Cardiovascular system Cardiovascular control during exercise Major cardiovascular functions §Delivery (e.g., oxygen and nutrients) §Removal (e.g., carbon dioxide, lactate, other waste products) §Transportation (e.g., hormones) §Maintenance (e.g., body temperature, pH) §Prevention (e.g., infection—immune function) Cardiovascular system §A pump – the heart §A system of channels – the blood vessels §A fluid medium - blood Heart anatomy • https://www.gettyimages.com/detail/illustration/anatomy-of-heart-interior-frontal-section-royalty-f ree-illustration/188057943 • Heart anatomy Key points §The two atria receive blood into the heart; the two ventricles send blood from the heart to the rest of the body. §The left ventricle has a thicker myocardium due to hypertrophy resulting from the resistance against which it must contract. Heart Rate •Resting heart rates in adults tend to be between 60 and 85 beats/min. However, extended endurance training can lower resting heart rate to 35 beats/min or less. This lower heart rate is thought to be due to decreased intrinsic heart rate and increased parasympathetic stimulation. • What is the average resting heart rate frequency? Heart Rate •Resting heart rates in adults tend to be between 60 and 80 beats/min. However, extended endurance training can lower resting heart rate to 40 beats/min or less. This lower heart rate is thought to be due to decreased intrinsic heart rate and increased parasympathetic stimulation. • Cardiac Arrhythmias •BRADYCARDIA – Resting heart rate below 60 beats/min •TACHYCARDIA – Resting heart rate above 100 beats/min •PREMATURE VENTRICULAR CONTRACTIONS (PVCs) – feels like skipped or extra beats •VENTRICULAR TACHYCARDIA – three or more consecutive PVCs that can lead to ventricular fibrillation in which contraction of the ventricular tissue is uncoordinated Cardiac cycle Diagram Description automatically generated §The event that occurs between two consecutive heartbeats (systole to systole) § §Diastole—relaxation phase during which the chambers fill with blood - 62% of cycle duration §Systole—contraction phase during which the chambers expel blood - 38% of cycle duration https://en.wikipedia.org/wiki/Cardiac_cycle#/media/File:2027_Phases_of_the_Cardiac_Cycle.jpg Diagram Description automatically generated Stroke Volume and Cardiac Output •Stroke volume (SV) is volume of blood pumped per contraction •Average 50-100 ml •End-Diastolic Volume (EDV) – blood volume in a ventricle before contraction •End-Systolic Volume (ESV) – blood volume in a ventricle after contraction •SV = EDV – ESV •Cardiac output (Q) is the total volume of blood pumped by the ventricles per minute • Blood distribution A picture containing bubble chart Description automatically generated Diagram Description automatically generated https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4551211/ https://physoc.onlinelibrary.wiley.com/doi/10.1113/JP270593 Blood pressure Shape, arrow Description automatically generated Table Description automatically generated with medium confidence §Systolic blood pressure (SBP) is the highest pressure and diastolic blood pressure (DBP) is the lowest pressure §Mean arterial pressure (MAP)—average pressure exerted by the blood as it travels through arteries §MAP = DBP + [0.333 ´ (SBP – DBP)] § § §Rest Blood Pressure is about 120/80 § §Hypertension: BP = more than 140/90 §Hypotension: BP = less than 90/60 https://medical.andonline.com/systolic-vs-diastolic-blood-pressure/ Parameters affected by training §Heart size §Stroke Volume §Heart rate §Cardiac output §Blood flow §Blood pressure §Blood volume Cardiovascular Response to Acute Exercise •Heart rate (HR) increases as exercise intensity increases up to maximal heart rate •Stroke volume (SV) increases up to 40% to 60% VO2max in untrained individuals and up to maximal levels in trained individuals. •Increases in HR and SV during exercise cause cardiac output (Q) to increase •Blood flow and blood press •All result in allowing the body to efficiently meet the increased demands placed on it Resting and Maximum Heart Rate •RHR •Averages 60 to 80 beats/min; can range from 28 to above 100 beats/min •Tends to decrease with age and with increased cardiovascular fitness •Is affected by environmental conditions such as altitude and temperature • •HRmax •The highest heart rate