PHED 1 Applied Physiology Responses to Exercise AS PE PHED 1 Applied Physiology Responses to Exercise

HEART DYNAMICS AVERAGE RESTING HEART RATE VALUES MALES - 70 bpm The Resting Heart HEART DYNAMICS AVERAGE RESTING HEART RATE VALUES MALES - 70 bpm FEMALES - 72 bpm CARDIAC OUTPUT = SV x HR (this is the formula used for each calculation) SV = stroke volume - measured in ml (cm3) AT REST untrained person endurance athlete = 75 (ml) x 70 (bpm) = 109 (ml) x 48 (bpm) = 5.25 l min-1 = 5.23 l min-1 DURING MAXIMAL EXERCISE untrained person endurance athlete = 120 (ml) x 200 (bpm) = 190 (ml) x 200 (bpm) = 24 l min-1 = 38 l min-1

TRAINING AND PERFORMANCE ADAPTATIONS PRODUCED BY AEROBIC TRAINING CARDIAC RESPONSE blood plasma volume increases with training therefore increased blood plasma volume enters left ventricle increasing the stretch of the ventricular walls by the Frank-Starling mechanism (starlings law ) cardiac hypertrophy – heart becomes bigger and stronger (mainly left ventricle) increased ventricular muscle mass and stronger elastic recoil of the myocardium causes a more forceful contraction during ventricular systole therefore stroke volume increases and HR decreases (bradycardia) and hence providing more oxygen per pulse Ejection Fraction is greater the net effect is up to 20% bigger stroke volume and greater oxygen delivery to muscles

TRAINING AND PERFORMANCE ADAPTATIONS PRODUCED BY AEROBIC TRAINING cardiovascular system becomes more efficient VASCULAR RESPONSE more haemoglobin is created and is available in blood for oxygen transport there is increased capillarisation of trained muscle hence increase in a-vO2 diff increased elasticity and thickness of smooth muscle of arterial walls makes walls tougher and therefore less likely to stretch under pressure this maintains blood pressure forcing blood through capillary network BLOOD VESSELS IN THE HEART blood flow to heart decreases because heart muscle is more efficient hence decrease in resting HR

Cardiovascular Drift Page 57 of text book As exercise continues stroke volume drops ? We sweat, blood loses plasma, venous return drops – starlings law HR increases to compensate Cardiac output starts to increase – we need more O2 to cool down the body

TRAINING AND PERFORMANCE ADAPTATIONS PRODUCED BY AEROBIC TRAINING RESPIRATORY RESPONSE decrease in breathing rate (f) at submaximal workloads and increase in breathing rate (f) at maximal workloads hence large increase in volume of air breathed per minute increase in pulmonary blood flow and plasma volume efficiency of alveoli improves, and more alveoli are utilised hence increased gaseous exchange RECOVERY improved oxygen recovery with better muscle capillarisation and efficient cool-down, lactic acid removal is improved

ARTERIOVENOUS OXYGEN DIFFERENCE Respiratory Response to Exercise ARTERIOVENOUS OXYGEN DIFFERENCE a-vO2 diff this expresses the difference between the oxygen carried by blood in arteries and veins and represents the amount of oxygen delivered to working tissue in the capillary system a-vO2 diff - AT REST venule capillary arteriole blood flow 15ml O2 per 100ml blood 20ml O2 per 100ml blood a-vO2 diff = 5ml per 100ml blood a-vO2 diff - DURING INTENSE EXERCISE venule capillary arteriole blood flow 5ml O2 per 100ml blood 20ml O2 per 100ml blood a-vO2 diff = 15ml per 100ml blood

TRAINING AND PERFORMANCE ADAPTATIONS PRODUCED BY AEROBIC TRAINING pulmonary systems become more efficient RESPIRATORY RESPONSE musculature of torso becomes stronger and more efficient lung volumes increase slightly, greater volumes of air can be breathed per breath increase in VC at the expense of RV

Big words you must know Starlings Law Cardiovascular Drift Stroke Volume Bradycardia Cardiac Output Capillarisation Ejection Fraction Ventricular Systole Venous Return Anticipatory Rise A – Vo2 Diff Cardiac Hypertrophy

Practice Questions Jan 2011 Paper June 2011 Paper