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EDU2EXP Exercise & Performance
Cardiovascular and pulmonary systems
EDU2EXP Exercise & Performance
Mid Session Quiz -25%
• Next week• Will be on WebCT assessments• From 9 am 25/8/08 5 pm 29/8/08• Multiple choice and matching• Practice test (question types) up now, practice (content) on
companion website for text.• Covers all lecture, lab, text and reading materials from
weeks 1-5• Time limit = ½ hour• Grades will be released automatically• Contact me if tech problems
EDU2EXP Exercise & Performance
Today
• Cardiovascular– System review– Acute adaptations to exercise– Chronic adaptations to exercise
• Pulmonary– System review– Acute adaptations to exercise– Chronic adaptations to exercise
EDU2EXP Exercise & Performance
Major Cardiovascular Functions
Major Cardiovascular Functions
• Delivers oxygen to active tissues • Aerates blood returned to the lungs • Transports heat, a byproduct of cellular
metabolism, from the body’s core to the skin
• Delivers fuel nutrients to active tissues • Transports hormones, the body’s
chemical messengers
EDU2EXP Exercise & Performance
CV system
• Consists of;– Blood ~ 5L or 8% body mass
• 55% plasma• 45% formed elements (99%RBC, 1%WBC)
– Heart- pump– Arteries- High pressure transport– Capillaries- Exchange vessels– Veins- Low pressure transport
EDU2EXP Exercise & Performance
EDU2EXP Exercise & Performance
EDU2EXP Exercise & Performance
Peripheral VasculaturePeripheral Vasculature• Arteries
– Provides the high-pressure tubing that conducts oxygenated blood to the tissues
• Capillaries– Site of gas, nutrient,
and waste exchange• Veins
– Provides a large systemic blood reservoir and conducts deoxygenated blood back to the heart
EDU2EXP Exercise & Performance
EDU2EXP Exercise & Performance
Blood Pressure Blood Pressure
• Systolic blood pressure– Highest arterial pressure measured after left
ventricular contraction (systole)– e.g., 120 mm Hg
• Diastolic blood pressure– Lowest arterial pressure measured during
left ventricular relaxation (diastole)– e.g., 80 mm Hg
EDU2EXP Exercise & Performance
EDU2EXP Exercise & Performance
EDU2EXP Exercise & Performance
Heart Rate Regulation Heart Rate Regulation
• Cardiac muscle possesses intrinsic rhythmicity
• Without external stimuli, the adult heart would beat at about 100 bpm
EDU2EXP Exercise & Performance
Regulation of HRRegulation of HR
• Sympathetic influence – Catecholamine (NE/E)– Results in tachycardia
• Parasympathetic influence– Acetylcholine – Results in bradycardia
• Cortical influence– Anticipatory heart rate
EDU2EXP Exercise & Performance
CV system during exercise
Acute Adaptations
Chronic adaptations
EDU2EXP Exercise & Performance
Heart rate
• At rest- 60-80 bpm– Trained athletes lower (28-40 bpm)
• Pre exercise- anticipatory response– Sympathetic nervous system release N/E and
ephedrine
• Increases during exercise to steady state
EDU2EXP Exercise & Performance
Cardiovascular DynamicsCardiovascular Dynamics• Q = HR × SV (Fick
Equation)– Q: cardiac output– HR: heart rate– SV: stroke volume
EDU2EXP Exercise & Performance
Cardiac Output• At Rest
– Q = 5 L p/Min• Trained RHR = 50 bpm, SV = 71• Untrained RHR = 70 bpm, SV = 100
• During Exercise– Untrained- Q = 22 000 mL p/min, MHR = 195
» SV av 113 ml blood p/beat
– Trained- Q= 35 000 ml p/min, MHR = 195» SV av 179 ml blood p/beat
Q = HR × SV
EDU2EXP Exercise & Performance
Increases in Stroke Volume
• Increases in response to exercise
• Is ability to fill ventricles, particularly left ventricle
• And more forceful contraction to pump blood out
• Training adaptations– left ventricle hypertrophy– Increased blood volume– Reduced resistance to
blood flow
EDU2EXP Exercise & Performance
Training Adaptations: Heart
• Eccentric hypertrophy – Slight thickening in left
ventricle walls– Increases left ventricular
cavity size
Therefore increases stroke
volume
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Cardiac output distribution
EDU2EXP Exercise & Performance
Oxygen transport
• When arterial blood is saturated with oxygen :• 1 litre blood carries 200 ml oxygen • During exercise
– Q = 22L p /min• = 4.4L oxygen per minute
• At rest– Q = 5L p/ min
