine, and placebo in the same subjects. Under baseline conditions, mental stress significantly increases MSA (+2.5+/-0.7 volts per minute; +14.1+/-10.3%), systolic (+11.6+/-4.1 mm Hg) and diastolic BP (+6.4+/-2.0 mm Hg), and HR (+9.6+/-1.8 minutes(-1)).
In nonhabitual coffee drinkers, a triple espresso, but not caffeine, induced an additional increase in systolic BP (+9+/-6.3 mm Hg; P=0.003) during mental stress, whereas in habitual drinkers, the stress-induced BP increase was blunted (+4+/-3.9 mm Hg; P=NS). As a result, nonhabitual coffee drinkers experienced significantly higher BP during mental stress than habitual drinkers (151+/-17.9/83+/-5.6 mm Hg versus 130+/-7.8/74+/-6.7 mm Hg; P<0.05).
Caffeine induced similar effects in habitual and nonhabitual coffee drinkers at rest and during mental stress. The response to the cold pressor test was not influenced by coffee drinking in both groups.
In conclusion, in nonhabitual coffee drinkers, coffee enhances the cardiovascular response to mental stress with an additional increase in systolic BP, whereas in habitual drinkers, the response is blunted. Caffeine alone does not exert any potentiating effect, confirming that ingredients other than caffeine are partially responsible for the stimulating effect of coffee on the cardiovascular system.
Are cognitive function and blood pressure related?
Viitanen M, Guo Z. Drugs Aging. 1997 Sep;11(3):165-9.Links
Division of Geriatric Medicine, Karolinska Institute, Huddinge Hospital, Sweden. Matti.Viitanen@cnsf.ki.se
In this article, we look at the literature concerning the relationship between blood pressure and cognitive function. If untreated, hypertension leads to stroke or cerebral infarction, and may therefore increase the risk of dementia or cognitive impairment. Patients with hypertension perform less well in some, but not all, cognitive tasks compared with normotensive individuals, even in the absence of overt stroke. The mechanisms underlying hypertension-related cognitive changes are complex and are not yet fully understood. Antihypertensive drug therapy may prevent cognitive decline, but no longitudinal studies have been performed to verify this in the general population. The relationship between blood pressure and cognition may be more complicated in the very old than in other age groups.
Hypertension