value one can achieve in an all-out effort to the point of exhaustion •Remains constant day to day and changes slightly from year to year •Can be estimated: •HRmax = 220 – age in years or •HRmax = 208 – (0.7 x age) • Arrow: Counter-clockwise curve outline Arrow: Clockwise curve outline https://www.mayoclinic.org/healthy-lifestyle/fitness/in-depth/exercise-intensity/art-20046887#:~:te xt=Subtract%20your%20age%20from%20220,minute%20for%20the%20average%20adult. Heart Rate and Intensity Arrow: Counter-clockwise curve outline https://www.mayoclinic.org/healthy-lifestyle/fitness/in-depth/exercise-intensity/art-20046887#:~:te xt=Subtract%20your%20age%20from%20220,minute%20for%20the%20average%20adult. Heart Rate and Training https://www.mayoclinic.org/healthy-lifestyle/fitness/in-depth/exercise-intensity/art-20046887#:~:te xt=Subtract%20your%20age%20from%20220,minute%20for%20the%20average%20adult. Resting Heart Rate •Decreases with endurance training likely due to more blood returning to heart and changes in autonomic control •Sedentary individuals can decrease RHR by 1 beat/min per week during initial training, but several recent studies have shown small changes of less than 3 beats/min with up to 20 wk of training •Highly trained endurance athletes may have resting heart rates of 30 to 40 beats/min Arrow: Clockwise curve outline https://www.mayoclinic.org/healthy-lifestyle/fitness/in-depth/exercise-intensity/art-20046887#:~:te xt=Subtract%20your%20age%20from%20220,minute%20for%20the%20average%20adult. Heart Rate During Exercise •SUBMAXIMAL •Decreases proportionately with the amount of training completed •May decrease by 10 to 30 beats/min after 6 months of moderate training at any given rate of work, with the decrease being greater at higher rates of work • •MAXIMAL •Remains unchanged or decreases slightly •A decrease might allow for optimal stroke volume to maximize cardiac output https://www.mayoclinic.org/healthy-lifestyle/fitness/in-depth/exercise-intensity/art-20046887#:~:te xt=Subtract%20your%20age%20from%20220,minute%20for%20the%20average%20adult. Heart Rate Recovery Period •The time after exercise that it takes your heart to return to its resting rate •With training, heart rate returns to resting level more quickly after exercise •Has been used as an index of cardiorespiratory fitness •Conditions such as altitude or heat can affect it •Should not be used to compare individuals to one another Heart Rate Recovery Period and Training Stroke Volume •Determinant of cardiorespiratory endurance capacity at maximal rates of work •Increases with increasing rates of work up to intensities of 40% to 60% of max or higher •May continue to increase up through maximal exercise intensity, generally in highly trained athletes •Magnitude of changes in SV depends on position of body during exercise Stroke Volume and Intensity Stroke Volume and Training •Stroke Volumes (SV) for Different States of Training • •Subjects SVrest (ml) SVmax (ml) •Untrained 50-70 80-110 •Trained 70-90 110-150 •Highly trained 90-110 150-220 • Changes in Q and SV with Increasing Rates of Work Cardiac Output §Resting value is approximately 5.0 L/min. §Increases directly with increasing exercise intensity to maximal values of between 20 to 40 L/min §The magnitude of increase varies with body size and endurance conditioning. §When exercise intensity exceeds 40% to 60%, further increases in Q are more a result of increases in HR than SV since SV tends to plateau at higher work rates. Cardiac Output and Intensity Cardiac Output and Training Changes in HR, SV, and Q with Changes in Position and Exercise Intensity Blood Pressure §Cardiovascular Endurance Exercise §Systolic BP increases in direct proportion to increased exercise intensity §Diastolic BP changes little if any during endurance exercise, regardless of intensity § §Resistance Exercise §Exaggerates BP responses to as high as 480/350 mmHg Blood Pressure Responses Cardiovascular Adaptations to Training §Left ventricle size and wall thickness increase §Resting, submaximal, and maximal stroke volume increases §Maximal heart rate stays the same or decreases §Cardiac output is better distributed to active muscles and maximal cardiac output increases §Blood volume increases, as does red cell volume, but to a lesser extent §Resting blood pressure does not change or decreases slightly, while blood pressure during submaximal exercise decreases Heart rate measurements • Measuring Heart Rate Measuring Heart Rate Blood pressure measurements Blood §Connective tissue (the only fluid tissue in the body) §Accounts for approx. 