[blindweightwatcher] fw Exercise Helps Your Heart - Even If You Eat Wrong The cells lining the interior of our bodies' blood vessels do more than just provide a smooth surface

From: "Jan Bailey" <jb021951@xxxxxxxxxxx>
To: <blindweightwatcher@xxxxxxxxxxxxx>
Date: Thu, 15 Jan 2009 17:23:10 -0600
Exercise Helps Your Heart - Even If You Eat Wrong The cells lining the interior 
of our bodies' blood vessels do more than just provide a smooth surface
over which blood cells can glide without forming dangerous blood clots. These 
vascular endothelial cells also regulate the tone and diameter of our blood
vessels, including the critical vessels that supply blood to the heart, brain, 
kidneys, and other vital organs.  

Complex biochemical feedback loops control the synthesis of nitric oxide and 
other chemicals from within the vascular endothelial cells, enabling blood
vessels to dilate up when the organs that they serve require additional blood 
flow. When this "demand-related" dilation of blood vessels is impaired, however,
vital organs, including the heart, can become starved of life-sustaining oxygen 
due to reduced blood flow (also known as ischemia). In addition to potential
ischemia, other adverse physiological effects are also associated with 
inadequate blood-vessel dilation, or vasodilation. These adverse factors include
an increase in vascular resistance that can strain the heart, an increased risk 
of potentially dangerous clots within blood vessels, and increased inflammatory
activity that can accelerate atherosclerosis (narrowing of the arteries) and 
organ damage.  

Story continues below . . .    

There are multiple known risk factors for decreased vascular endothelial cell 
function, including elevated cholesterol levels, high blood pressure, obesity,
diabetes, smoking, atherosclerosis, and increasing age. Interestingly, merely 
eating a fatty meal can rapidly induce vascular endothelial cell dysfunction,
leading to a decrease in nitric oxide synthesis by these cells. When this 
happens, arteries become stiff and can no longer dilate up to provide increased
blood flow when required.  

When coronary arteries are already narrowed and diseased by atherosclerosis, a 
sudden loss of nitric oxide from endothelial cells can result in a critical
lack of blood supply to the heart's muscle, causing myocardial ischemia, as 
well as the formation of blood clots within severely narrowed coronary arteries.
This, in turn, can result in a complete obstruction of the coronary arteries, 
causing a heart attack (myocardial infarction). Similar events can occur
in the brain, causing a stroke.  

It is known that vigorous exercise can improve vascular endothelial cell 
function, although the precise mechanisms at work are not entirely understood at
this time. However, just as regular and vigorous exercise helps to keep our 
bodies looking and feeling young, overall, so does exercise also appear to
keep our blood vessels young, supple, and able to dilate up to provide 
increased blood flow when required. Now, a newly published study in the Journal
of the American College of Cardiology looks at the ability of exercise to 
prevent vascular endothelial dysfunction following a fatty meal.  

In this study, eight healthy adult males were fed high-fat meals. All patient 
volunteers underwent vascular testing before and after consuming the high
fat meals in order to assess the level of endothelial cell dysfunction in the 
artery that supplies the arm. The experiment was varied such that each high-fat
meal was preceded by either a 16 to 18 hour period of rest, a similar period of 
moderate-intensity exercise, or by a similar period of high-intensity exercise.
The ability of the brachial artery to dilate up under conditions requiring 
increased blood flow was then measured under each of these three experimental
conditions.  

Following consumption of a high-fat meal, the brachial arteries of the men who 
had rested before eating narrowed, on average, by about 10 percent from their
pre-meal baseline diameter, confirming the onset of significant endothelial 
cell and arterial dysfunction. The men who engaged in moderate-intensity 
exercise
prior to their super-sized meals also experienced a 10 percent reduction in the 
diameter of their brachial arteries after consuming their high-fat meals,
just like the men who rested before they ate.  

However, even these moderate levels of exercise did restore some (but not all) 
of their arteries' ability to dilate in response to increased blood flow
requirements, whereas there was no return of this flow-mediated vasodilation in 
the arteries of the men who had rested prior to eating. Among the men who
engaged in vigorous, high-intensity exercise prior to chowing down, however, 
arterial dilation in response to increased blood flow was preserved even after
a high-fat meal. This protective effect of high-intensity exercise on vascular 
endothelial function following a high-fat meal occurred despite laboratory
evidence of increased fat and cholesterol levels in the blood of these same men 
after eating.  

While I am certainly not suggesting that it is safe to gorge on high-fat foods 
as long as you exercise like a maniac before you eat, this clinical study
nonetheless suggests that at least one adverse cardiovascular effect acutely 
associated with eating a fatty meal can be substantially prevented with exercise
but only when that exercise is performed before eating, and at a very high 
intensity level.  

On the other hand, this research study cannot provide any reasonable assurance 
that all of the other adverse and life-threatening health effects of high-fat
diets (including cancer) can be prevented by exercising before meals, even if 
you exercise like crazy!
[blindweightwatcher] fw Exercise Helps Your Heart - Even If You Eat Wrong The cells lining the interior of our bodies' blood vessels do more than just provide a smooth surface

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