Is chronic structured exercise necessary for health?

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Endothelial dysfunction and cardiovascular disease.

Poredos P.

University Medical Centre Ljubljana, Department of Vascular Disease,

Slovenia. Pavel.Poredos@...

Healthy endothelium plays a central role in cardiovascular control.

Therefore endothelial dysfunction (ED), which is characterized by an

imbalance between relaxing and contracting factors, procoagulant and

anticoagulant substances, and between proinflammatory and

antiinflammatory mediators, may play a particularly significant role

in the pathogenesis of atherosclerosis and cardiovascular disease. ED

is thought to be an early physiologic event in the development of

atherosclerosis, occurring before morphologic changes in the vessel

wall can be detected. It is closely related to different risk factors

of atherosclerosis, to their intensity and their duration. The

involvement of risk factors in ED is also supported by results of

intervention studies that showed regression of ED with treatment of

risk factors. Further, it was shown that ED is significantly and

directly correlated with the occurrence of cardiac events. The common

denominator whereby different risk factors cause ED is most probably

increased oxidative stress and consequently decreased bioavailability

of nitrogen oxide. Endothelial dysfunction promotes atherosclerosis

and probably plays an important role in the development of thrombotic

complications in late stages of the disease. As ED is a key underlying

factor in the atherosclerotic process, markers of endothelial

abnormalities have been proposed, but loss of endothelium-dependent

vasodilation has became a broadly accepted indicator of endothelial

dysfunction. Using these non-invasive tests it is possible to follow

the dose-response of harmful effects or risk factors, and the effects

of preventive procedures on vessel wall function.

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1)Healthy endothelium plays a central role in cardiovascular control.

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Exercise training enhances endothelial function in young men.

son P, Montgomery HE, Mullen MJ, AE, Powe AJ, Bull T, Jubb

M, World M, Deanfield JE.

Cardiothoracic Unit, Great Ormond Street Hospital for Children NHS

Trust, London, United Kingdom.

OBJECTIVES: The present study was designed to assess whether exercise

training can enhance endothelium-dependent dilatation in healthy young

men. BACKGROUND: Exercise has been shown to reduce cardiovascular

morbidity and mortality, but the mechanisms for this benefit are

unclear. Endothelial dysfunction is an early event in atherogenesis,

and animal studies have shown that exercise training can enhance

endothelial function. METHODS: We have examined the effect of a

standardized, 10-week, aerobic and anaerobic exercise training program

on arterial physiology in 25 healthy male military recruits, aged 17

to 24 (mean 20) years, of average fitness levels. Each subject was

studied before starting, and after completing the exercise program.

Baseline vascular reactivity was compared with that of 20 matched

civilian controls. At each visit, the diameter of the right brachial

artery was measured at rest, during reactive hyperemia (increased flow

causing endothelium-dependent dilation) and after sublingual

glyceryltrinitrate (GTN; an endothelium-independent dilator), using

high-resolution external vascular ultrasound. RESULTS: At baseline,

flow-mediated dilatation (FMD) and GTN-mediated dilatation were

similar in the exercise and control groups (FMD 2.2+/-2.4% and

2.4+/-2.8%, respectively, p = 0.33; GTN 13.4+/-6.2 vs. 16.7+/-5.9,

respectively, p = 0.53). In the military recruits, FMD improved from

2.2+/-2.4% to 3.9+/-2.5% (p = 0.01), with no change in the

GTN-mediated dilation (13.4+/-6.2% vs. 13.9+/-5.8%, p = 0.31)

following the exercise program. CONCLUSION: Exercise training enhances

endothelium-dependent dilation in young men of average fitness. This

may contribute to the benefit of regular exercise in preventing

cardiovascular disease.

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2)Even young men (who have presumably have minimal damage due to their

young age) benefit from enhanced endothelial function from exercise.

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The effect of physical activity on endothelial function in man.

Moyna NM, PD.

Vascular Health Research Center, Dublin City University, Dublin, Ireland.

Endothelial dysfunction occurs early in the atherosclerosis in

response to elevated atherosclerotic risk factors, and endothelial

dysfunction itself may exacerbate the atherosclerotic process.

Treatments that reduce atherosclerotic risk factors also generally

improve endothelial function. The present review seeks to summarize

the effect of exercise training on endothelial function in human

subjects. Cross-sectional studies comparing healthy physically active

and inactive subjects as well as longitudinal exercise training

studies of healthy individuals show little effect of exercise training

on endothelial function. In contrast, both cross-section and

longitudinal studies document improved endothelial function with

exercise training in subjects with abnormal baseline endothelial

function, including the elderly and patients with heart failure or

coronary artery disease. Improvements in endothelial function with

physical activity may explain some of the benefits of exercise in

subjects with, or at risk for, vascular disease.

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3)Endothelial dysfunction may exacerbate the atheroslerotic process.

haven't I just shown good cause for the necessity of " fit " in the

definition of health??

FreeBird