7% of body weight §An adult individual has approx. 5liters of blood §Blood composition §Plasma (55%) §91% water §8% proteins – albumin, globulin (transportation) §1% other molecules §Formed elements (45%) §99% red blood cells (erythrocytes) – carry oxygen §<1% white blood cells (leukocytes) – protect from pathogens §Platelets (<1%) Diagram Description automatically generated with medium confidence Blood placed in a centrifuge Line arrow: Counter-clockwise curve with solid fill * Erythrocytes and platelets do not possess all the typical organelles and they can not divide – they are replaced by stem cells in the bone marrow https://www.khanacademy.org/science/biology/human-biology/circulatory-pulmonary/a/components-of-the -blood https://www.youtube.com/watch?v=yj7bfZKlIp8&t=182s&ab_channel=ProfessorDaveExplains Blood hematocrit, viscosity §Blood viscosity = thickness of the blood §The more viscous, the more resistant to flow §Higher hematocrits result in higher blood viscosity https://www.khanacademy.org/science/biology/human-biology/circulatory-pulmonary/a/components-of-the -blood Blood functions §Delivers oxygen to tissues §Delivers nutrients such glucose, amino acids or fatty acids – dissolved in blood or attached to carrier proteins §Transports waste products – CO2, Urea, Lactic acid §Transports hormones §Protects from pathogens (Immunological functions) – white blood cells, Antibodies §Regulates temperature §Buffers and balances acid base homeostasis §Coagulation (to stop bleeding) Hemoglobin (Hb) Diagram Description automatically generated A picture containing colorful Description automatically generated §Hb comprises 4 globin subunits – two α and two β units §Each globin is attached to a heme b group with an iron atom at the center §Each heme b group can carry one oxygen molecule attached to the iron atom §Hb is present in two forms (influenced by partial pressures and pH) §Relaxed (R) §Tense (T) §Different absorption spectra - used for oxygen levels measurements Heme b group Shape Description automatically generated with medium confidence Various factors such as low pH, high CO[2] and high 2,3 BPG at the level of the tissues favor the taut form, which has low oxygen affinity and releases oxygen in the tissues. Conversely, a high pH, low CO[2], or low 2,3 BPG favors the relaxed form, which can better bind oxygen.^[54] The partial pressure of the system also affects O[2] affinity where, at high partial pressures of oxygen (such as those present in the alveoli), the relaxed (high affinity, R) state is favoured. Inversely, at low partial pressures (such as those present in respiring tissues), the (low affinity, T) tense state is favoured.^[55] Additionally, the binding of oxygen to the iron(II) heme pulls the iron into the plane of the porphyrin ring, causing a slight conformational shift. The shift encourages oxygen to bind to the three remaining heme units within hemoglobin (thus, oxygen binding is cooperative). Hemoglobin (Hb) Diagram Description automatically generated A picture containing colorful Description automatically generated §Approx. 250 million Hemoglobin molecules per one red blood cell! §100 ml of blood contains ~14-18 g of Hb in men and ~12-14 in women (1 g of Hb combines with 1.34 ml of oxygen) §There are ~20.1 ml of O2 per 100 ml of arterial blood (15 g of Hb x 1.34 ml of O2/g of Hb) in men and ~17.4 ml of O2 per 100 ml of arterial blood (13 g x 1.34) in women §Low iron leads to iron-deficiency anemia, reducing the body’s capacity to transport oxygen—this is more of a problem in women than men Heme b group Shape Description automatically generated with medium confidence Various factors such as low pH, high CO[2] and high 2,3 BPG at the level of the tissues favor the taut form, which has low oxygen affinity and releases oxygen in the tissues. Conversely, a high pH, low CO[2], or low 2,3 BPG favors the relaxed form, which can better bind oxygen.