What are Cardiovascular systems response to steady state exercise?

Answer 1

Cardiovascular

Upon steady state exercise the cardiovascular system will react in several ways,

Heart Rate: Typically during exercise heart rate will increase. This is in order to increase blood flow to the working muscles to allow for increased respiration - in order for the muscles to work efficiently. Prior to exercise the regular resting heart rate is around 60 - 80bpm but when you exercise the heart rate will go up from that because it's an initial response to the exercise. After a few minutes the heart rate will stop rising and stay constant. This is because the athlete has been jogging for example, continuously and isn't psychically exerting himself. This is known as steady-state heart rate where the demands of the active tissues can be adequately met by the cardiovascular system. However, there is an exception to this

During prolonged steady-state exercise, particularly in a hot climate, a steady-state heart rate will gradually increase. This phenomenon is known as cardiac drift and is thought to occur due to increasing body temperature

Cardiac output: Cardiac output is the amount of blood pumped by the heart in 1 minute measured in L/min. It is a product of stroke volume and heart rate (SV x HR). If either hearts rate or stroke volume increase, or both, cardiac output increases also. Cardiac output increases proportionally with exercise intensity. With steady state exercise changes in either heart rate or stroke volume will have an impact on the other component. The Heart rate and the stroke volume stops rising and becomes constant and Cardiac output does the same

Blood Flow: As you exercise, the blood vessels in your muscles dilate and the blood flow is greater, just as more water flows through a fire hose than through a garden hose. Your body has an interesting way of making those vessels expand. As ATP gets used up in working muscle, the muscle produces several metabolic by products (such as adenosine, hydrogen ions and carbon dioxide). These by products leave the muscle cells and cause the capillaries (small, thin-walled blood vessels) within the muscle to expand or dilate (vasodilatation). The increased blood flow delivers more oxygenated blood to the working muscle.

Blood that would have gone to the stomach or the kidneys goes instead to the muscles, and the way that happens shows how the body's processes can sometimes override one another. As your muscles begin to work, the sympathetic nervous system, a part of the automatic or autonomic nervous system (that is, the brainstem and spinal cord) stimulates the nerves to the heart and blood vessels. This nervous stimulation causes those blood vessels (arteries and veins) to contract or constrict (vasoconstriction). This vasoconstriction reduces blood flow to tissues. Your muscles also get the command for vasoconstriction, but the metabolic by products produced within the muscle override this command and cause vasodilatation,

Stroke volume: Stroke volume is the amount of blood ejected per beat from left ventricle and measured in ml/beat. Stroke volume to its highest during sub maximal exercise and doesn't increase during maximal exercise. The greatest increase of stroke volume increases in the transition from rest to moderate exercise, during maximal exercise stroke volume doesn't go over its peak of 120 - 140 per minute Starling's law states that the stroke volume is limited towards the venous return, of which is the amount of the blood that is available to enter the left atrium and pass to the left ventricle

By Tom Clarke

Answer 2

The neuromuscular system gets fatigued and the energy is lost