• = 1 L oxygen per minute• 250 ml required at rest• Remainder- oxygen reserves
EDU2EXP Exercise & Performance
Stroke Volume and Cardiac Output
• Exercise increases stroke volume during rest and exercise
• Slight decrease heart rate
• Increase in cardiac output comes from increased stroke volume
EDU2EXP Exercise & Performance
Heart Rate
• Elite athletes have a lower heart rate relative to training intensity than sedentary people
EDU2EXP Exercise & Performance
Saltin, 1969
Endurance athletes
Sedentary college BEFORE 55 day aerobic training program
Sedentary college AFTER
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Total Blood Volume
* Plasma volume
-4 training sessions can increase plasma volume by 20%
*Increased RBC
- Number of RBC increases, but due to increase in Plasma volume, concentration stays the same
EDU2EXP Exercise & Performance
Blood Pressure
• Aerobic exercise reduces systolic and diastolic BP at rest and during exercise
• Particularly systolic– Caused by decrease in catecholamines
• Another reason for exercise to be prescribed for those with hypertension
• Resistance training not recommended due to acute high BP it causes
EDU2EXP Exercise & Performance
Oxygen Extraction
• Training increases quantity of O2 that can be extracted during exercise
EDU2EXP Exercise & Performance
Chronic Adaptations to Exercise- Chapter 10
Cardiovascular adaptations to training are extremely important for improving endurance exercise performance, and preventing cardiovascular diseases.
The more important of these adaptations are, Size of heart ventricular volumes total blood volume
- plasma volume - red cell mass
systolic and diastolic blood pressures maximal stroke volume maximal cardiac output extraction of oxygen
EDU2EXP Exercise & Performance
Factors Affecting Chronic adaptations
• Initial CV fitness• Training:
– Frequency- 3 x p/week• Only slightly higher gains for 4 or 5 times p/week
– Intensity• Most critical• Minimum is 130/ 140 bpm = (av) 50-55% Vo2 max/ 70% HR max • Higher = better
– Time • Or duration- 30 min is minimum
– Type• Specificity
EDU2EXP Exercise & Performance
Pulmonary System
EDU2EXP Exercise & Performance
EDU2EXP Exercise & Performance
Pulmonary Structure and Function
Pulmonary Structure and Function
• The ventilatory system– Supplies oxygen required in metabolism – Eliminates carbon dioxide produced in
metabolism – Regulates hydrogen ion concentration [H+]
to maintain acid-base balance
EDU2EXP Exercise & Performance
Breathing• At rest– Air in Trachea-
humidified and brought to body temperature
divides into 2 branches lungs
– Lungs hold 4-6 litres of ambient air- huge surface area
– 300 million alveoli– 250 ml oxygen in and
200 ml Carbon dioxide out each minute
EDU2EXP Exercise & Performance
Inspiration• Ribs rise• Diaphragm contracts
(flattens)
Moves downward (10cm)• Thoracic volume• Air in lungs expands • Pressure
to 5 mm Hg below atmospheric pressure
• Difference between outside air and lungs = air is sucked in until pressure inside and out is the same
EDU2EXP Exercise & Performance
Expiration
• Ribs move back down• Diaphragm relaxes (rises)• Thoracic volume• Pressure • Difference between outside air and lungs = air
is pushed out until pressure inside and out is the same
EDU2EXP Exercise & Performance
EDU2EXP Exercise & Performance
Pulmonary system during exercise
EDU2EXP Exercise & Performance
Lung VolumesLung Volumes
• Static lung volume tests– Evaluate the dimensional component for
air movement within the pulmonary tract, and impose no time limitation on the subject
• Dynamic lung volume tests– Evaluate the power component of
pulmonary performance during different phases of the ventilatory excursion
EDU2EXP Exercise & Performance
Spirometry
• Static and Dynamic lung volumes are measured using a spirometer
EDU2EXP Exercise & Performance
Static Lung Volumes
Page 146 of text
EDU2EXP Exercise & Performance
Dynamic lung volumes
• Depend on Volume of air moved
and the
• Speed of air movement
FEV/FVC ratio
MVV
EDU2EXP Exercise & Performance
FEV/FVC Ratio
• Forced Expiratory Volume
• Forced Vital Capacity
• Ratio tells us the speed at which air can be forced out of lungs
• Normal = 85% FVC can be expired in 1 second.