^[54] The partial pressure of the system also affects O[2] affinity where, at high partial pressures of oxygen (such as those present in the alveoli), the relaxed (high affinity, R) state is favoured. Inversely, at low partial pressures (such as those present in respiring tissues), the (low affinity, T) tense state is favoured.^[55] Additionally, the binding of oxygen to the iron(II) heme pulls the iron into the plane of the porphyrin ring, causing a slight conformational shift. The shift encourages oxygen to bind to the three remaining heme units within hemoglobin (thus, oxygen binding is cooperative). Blood KEY POINTS §Blood and lymph transport materials to and from body tissues §Blood is about 55% to 60% plasma and 40% to 45% formed elements (white and red blood cells and blood platelets) §Oxygen travels through the body by binding to hemoglobin in red blood cells §An increase in blood viscosity results in resistance to flow Intrinsic Conduction System §Cells of Intrinsic conduction system (ICS) generate their own electrical impulses §Sinoatrial node (SA node) - the pacemaker – it generates electrical impulses the fastest and sets the rhythm for the rest of ICS §Atrioventricular node (AV node) §AV bundle §Bundle branches §Purkinje fibers (subendocardial conducting network) – contractions of the ventricles Diagram Description automatically generated https://www.facebook.com/photo/?fbid=497597494434803&set=pcb.497598781101341 Intrinsic Conduction System §Cells of Intrinsic conduction system (ICS) generate their own electrical impulses §Sinoatrial node (SA node) - the pacemaker – it generates electrical impulses the fastest and sets the rhythm for the rest of ICS; heavily controlled §Atrioventricular node (AV node) §AV bundle §Bundle branches §Purkinje fibers (subendocardial conducting network) – contractions of the ventricles Diagram Description automatically generated https://www.facebook.com/photo/?fbid=497597494434803&set=pcb.497598781101341 https://www.youtube.com/watch?v=sysTSvey4Ow&ab_channel=AnatomyHero https://www.frontiersin.org/articles/10.3389/fphys.2020.00170/full Intrinsic Conduction System A pair of black and yellow shoes Description automatically generated with medium confidence Electrocardiogram (ECG) §Printout shows the heart's electrical activity – can be used to monitor cardiac changes §The P wave – atrial depolarization §The QRS complex – ventricular depolarization and atrial repolarization §ST segment – plateau of action potential, ventricles pump blood §The T wave – ventricular repolarization (diastole) https://www.youtube.com/watch?v=RYZ4daFwMa8&ab_channel=AlilaMedicalMedia https://www.youtube.com/watch?v=v7Q9BrNfIpQ&ab_channel=AlilaMedicalMedia Q – depolarization of the interventricular septum R – depolarization of the main mass of the ventricles S – depolarization at the base of the heart KEY POINTS – Cardiovascular system Vascular system §Arteries §Arterioles §Capillaries §Venules §Veins Carry blood away from the heart Carry blood back to the heart Pulmonary VEINS carry oxygenated blood from the lungs to the heart Pulmonary ARTERIES carry blood with lower oxygen levels to the lungs Vascular system §Arteries §Arterioles §Capillaries §Venules §Veins Vascular system §Arteries §Arterioles §Capillaries §Venules §Veins Vascular system §Arteries §Arterioles §Capillaries §Venules §Veins Vascular system §Arteries §Arterioles §Capillaries §Venules §Veins Blood distribution §Matched to overall metabolic demands §Autoregulation—arterioles within organs or tissues dilate or constrict in response to the local chemical environment §Extrinsic neural control—sympathetic nerves within walls of vessels are stimulated causing vessels to constrict §Determined by the balance between mean arterial pressure and total peripheral resistance Blood Flow Increases with Training §Increased capillarization of trained muscles (higher capillary-to-fiber ratio) §Greater opening of existing capillaries in trained muscles §More effective blood redistribution—blood goes where it is needed §Blood volume increases Blood Volume and Training §Endurance training, especially intense training, increases blood volume §Blood volume increases due primarily to an increase in plasma volume (increases in ADH, aldosterone, and plasma proteins cause more fluid to be retained in the blood) §Red blood cell volume increases, but increase in plasma volume is higher; thus, hematocrit decreases §Blood viscosity decreases, thus improving circulation