Cardiovascular System And The Heart Rate

Exercise increases heart rate by a process of sympathetic autonomic stimulation. Sympathetic (adrenergic) nerves increase the excitability of the sino-atrial node and reduce the P-R interval .As exercise continues, the physiological changes in the body are continuously monitored by a number of physiological systems and the balance of activity of the sympathetic system (speeding up) and the parasympathetic system (slowing down) is constantly adjusted. When exercise is over, the heart rate does not drop immediately as the body has to undergo a period of re adaption to return to the resting state.

The cardiovascular response is triggered by excessive exercise within a short-term anaerobic exercise (such as running for 30 minutes). This initial response starts with the release of adrenaline that causes an increase in heart rate, meaning an increase in cardiac output. This activity

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1. What caused the change in HR with exercise? Muscles use more oxygen and glucose from the blood with increased movement. This produces wastes that decrease blood pH below the normal range causing an increase in heart rate. The heart rate increase delivers blood to the lungs and kidneys more quickly so these organs can remove the wastes from the body. The faster the muscles use energy and create waste, the faster the heart must pump blood. 2. Discuss the effect of venous

A parasympathetic response called Vasodilation happens. Blood vessels directing to the muscles dilate to allow more oxygen to be used. The blood pressure will drop because of the dilation. When we exercise our body will heat up causing blood vessels around our skin to dilate, more blood flows and help to reduce the excess heat in out body.

During exercise there is an increase in cardiac output, which corresponds to an increase in maximal oxygen consumption. With the increase in oxygen consumption, a greater increase in blood flow occurs. This means there is more oxygen circulating in the blood for the tissues to take up. Due to the increase in blood flow, vasoconstriction of arterioles occurs to maintain mean arterial pressure (Bassett & Edward, 1997). This limits oxygen consumption because some of the blood flow is directed to the brain and skin. It is further pointed out that the heart is another limiting factor because it determines how much blood and oxygen are supplied to the muscles especially when blood flow exceeds maximal cardiac output (Bassett & Edward,

As heart rate increases during exercise stroke volume will decrease, cardiac output is usually well maintained and the arterial blood pressure declines. Cardiovascular drift will sometimes be associated with a slight increase in the cardiac output directed to the vasodilated skin to increase blood flow to the skin to facilitate heat loss to the environment. According to Lori Cooper with Vanguard Endurance “the amount of blood the heart pumps out per minute (cardiac output) depends on the amount of blood that enters the heart (venous return), fills the ventricles (ventricular filling) and is ejected during heart contractions (stroke volume).” During cardiovascular drift the core temperature increase as heart rate increases, causing stroke volume to decrease to keep cardiac output and oxygen uptake remain the same. In a healthy adult their resting heart rate should be between 60 and 80 beats per minute. The heart rate of a

trained athletes will have a lower heart rate during this period of exercise. Recovery heart rates –

The effects of exercise on blood pressure, heart rate, respiration rate and electrical activity of the heart were assessed. The measurements of respiration rate, pulse rate and blood pressures were noted as described in Harris-Haller (2016). Data was first taken from subjects in a relaxed position and then followed by sets of reading after exercising based on one minute intervals. The data also noted sitting ECG traces from Harris-Haller (2016). The respiratory rate, pulse, blood pressure, P wave, QRS complex and T wave were defined for each subject. The class average was calculated for males and females and graphed to illustrate the results by gender for each cardiopulmonary factor.

People often exercise in elevated temperatures and maintain an intense work-out to improve their maximum conditioning levels. Participating in such exercise challenges the homeostasis of the human body. The way that the body reacts and adapts to physical stress depends on various components. Specifically, exercising in the heat can overload the body and decrease its capability to adapt to the stress that it is being put through (Nielsen, Hales, Strange, Christensen, Warberg, & Saltin, 1993). Compared to a more neutral environment, exercising in the heat results in alterations of the circulatory system, thermoregulatory system, and endocrine system (Nielsen, Hales, Strange, Christensen, Warberg, & Saltin, 1993). Despite these alterations, there are several guidelines that coaches and athletes should follow to allow the body a proper time frame to acclimate to the harsh temperatures , but the most effective practice is heat acclimation ten to fourteen days prior to the date of maximum exertion (Powers & Howley, 2015). Allowing the body time to acclimate and learn how to handle the stress from the heat, helps with acute and chronic adaptations. Being aware of how the heat effects the body and understanding the physiological responses as well as acute and chronic adaptations, should allow one’s body to safely and efficiently exercise during increased temperature.

As the intensity of exercise increased, so did the rates of the heart and breathing. After a small period of rest, the heart rate and breathing rate both decreased to a point close to their resting rate. This proved the stated hypothesis. First, the hearts average resting rate was recorded to be 76 bpm. The heart is therefore transporting oxygen and removing carbon dioxide at a reasonably steady rate via the blood. During the low intensity exercise (Slow 20) the heart rate increases to 107 bpm, which further increases to 130bpm at a higher intensity level (Fast 20). The heart therefore needs to beat faster to increase the speed at which oxygen is carried to the cells and the rate at which carbon dioxide is taken away by the blood.

Investigating the Effect of Exercise on Pulse Rate Aim: To see what happens to the pulse rate during exercise. Prediction: I predict that the pulse rate will increase in order to take more oxygen for respiration. The heartbeat will increase and become stronger to transport oxygen and carbon dioxide to and from the muscle cells. The breathing rate will increase in order to get rid of the extra waste such as Carbon dioxide. Respiration is the release of energy.

I predict that during exercise the heart and respiratory rate (RR) will increase depending on the intensity of exercise and the resting rates will be restored soon after exercise has stopped. I believe that the changes are caused by the increased need for oxygen and energy in muscles as they have to contract faster during exercise. When the exercise is finished the heart and ventilation rates will gradually decrease back to the resting rates as the muscles’ need for oxygen and energy will be smaller than during exercise.

The heart rate is a measurement of how many times the heart beats in a minute. Physically fit people tend to have a lower heart rate and during intense exercise tend to have lower rates as well. A decrease of heart rate at both rest and at fixed intensity of sub-maximal exercise [7] occurs a few months after an exercise program is begun. One’s heart rate reflects the amount of work the heart must do to meet an increase of demands of the body when engaged in activity. Heart Rate tends to increase proportionally with intensity oxygen uptake [16].

The muscles demand more energy and oxygen due to the increased workload that comes from exercise. This causes the heart rate and respiratory rate to increase in order to provide the required additional fuel to the muscles. In addition, the entire circulatory system works more efficiently due to vascular dilation and cholesterol reduction. By improving the condition of your cardiovascular fitness you are also helping yourself live longer, decrease the risk of heart disease, lower blood pressure, strengthen your cardiovascular system, and the list goes on. These reasons alone could save you from having heart disease.