Whenever the human body needs to perform any physical work, the response is a series of physiological and mental changes that occur simultaneously, with each of these changes being integrated. Movement from one place to the other needs the muscular and skeletal system to get activated and work together, while when we eat the digestive system gets activated which itself involves a series of organ systems (Brown, Frontera, 2012) .The respiratory system on the other hand is continuously functioning but it also responds when we exercise by increasing the breath rate. The cardiovascular system also responds by altering the blood pumping rate when there is any intense physical activity. The duration and intensity of these session has a direct effect on the magnitude of these responses.
In the present report, we will be discussing about how the human body and the organ systems respond and adapt themselves to exercises and trainings. Thus, this work will provide a physiological basis to analyse the interdependence between exercises and physical health.
The physiological responses of the human body to exercises are mainly seen in cardiovascular systems, respiratory systems, muscular and skeletal systems and the immune system. These responses were studied in regulated laboratory settings. Here, exercise stress was accurately regulated and the response to those exercises was carefully observed.
Physical Activity and Health - Increased physical activity results in more oxygen requirements in the body and fast release of CO2 out of the body, as physical activities need energy which needs oxygen for the generation process. To be effective, the cardiovascular system has to respond to this increased physical activity (Goncalo, 2008). But the rate of blood pumping and respiration has a maximum limit. So, as the rate of muscular work increases, the above mentioned systems will reach their upper capacities, so they will no more be able to meet the demands.
Blood Flow and Blood Pressure - Blood flow pattern changes instantly when the body goes from rest to exercising. The skin and skeletal muscles receive only 20 percent of the blood flow output, when at rest but when exercising, more blood paves way for the active muscles, and the body temperature is increased. This results in even more blood flow to the skin. This is done by redistribution of blood flow, reducing flow to parts where there is low demand (Brown, Frontera, 2012). The arterial blood pressure is also increased during exercising. The systolic blood pressure increases continuously (maximum value of 200 to 240 mm of mercury) while the diastolic blood pressure remains at normal value.
Cardiovascular Responses to Exercise - The cardiovascular system consists of the heart, blood vessels and the blood. Keeping in mind some exceptions, the rate of blood flow from the heart is directly proportional to the breathing rate or the muscle’s oxygen demand and the need for oxygen is increased with increased physical activity. The Cardiac output increases with increase in oxygen demand, but only to its maximum capacity. To understand the scenario of cardiac output, stroke volume and heart rate change, a person exercising was taken into observation. In the process, cardiac output and heart rate increase with increase of work but stroke volume increases only to 40% to 60% of the person’s maximum oxygen intake (Brown, Frontera, 2012).
Respiratory Responses to Exercise - Pulmonary Ventilation is instantly increased mainly by stimulation of the respiratory centres in the brain stem by the motor cortex feedback from the joints and muscles of the limbs that are an active part of the exercise. As the exercising continues, the increased rate of work leads to increase in CO2 production and thus increase in body temperature. In a normal adult, the pulmonary ventilation car be as high as 100 litres per minute when exercising and as low as 10 litres per minute when at rest (Adams, Henry, Bernauer, 1974). For athletes, it can go as high as 200 litres per minute.
Skeletal Muscle Energy Metabolism - The main function of the muscular and skeletal system is for body movement. The oxygen extraction by the muscles is altered according to the demand, so that it can get rid of the waste products as fast as possible. The various metabolic processes within the human body generate Adenosine Triphosphate (ATP), which are the energy cells for the body. ATP is produced by three basic energy systems: the glycolytic system, the ATP-phosphocreatine (ATP-PCr) system and the oxidative system. The combustion in each of these systems is highly dependent on the rate of work and oxygen availability in the muscles (Adams, Henry, Bernauer, 1974).
Hormonal Responses to Exercises - The Endocrine system is the hormonal system of the body. It, along with the Nervous System combines the physiological responses with the hormonal responses during rest and exercise (Adams, Henry, Bernauer, 1974). During exercise, hormones such as catecholamines, are secreted at an increased rate, but insulin secretion is decreased. The hormonal system responds often differently for different sexes.
Physical activities have a lot of beneficial effects. They mostly effect the respiratory and cardiovascular system, but a significant effect is observed on the hormonal systems and the immune systems too as the body adapts to the continuous physical activities. An example is the blood pressure control for patients with hypertensive persons and the shaping of muscles for athletes who are in continuous practice. It is often observed that the effects of physical training diminish within a week or two if not resumed once stopped. The body of persons from all age groups continuously adapts to the trainings and physical activities.