and enhancing oxygen delivery §Changes in plasma volume are highly correlated with changes in SV and VO2max. Blood and Plasma Volume and Training Cardiovascular Adaptations to Training •Left ventricle size and wall thickness increase •Resting, submaximal, and maximal stroke volume increases •Maximal heart rate stays the same or decreases •Cardiac output is better distributed to active muscles and maximal cardiac output increases •Blood volume increases, as does red cell volume, but to a lesser extent •Resting blood pressure does not change or decreases slightly, while blood pressure during submaximal exercise decreases Respiratory system Respiratory regulation during exercise Respiration •Respiration - delivery of oxygen to and removal of carbon dioxide from the tissue •External respiration—ventilation and exchange of gases in the lung •Pulmonary ventilation – movement of air into and out of the lungs—inspiration and expiration •Pulmonary diffusion – exchange of oxygen and carbon dioxide between the lungs and blood •Internal respiration—exchange of gases at the tissue level (between blood and tissues) • External respiration Rest Inspiration Expiration The diaphragm contracts to pull downwards and chest muscles contract to pull open the chest The diaphragm and the chest muscles relax allowing the lungs to spring back to normal relaxed size – this pushes the air out What muscles help us with breathing? Hypotonic environment Pulmonary ventilation §Nasal cavity – lined by cells that release mucus §Mucus – sticky and salty, contains lysozymes §Nasal hair covered in mucus catch large particles, dust, pollen etc. §Paranasal sinuses – help the air to circulate to get warm and moist §Air flow § - As you breathe in the air goes to the nasal cavity Filled with mucus Lysozymes – help fight bacteria Pulmonary ventilation Diagram Description automatically generated §Lungs' lobes §Trachea and the first three generations of bronchi use cartilage rings for support §Then the bronchi narrow down to bronchioles §No cartilage §15-20 generations The air goes into your lungs Branch out https://www.youtube.com/watch?v=0fVoz4V75_E&ab_channel=Osmosis Respiration Diagram Description automatically generated https://www.youtube.com/watch?v=0fVoz4V75_E&ab_channel=Osmosis Pulmonary ventilation §Terminal bronchioles §Respiratory bronchioles §Alveoli – about 500 000 000 in the lungs §Alveolar duct – the destination of the inhaled air §Pneumocytes §Type I §Type II - surfactant § Diagram Description automatically generated https://www.youtube.com/watch?v=0fVoz4V75_E&ab_channel=Osmosis Pulmonary diffusion Diagram Description automatically generated § §BLOOD-GAS barrier: pneumocytes, endothelial cells and basement membrane (proteins) §Deoxygenated blood arrives via pulmonary arteries §Replenishes blood's oxygen supply that has been depleted for oxidative energy production §Carbon dioxide is removed and breathed out §Oxygenated blood via pulmonary veins – to the heart – to the body What happens in the Alveoli? Deoxygenated blood comes and meets the alveoli – gases can exchange DIFFUSION – partial pressure helps diffusion https://www.youtube.com/watch?v=0fVoz4V75_E&ab_channel=Osmosis Did you know? §Differences in the partial pressures of gases in the alveoli and in the blood create a pressure gradient across the respiratory membrane. This difference in pressures leads to diffusion of gases across the respiratory membrane. The greater the pressure gradient, the more rapidly oxygen diffuses across it. https://www.youtube.com/watch?v=0fVoz4V75_E&ab_channel=Osmosis Gases – partial pressure and exchange §Atmospheric air is a mixture of gases – each with its own partial pressure contributes to the total atmospheric pressure §Alveolar air differs from atmospheric air §The gas exchange occurs between the alveolar air and the blood in capillaries by diffusion – the flow down their concentration gradient or partial pressure gradient §The composition of alveolar air is closely monitored §Gas exchange depends on: §The magnitude of partial pressure gradient (influenced also by altitude) §Solubility (nitrogen is plentiful in the air but does not diffuse into the blood) §Thickness of the pulmonary membrane PV=nRT Nitrogen, carbon dioxide, oxygen… Https://www.youtube.com/watch?v=6qnSsV2syUE&ab_channel=AlilaMedicalMedia PO2 