Acute Responses to Exercise: Summary Table

by steveking1010 (student)

GCSE Physical Education (Sport & Coaching)

Acute Responses to Exercise: Summary ResponseDefinitionType of ResponseEffect of ExerciseThe benefit of this response / why it happensHow it occursVentilationThe amount of air breathed in and out per minute. The product of Tidal Volume (TV) x Respiratory Rate (RR)RespiratoryIncreasesTo increase the volume of oxygen in the lungs that can be diffused into the blood and transported to the working musclesGreater contraction of the intercostal muscles and diaphragmDiffusionThe movement of oxygen and carbon dioxide from an area of high concentration to an area of low concentration. Occurs in the alveoli of the lungs and the muscle capillaries.Respiratoryand CirculatoryIncreased CapacityIn order to increase the transfer or oxygen into the blood stream and delivery to the muscle cells. Also, to dispose of carbon dioxide which is produced as a result of the aerobic energy systemCaused by an increased surface area of the alveoli and muscle tissueCardiac Output (Q)The product of Stroke Volume (SV) x heart rate (HR). The amount of blood pumped out of the left ventricle per

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minuteCardiovascularIncreasesSo that more blood can be ejected out of the heart per minute and therefore more oxygen can be delivered to the working musclesCaused by a stronger ventricular contraction – results in more blood being ejectedBlood PressureThe amount of pressure exerted on the arteries when the ventricles contract (systolic) and relax (diastolic)CardiovascularSystolic increases, diastolic stays the sameBecause more blood is being pumped out per beat/minute and therefore it causes an increase in pressure Through an increase in Cardiac OutputBlood VolumeThe amount of volume of bloodCardiovascularDecreasesAs a consequence of sweatingCaused by a decrease in plasma volume due to sweating. Depends on the intensity, duration and environmental factorsVenous ReturnThe amount of blood that is returned back to the heart via the veinsCardiovascularIncreasedSo that an increase in cardiac output can take place. With more blood being delivered to the heart more can be pumped back out again for the delivery of oxygen to the muscles and carbon dioxide to the lungsThree mechanisms:The muscle pump (muscular contractions)The respiratory pump (diaphragm increases abdominal pressure) – veins in thorax and abdomen emptied towards heartVeno constriction (constrictions of the veins)Redistribution of blood flowThe redirection of blood away from areas where it is not needed (e.g. spleen, kidneys) to areas where it is (e.g. working muscles)CardiovascularRedistributionTo increase the amount of oxygen being delivered to the organs that need it during exercise (e.g. working muscles)Increasing blood flow to the skin assists in the regulation of body temperature through heat exchange with environmentVasoconstriction occurs in arterioles supplying oxygen to the inactive areas and vasodilation occurs in arterioles supplying oxygen to the working musclesOxygen Consumption (VO2) / Arterio-Venous Oxygen Difference (A-VO2 diff.)The volume of oxygen that can be taken up and used by the body.The difference in oxygen concentration in the arterioles compared to the venules.CardiovascularIncreasesTo increase the amount of oxygen that is delivered and used by the working musclesCaused by an increase in cardiac output and the amount of oxygen extracted from the blood into the muscle capillariesIncreased blood flow to working musclesThe amount of blood that is delivered to the working musclesMuscularIncreasesTo deliver more blood to the working muscles and therefore more oxygenCaused by the opening (dilation) or skeletal capillaries. This:Allows more blood to flow to the musclesResults in a larger blood volume reaching the muscle (but not an increase in velocity)Increases the surface area resulting in increased diffusion ratesLactateA bi-product of anaerobic glycolysisMuscularIncreases at the start of exercise and then remains constant when production = removalIncreases past the lactate inflection pointIt is produced at the start of exercise because the body cannot deliver enough oxygen to the working muscles to resynthesis ATP aerobically.It remains constant when its rate of production = removal, but if it is being produced faster than it is being removed then it will continue to riseAs a result of ATP resynthesis via anaerobic glycolysisMotor Unit recruitmentA motor neuron and the muscle fibres it stimulatedMuscularIncreased number recruited / increase frequency of messagesTo enable the correct number of muscle fibres to be recruited depending on the intensity of the activity – ‘all or nothing principle’. If a motor unit receives the impulse, all its fibres will contractBy electrical impulse signals that are sent from the central nervous system (brain and spinal cord)Energy SubstratesThe chemicals that are required to resynthesis ATP i.e. PC, glycogen, triglyceridesMuscularDecreaseOnce ATP stores are depleted, PC, muscle glycogen and muscle triglycerides are all used to resynthesise ATP and so they get used upAs a result of the three energy systems which are used to resynthesise ATPBody TemperatureA change in the internal temperature of the bodyMuscularIncreases until it is controlled bySweat glands produce sweatIncreased blood flow to skin (via vasodilation)Mechanisms work to prevent an increase in core body temperature.(However, during high intensity, blood vessels vasoconstrict which hinders heat transfer)Heat is a by-product of converting chemical energy into mechanical energy