Reduced Blood Flow To The Heart During Exercise

Your heart is a fine-tuned machine that is responsible for delivering oxygenated blood to the cells that need it. Your heart muscle is constantly working, getting only a break between each beat. Just like the other cells of the body, your cardiac cells must produce energy, and they require blood flow to do this. Without adequate blood flow back to the heart during exercise or supplying the cardiac cells, your heart must work harder, which may cause negative effects.

Cardiac Blood Flow During Exercise

The combination of an increase in heart rate, myocardial contractility and the work of the ventricles all call for an increase in the blood supply for the heart. According to a report by the American Physiological Society in 2008, the oxygen and blood flow demand of the ventricles increase substantially during exercise. In fact, there is a six-fold increase in demand by the left ventricle.

Disease

Coronary artery disease may affect the ability of blood to flow to the cardiac muscle cells during exercise. This disease is characterized by a reduction in blood flow due to an occlusion inside your artery. An occlusion inhibits blood flow, which can lead to an ischemia or infarction. During exercise, when your heart needs more blood, this is more apt to occur. Ischemia happens when your heart is not receiving the blood it needs --- you may also know this as a heart attack. Infarction is the irreversible damage done to heart muscle tissue from a lack of oxygenated blood. Infarction also reduces the blood flow to the heart.

Caffeine

Your intake of caffeine may also be enough to reduce blood flow to your heart during exercise, reports a study published in the "American Journal of Cardiology" in January 2006. Eighteen healthy subjects abstained from caffeine for 36 hours before the study was conducted. During the study, a dose of 200 mg of caffeine, or about two cups of coffee, was given to each participant. During rest and without caffeine, blood flow to the heart remained normal. However, during exercise, much needed blood flow to the heart was markedly decreased.

Cardiovascular Drift

A phenomena known as cardiovascular drift affects the blood flow to the heart during exercise, regardless of your fitness level or disease state. Cardiovascular drift occurs during a bout of prolonged upright exercise. This type of exercise reduces the venous return to the heart. Even though the demands for intensity remain the same, your heart rate must increase to keep up with the need for blood. Reduced venous return also means the heart must work harder to give itself the blood it needs.