AND PCO2 IN BLOOD Partial Pressures of Respiratory Gases at Sea Level Total 100.00 760.0 760 760 706 0 H2O 0.00 0.0 47 47 47 0 O2 20.93 159.1 105 100 40 60 CO2 0.03 0.2 40 40 46 6 N2 79.04 600.7 568 573 573 0 Partial pressure (mmHg) % in Dry Alveolar Arterial Venous Diffusion Gas dry air air air blood blood gradient KEY POINTS – Pulmonary diffusion §Pulmonary diffusion is the process by which gases are exchanged across the respiratory membrane in the alveoli to the blood and vice versa §The amount of gas exchange depends on the partial pressure of each gas, its solubility, and temperature §Gases diffuse along a pressure gradient, moving from an area of higher pressure to lower pressure §Oxygen diffusion capacity increases as you move from rest to exercise §The pressure gradient for CO2 exchange is less than for O2 exchange, but carbon dioxide’s diffusion coefficient is 20 times greater than that of oxygen’s, so CO2 crosses the membrane easily https://www.youtube.com/watch?v=6qnSsV2syUE&ab_channel=AlilaMedicalMedia Oxygen Transport §Hemoglobin concentration largely determines the oxygen-carrying capacity of blood (>98% of oxygen transported) § §Increased H+ (acidity) and temperature of a muscle allows more oxygen to be unloaded there § §Training affects oxygen transport in muscle Carbon Dioxide Transport §Dissolved in blood plasma (7% to 10%) § §As bicarbonate ions resulting from the dissociation of carbonic acid (60% to 70%) § §Bound to hemoglobin (carbaminohemoglobin) (20% to 33%) § Factors of Oxygen Uptake and Delivery §Oxygen content of blood §Amount of blood flow §Local conditions within the muscle § KEY POINTS – External an Internal Respiration §Oxygen is largely transported in the blood bound to hemoglobin and small amounts are transported dissolved in the blood plasma §Hemoglobin saturation decreases when PO2 or pH decreases, or if temperature increases. These factors increase oxygen unloading in a tissue that needs it §Hemoglobin is usually 98% saturated with oxygen which is higher than what our bodies require, so the blood's oxygen-carrying capacity seldom limits performance §Carbon dioxide is transported in the blood as bicarbonate ion, in blood plasma or bound to hemoglobin §The difference in the oxygen content of arterial and mixed venous blood—reflects the amount of oxygen taken up by the tissues §Carbon dioxide exchange at the tissues is similar to oxygen exchange except that it leaves the muscles and enters the blood to be transported to the lungs for clearance Breathing frequency (BF) Breathing frequency is the number of breaths taken within a set amount of minute: § BF rest = 16 (breaths per minute) (10 in endurance) BF (light exercise) = 20-30 BF (moderate exercise) = 30-40 BF (heavy exercise) = 50-60 § Tidal volume (VT) Tidal volume (l) is the amount of air inspired or expired during normal quiet respiration. VT rest = 0,5 l (1 l in endurance) VT (light exercise) = 1-1,5 l VT (moderate exercise) = 1,5-2 l VT (heavy exercise) = 2-3 l Pulmonary ventilation Ventilation (VE) is the product of tidal volume (TV) and breathing frequency (f): VE rest = 8 l VE (light exercise) = 40 l VE (moderate exercise) = 80 l VE (heavy exercise) = 120l (180l in endurance) Ventilatory Response to Exercise Breathing Terminology Dyspnea = shortness of breath Hypervetilation = increase in ventilation that exceeds the metabolic need for oxygen. Voluntary hyperventilation, as is often done before underwater swimming, reduces the ventilatory drive by increasing blood pH Ventilatory Equivalent for Oxygen §The ratio between VE and VO2 in a given time frame §Indicates breathing economy §At rest—VE/VO2 = 23 to 28 L of air breathed per L VO2 per minute §At max exercise—VE/VO2 = 30 L of air per L VO2 per minute §Generally VE/VO2 remains relatively constant over a wide range of exercise levels Ventilatory Breakpoint §The point during intense exercise at which ventilation increases disproportionately to the oxygen consumption §When work rate exceeds 55% to 70% VO2max, oxygen delivery can no longer match the energy requirements so energy must be derived from anaerobic glycolysis §Anaerobic glycolysis increases lactate levels, which increase CO2 levels (buffering), triggering a respiratory response and increased ventilation Anaerobic Threshold §The point during intense exercise at which