EDU2EXP Exercise & Performance
Maximal Voluntary Ventilation
• Breath as hard and fast as you can for 15 seconds
• Multiply by 4• And you have Maximal Voluntary
Ventilation• MVV-
– Males:140-180 Litres– Females: 80-120 Litres– Elite athletes up to 240 Litres
EDU2EXP Exercise & Performance
Minute Ventilation
At Rest• 12 breaths per minute• Tidal volume = 0.5L per
breath• = 6 Litres of air breathed
p/minDuring Exercise• 50 breaths p/ minute• Tidal Volume = 2 L per
breath• = 100L p/min
EDU2EXP Exercise & Performance
Alveolar VentilationAlveolar Ventilation
• Minute ventilation is just total amount of air
• Alveolar ventilation refers to the portion of minute ventilation that mixes with the air in the alveolar chambers
• Minute ventilation minus anatomical dead space (150-200 ml)- the air that is in the trachea, bronchi etc
EDU2EXP Exercise & Performance
Alveolar Ventilation =
Minute ventilation (TV x breathing rate) – dead space
EDU2EXP Exercise & Performance
Gas exchange
EDU2EXP Exercise & Performance
Gas Exchange in the Body Gas Exchange in the Body
• The exchange of gases between the lungs and blood, and their movement at the tissue level, takes place passively by diffusion
EDU2EXP Exercise & Performance
EDU2EXP Exercise & Performance
Oxygen Transport in the Blood Oxygen Transport in the Blood
• Combined with hemoglobin — In loose combination with the iron-protein hemoglobin molecule in the red blood cell
• Each Red Blood Cell contains 250 million hemoglobin molecules
• Each one can bind 4 oxygen molecules
EDU2EXP Exercise & Performance
CO2 Transport in Blood CO2 Transport in Blood
• In physical solution– (~7%) dissolved in the fluid portion of the
blood
• As carbamino compounds – (~20%) in loose combination with amino acid
molecules of blood proteins
• As bicarbonate– (~73%) combines with water to form carbonic
acid
EDU2EXP Exercise & Performance
Regulation of Pulmonary VentilationRegulation of Pulmonary Ventilation
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Regulation at rest: Plasma Pco2 and H+ Concentration
Regulation at rest: Plasma Pco2 and H+ Concentration
• The partial pressure of CO2 provides the most potent respiratory stimulus at rest
• [H+] in the cerebrospinal fluid bathing the central chemoreceptors provides a secondary stimulus driving inspiration
EDU2EXP Exercise & Performance
Ventilatory Regulation During Exercise
Ventilatory Regulation During Exercise
• Chemical control– Po2
– Pco2
– [H+]
• Nonchemical control
• Neurogenic factors– Cortical influence– Peripheral influence
EDU2EXP Exercise & Performance
Ventilation in steady rate exercise
Ventilation in steady rate exercise
• Of oxygen ( V E/ V O2)
– Quantity of air breathed per amount of oxygen consumed
– Remains relatively constant during steady-rate exercise- 25 L air breathed per 1L o2 consumed at 55% Vo2 max
• Of carbon dioxide ( V E/ V CO2)
– Remains relatively constant during steady-rate exercise
EDU2EXP Exercise & Performance
• The point at which pulmonary ventilation increases disproportionately with oxygen uptake during graded exercise
• The excess ventilation relates to the increased CO2 production associated with buffering of lactic acid
Ventilatory ThresholdVentilatory Threshold
EDU2EXP Exercise & Performance
Pulmonary adaptations to Exercise
EDU2EXP Exercise & Performance
EDU2EXP Exercise & Performance
Adaptations to
Maximal exercise
• Minute ventilation increases
• Increased oxygen uptake
EDU2EXP Exercise & Performance
Submaximal Exercise
• Ventilatory muscles stronger
• Ventilatory equivalent for oxygen
( V E/ V O2) reduces indicates breathing efficiency– This leads to
• Reduced fatigue in ventilatory muscles• O2 that would have been used by those muscles
can be used by skeletal muscle.
EDU2EXP Exercise & Performance
Pulmonary Adaptations
• Increased tidal volume
• Decreased breathing frequency
• Increased time between breaths (Increased time for oxygen to get into bloodstream)
• Therefore less oxygen in exhaled air
EDU2EXP Exercise & Performance
Summary
• Need to know– Cardiac and pulmonary Structure and
Function• Veins/arteries/cappilaries• Flow of blood through the heart• Alveoli bronchii etc• Flow of inspired air and pulmonary exchange
– Acute adaptations to exercise– Chronic adaptations to exercise
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