For many true experimental designs, pretest-posttest designs are the preferred method to compare participant groups and measure the degree of change occurring as a result of treatments or interventions.
Itâs important to note that the flush caused by niacin is not harmful or dangerous. It is actually a sign of improved blood flow and circulation. Also niacin oxygenates the blood. When you get a niacin âflushâ it is an indication that the niacin is causing small blood vessels in your body to expand in size.Many of your small blood vessels, called capillaries, are so small that blood cells can only go through them in single file or if they are flexible enough to fold over.t is actually a sign of improved blood flow and circulation. Also niacin oxygenates the blood. When you get a niacin âflushâ it is an indication that the niacin is causing small blood vessels in your body to expand in size.
Arterioles are the smallest arteries in the body. They deliver blood to capillaries. Arterioles are also capable of constricting or dilating and, by doing this, they control how much blood enters the capillaries. Capillaries are tiny vessels that connect arterioles to venules.lood vessels also play a role in controlling your blood pressure. Blood vessels are found throughout the body. There are five main types of blood vessels: arteries, arterioles, capillaries, venules and veins. Arteries carry blood away from the heart to other organs.