metabolism becomes increasingly more anaerobic §Reflects the lactate threshold under most conditions, though the relationship is not always exact §An increase in VE/VO2 without an concomitant increase in the ventilatory equivalent for carbon dioxide (VE/VCO2) Diagram Description automatically generated Anaerobic Threshold Pulmonary Ventilation §The respiratory centres in the brain stem set the rate and depth of breathing §Chemoreceptors respond to increases in CO2 and H+ concentrations or to decreases in blood oxygen levels by increasing respiration §Ventilation increases at the initiation of exercise due to inspiratory stimulation from muscle activity. As exercise progresses, increase in muscle temperature and chemical changes in the arterial blood further increase ventilation § Pulmonary Ventilation §During mild, steady-state exercise, ventilation parallels oxygen uptake §The ventilatory breakpoint is the point at which ventilation increases disproportionately to the increase in oxygen consumption §Anaerobic threshold is identified as the point at which VE/VO2 shows a sudden increase, while VE/VCO2 stays stable. It generally reflects lactate threshold § § Respiratory Limitations to Performance §Respiratory muscles may use up to 11% of total oxygen consumed during heavy exercise and seem to be more resistant to fatigue during long-term activity than muscles of the extremities §Pulmonary ventilation is usually not a limiting factor for performance, even during maximal effort, though it can limit performance in highly trained people §Airway resistance and gas diffusion usually do not limit performance in normal healthy individuals, but abnormal or obstructive respiratory disorders can limit performance § KEY POINTS – Respiratory Adaptations to Training §Pulmonary ventilation increases during maximal effort after training; you can improve performance by training the inspiratory muscles §Pulmonary diffusion increases at maximal work rates §The a-vO2 diff increases with training due to more oxygen being extracted by tissues §The respiratory system is seldom a limiter of endurance performance §All the major adaptations of the respiratory system to training are most apparent during maximal exercise VO2 Adaptations to Training Oxygen consumption (VO2) is §unaltered or slightly increased at rest §unaltered or slighted decreased at submaximal rates of work §increased at maximal exertion (VO2max—increases range from 0% to 93%) Factors Affecting VO2max Level of conditioning—the greater the level of conditioning the lower the response to training Heredity—accounts for slightly less than 50% of the variation as well as an individual’s response to training Age—decreases with age are associated with decreases in activity levels as well as decreases in physiological function Sex—lower in women than men (20% to 25% lower in untrained women; 10% lower in highly trained women) Specificity of training—the closer training is to the sport to be performed, the greater the improvement and performance in that sport Diagram Description automatically generated Vital Capacity §Vital capacity is the maximum amount of air that can be forcefully expired after a maximum inspiration VC females = 3-4 l VC males = 4-5.5 l §From the pulmonary function test the vital capacity testing is the most frequently used. It could be performed „slowly“ (VC) and/or as fast and forced as possible (forced vital capacity, FVC) Vital Capacity Calcultae your predicted value of the vital capacity: Males: Predict. VC (ml) = [27.63 – (0.112 x age (yrs)] x height (cm) Females: Predict. VC (ml) = [21.78 – (0.101 x age (yrs)] x height (cm) Compare your measured values with the predicted values and express them as a percentage of the predicted values Vital Capacity Calcultae your predicted value of the vital capacity: Males: Predict. VC (ml) = [27.63 – (0.112 x age (yrs)] x height (cm) Females: Predict. VC (ml) = [21.78 – (0.101 x age (yrs)] x height (cm) Compare your measured values with the predicted values and express them as a percentage of the predicted values BTPS All the pulmonary volumes should be standardiesd, i.e. converted from actual conditions (ATPS) to the BTPS conditions (Body Temperature and atmospheric Pressure completly Saturated with water vapour at body temperature). BTPS for Czech Republic is 1.09 Thank You!