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ACUTE PHYSIOLOGICAL RESPONSES TO EXERCISE (MUSCULAR More oxygen UTILIZED…
ACUTE PHYSIOLOGICAL RESPONSES TO EXERCISE
CARDIO RESPONSES
More oxygen TRANSPORTED to working muscles for aerobic energy production (stroke volume, heart rate, cardiac output)
HEART RATE
number of contractions of the heart muscle within a minute
the heart pumps oxygenated blood around the body with each beat. an increase in heart rate results in more contractions per minute and therefore a greater amount of blood is delivered/transported for diffusion and used by working muscles for aerobic energy production. some individuals may also record a rise in heart rate before exercise commences due to the body’s anticipation of exercise. this is referred to as ‘anticipatory rise’.
STROKE VOLUME
a measure of the amount of blood ejected from the left ventricle of the heart each contraction
the heart pumps oxygenated blood around the body wiht each beat. an increase in stroke volume results in more blood pumped per contraction and therefore a greater amount of blood is delivered/transported for diffusion and use by working muscles for aerobic energy production.
CARDIAC OUTPUT
the total amount of blood ejected by the left ventricle of the heart each minute. it is calculated by multiplying heart rate and stroke volume. Q = HR X SV
the heart pumps oxygenated blood around the body. an increase in cardiac output results in more blood pumped per minute and therefore a greater amount of blood is delivered/transported for diffusion and use by working muscles for aerobic energy production.
VASCULAR RESPONSES
More oxygen TRANSPORTED to working muscles for aerobic energy production (stroke volume, heart rate, cardiac output)
VENOUS RETURN
blood pressure is the pressure exerted by the blood against the walls of the arteries when the heart contracts and relaxes
blood pressure is split into two phases - systolic and diastolic. systolic phase is the pressure on the artery walls during the contraction phase of the heart cycle; this will always be the higher of the two values and increases with all types of exercise. diastolic blood pressure is the pressure on the artery wall during the relaxation phase of the heart cycle. during whole body continuous exercise, the diastolic will stay the same, however, during resistance types of exercise the diastolic value will increase.
REDISTRIBUTION OF BLOOD FLOW TO THE MUSCLES
redirection of the blood away from major organs and towards the working muscles.
the redistribution of blood can be achieved through the mechanisms of vasodilation and vasoconstriction. vasodilation involves the blood vessels expanding their diameter to let more blood through to the working muscles. vasoconstriction involves the blood vessels constricting to allow less blood to be pumped to major organs.
REDISRTIBUTION OF BLOOD FLOW TO THE SKIN (THERMOREGULATION)
thermoregulation aims to regulate the body temperature of a person and involves the body vasodilating blood vessels near the skin to help cool the blood, however, this causes a decrease in performance due to less blood being available at the working muscles.
DECREASED BLOOD VOLUME
total amount of blood may decrease during exercise as a result of sweating and is actually caused by a decrease in plasma volume.
RESPIRATORY
Make oxygen AVAILABLE in the lungs to be diffused into the blood (ventilation, tidal volume, respiratory frequency)
RESPIRATORY FREQUENCY
the amount of breaths taken per minute. also known as breathing or respiratory rate
increases the availability of oxygen that can be diffused into the bloodstream via the alveolar-capillary interface. therefore increasing oxygen delivery to the working muscles for aerobic energy production.
TIDAL VOLUME
depth of each breath
increases the availability of oxygen that can be diffused into the bloodstream via the alveolar-capillary interface. therefore increasing oxygen delivery to the working muscles for aerobic energy production.
VENTILATION
amount of air inspired and expired per minute by the lungs. it is a product of multiplying respiratory frequency X tidal volume. V = RF X TD
increases the availability of oxygen that can be diffused into the bloodstream via the alveolar-capillary interface. therefore increasing oxygen delivery to the working muscles for aerobic energy production.
PULMONARY DIFFUSION
movement of oxygen and carbon dioxide from an area of high concentration to an area of low concentration.
occurs at the alveolar-capillary interface. after inspiration, oxygen moves from an area of high concentration in the lungs to and area of low concentration in the blood. carbon dioxide moves from an area of high concentration in the blood to an area of low concentration in the lungs to be expired. an increase in pulmonary diffusion provides a greater amount of oxygen delivered to the working muscles and greater removal of carbon dioxide.
MUSCULAR
More oxygen UTILIZED at the working muscles for aerobic energy production (a-VO2 diff, muscle enzyme activity
ARTERIO-VENOUS DIFFERENCE (AVO2-DIFF)
the measure of the difference of the oxygen concentration in the arterial blood and venous return
increase in the amount of blood that is delivered and utilised by the muscle to produce energy production.
MOTOR UNIT RECRUITMENT AND MUSCLE FIBRE RECRUITMENT
during exercise more muscular contractions are required to move the skeletal muscle to create movement. the greater the demands for exercise the greater the needs for muscular contraction. the body responds by increasing the firing of the motor neurons and the muscle fibres it stimulates. the greater the amount of motor units that are recruited the greater the force it stimulates.
fast with fibres contract faster and create more force than slow twitch fibres.
MUSCLE TEMPERATURE
an increase in the amount of blood flowing to the muscles and the heat created as a by-product of aerobic respiration, causes the muscle to increase in temperature.
MUSCLE ENZYME ACTIVITY
enzymes are substances that are in the muscle which accelerate the chemical reactions. an increase in the enzyme activity in the body will result in the great ability to produce energy.
DECREASED MUSCULAR SUBSTRATE LEVELS
as a result of exercise, muscular stores of ATP (around 2 seconds), PC (around 10 seconds), glycogen (around 2 hours), and triglycerides (around 4 hours) will start to deplete. when these deplete, it has a negative impact on the body’s ability to make energy.