The figure to the right illustrates the FMD findings for exercise. These results were not expected. Findings from the literature indicates that FMD

• Silvestro et al. Atherosclerosis 165:277-283,2002
  • 12.9+1.1 to 14.1+1.4% immediately following maximal exercise in healthy adults
• Harvey, P.J. et al. Journal of Hypertension 23:285-292, 2005
  • pre- & 45 min post exercise: 45 min treadmill walking at 60%
  • 5.3+1.3 to 9.9+1.4 in post-menopausal women
  • 12.1+1.5 to 14.4+1.2 in pre-menopausal women

It is difficult to interpret our laboratory findings. Essentially there was no change in FMD immediately following exercise. There was an increase in FMD for the man and a decrease for the woman at 30 min post. Whether these differences could be in training, relative exercise intensity, sex, artery size, race, or error is unknown at this time.

The possible mechanisms proposed to increase FMD following exercise could be:

• an increase in exercise induced shear stress from the increased blood flow of exercise
• a decrease in oxidative or inflammatory mediators associated with the exercise

The Figure to the left illustrates the sex difference in the diameters of the brachial artery. The men exhibit larger artery diameters than the women. These differences can probably be attributed to larger structure, i.e. more muscle mass, found in men. The larger structures would be precipitated by an increased flow for supply/demand for the men.

The different functions of the endothelium include:

• Protect the intima and media from foreign invaders.
• Provide anti- coalgulant properties for platelets on the endothelial wall.
• Prevent adhesion of leukocytes or platelets to the wall of the artery
• Control of tissue permeability, allowing specific molecules to pass through the endothelium. (i.e. LDL)
• Production of vasodilating molecues such as Nitric Oxide to keep the artery patient

Endothelial function is a better measure of the risk for cardiovascular disease than the traditional risk factors. The most common cardiovascular disease is atherosclerosis. This process invades the artery wall and deposits cholesterol and other products into the wall until the lesion protrudes into the artery. A clinical event such as a heart attack or stroke is the end point of this disease. Although the disease is realted to risk factors such as high cholesterol, hypertension, smoking and physical inactivity, 50% of the patients who have a heart attack do not have high cholesterol or other risk factors. Therefore, a direct measurement of the artery health (i.e. endothelial function) is a better predictor of disease than measuring each of the risk factors.

Other disease populations that exhibit endothelial dysfunction are listed below. The exerise effects on FMD for these populations are also listed below:

Aging is another condition that compromises endothelial function. The natrual aging process is a gradual loss of arterial compliance, mostly through increased stiffening. Exercise may have a role in improving endotheilal dysfunction associated with aging. The exercise factors include:

• increases in elastin
• lesser cross-linking
• increased NO bioavailability
• indirect effect on risk factors

Besides exercise, antioxidants and anti-inflammatory drugs have a positive effect on the endothelium. Antioxidants can be obtained by diet or dietary supplements.

Other ways can endothelial function be measured includes:

• Pulse Wave Velocity
• Arterial Stiffness
• Pulse Contour Analysis
• Forearm Plethysmography
• Coronary Artery Angiography
• PET Scans
• Biomarkers