Title: Exercise Physiology
1 Exercise Physiology
- J.M. Cairo, Ph.D.
- LSU Health Sciences Center
- New Orleans, Louisiana
- jcairo_at_lsuhsc.edu
2Somatic Factors Sex and Age Body Dimension Health
Psychic Factors Attitude Motivation
Training Adaptation
- Bioenergetics
- Storage Fuels
- Fuel Intake
- Oxygen Uptake
- Cardiac Output
- Heart Rate
- Stroke Volume
- (A-V)O2 Difference
- Pulmonary Ventilation
Environment Temperature Altitude Inhaled Gases
Nature of Work Intensity Duration Rhythm Technique
Position
Energy Yielding Processes
From Astrand and Rodahl, Textbook of Work
Physiology, New York McGraw-Hill, 1972
Physical Performance Capacity
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8From Richardson, DR, Randall, DC, Speck, DF
Cardiopulmonary System. Madison, CT, Fence
Creek, 1998
9From Wasserman, K., Hansen, J.E., Sue, D.Y.,
Casaburi, R, and Whipp, B.J. Principles of
Exercise Testing and Interpretation, 3rd Edition.
Philadelphia, Lippincott Williams and Wilkins,
1999.
10The Fick Principle
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12RESTING CONDITIONS FOR A TYPICAL HEALTHY ADULT
VO2 250 ml/min Q 5
L/min CaO2 200 ml/L of whole
blood CvO2 150 ml/L of whole
blood CaO2-CvO2 50 ml/L of whole blood
13MAXIMUM EXERCISE RESPONSE FOR A WORLD CLASS
ATHLETE
VO2 5000 ml/min Q 25
L/min CaO2 200 ml/L of whole
blood CvO2 20 ml/L of whole blood CaO2-CvO2
180 ml/L of whole blood
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16Cardiac Output
Heart Rate
Stroke Volume
Preload
Contractility
-
Afterload
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19HRMAX 220 - age (yrs)
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22PRELOAD
Volume of blood in the ventricle at the end of
diastole LVEDV
Venous Return
23Frank-Starling Mechanism
Stroke Volume
LVEDV
24PRELOAD
Volume of blood in the ventricle at the end of
diastole LVEDV
Venous Return
Skeletal Muscle Pump
Venous Tone
Thoraco-abdominal Pump
25Contractility
Stroke Volume
LVEDV
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33Factors influencing the Pulmonary Response to
Exercise
- Ventilation
- Diffusion of Oxygen and Carbon Dioxide Across the
Alveolar-Capillary Membrane - Perfusion
- Ventilation/Perfusion
- O2 and CO2 Transport
- O2 uptake by the tissues
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35Control of Breathing During Exercise
- Immediate Response
- Neural Component
- Central Command
- Learned Response
- Direct Connection from Motor Cortex
- Coordination in Hypothalamus
- Proprioceptors or Mechanoreceptors
From Levitzky, MG Pulmonary Physiology, 5th
Edition. New York, McGraw-Hill, 1999
36Control of Breathing During Exercise
- Response to Moderate Exercise
- Arterial Chemoreceptors
- Metaboreceptors
- Nociceptors
- Cardiac Receptors
- Venous Chemoreceptors
- Temperature Receptors
- Response to Severe Exercise
- Arterial Chemoreceptors
- Central Chemoreceptors
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40Factors Influencing the Maintenance of the
Arterial Oxygen Content (CaO2)
- Increase in Alveolar Ventilation
- Decrease in VD/VT
- Increased Perfusion of the Lungs
- Decrease in Pulmonary Vascular Resistance
- Recruitment and Distension of Pulmonary
Capillaries - Improvement in VA/QC
- Increased Diffusion of O2 and CO2 across the
Alveolar-Capillary Membrane
41Effective Ventilation VD/VT
0.40
VD/VT
0.25
Rest
Max
42Factors Influencing Unloading/Uptake of Oxygen at
the Tissues (?CvO2)
- Shifting of the Oxyhemoglobin Dissociation Curve
to the Right - Increase in Core Temperature
- Increase in CO2 Production
- Increase in H
43Somatic Factors Sex and Age Body Dimension Health
Psychic Factors Attitude Motivation
Training Adaptation
- Bioenergetics
- Storage Fuels
- Fuel Intake
- Oxygen Uptake
- Cardiac Output
- Heart Rate
- Stroke Volume
- (A-V)O2 Difference
- Pulmonary Ventilation
Environment Temperature Altitude Inhaled Gases
Nature of Work Intensity Duration Rhythm Technique
Position
Energy Yielding Processes
Physical Performance Capacity
44MAXIMUM EXERCISE RESPONSE FOR A WORLD CLASS
ATHLETE
VO2 5000 ml/min Q 25
L/min CaO2 200 ml/L of whole
blood CvO2 20 ml/L of whole blood CaO2-CvO2
180 ml/L of whole blood
45MAXIMUM EXERCISE RESULTS FOR A TYPICAL HEALTHY
ADULT
VO2 2500 ml/min Q 15 L/min CaO2 200
ml/L of whole blood CvO2 33 ml/L of whole
blood CaO2-CvO2 167 ml/L whole blood
46Principles of Physical Training
- Overload
- Specificity
- Reversibility
47Training for Improved Aerobic Endurance
- Type of Exercise
- Intensity
- Duration
- Frequency
48Anaerobic Threshold
- The anaerobic threshold is defined as the level
of exercise VO2 above which aerobic energy is
supplemented by anaerobic mechanisms and is
reflected by an increase in lactate and
lactate/pyruvate ratio in skeletal muscle and
arterial blood. - See Wasserman, K., Hansen, J.E., Sue, D.Y.,
Casaburi, R, and Whipp, B.J. Principles of
ExerciseTesting and Interpretation, 3rd Edition.
Philadelphia, Lippincott Williams and Wilkins,
1999.
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50Karvonen Formula for Prescribing Exercise Heart
Rate
- HREx HRRest 0.60 (HRMax HRRest)
51Detraining and VO2 MAX
- Decreased maximum attainable cardiac output and
arteriovenous O2 difference - Initial (12-14 days)
- Decrease due to decreased stroke volume
- Decreased plasma volume
- Prolonged (3 weeks 12 weeks)
- Attenuation of arteriovenous O2 difference
changes - Decreased muscle mitochondrial density
52Effects of Endurance Training on Skeletal Muscle
Morphology
- Capillary Density
- Myoglobin
- Mitochondria
53Effects of Endurance Training on Skeletal Muscle
Metabolism
- Mobilization of FFA
- Transport of FFA from Cytoplasm to the
Mitochondria - Mitochondrial Oxidation of FFA
- Beta-oxidation
- Lactate Removal
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56Effect of Conditioning on Heart Rate Response
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59Effects of Chronic Physical Activity on Aerobic
Function
Resting Values Effect
Oxygen Consumption Unchanged
Heart Rate Decreased
Systolic Blood Pressure Unchanged-Decreased
Diastolic Blood Pressure Unchanged-Decreased
Rate-Pressure Product Decreased
60Effects of Chronic Physical Activity on Aerobic
Function
Submaximal Values Effect Effect
Oxygen Consumption Oxygen Consumption Unchanged-Decreased
Cardiac Output Cardiac Output Unchanged
Heart Rate Heart Rate Decreased
Stroke Volume Stroke Volume Increased
Systolic Blood Pressure Systolic Blood Pressure Decreased
Rate-Pressure Product Rate-Pressure Product Decreased
Minute Ventilation Minute Ventilation Decreased
61Effects of Chronic Physical Activity on Aerobic
Function
Maximal Values Effect
Oxygen Consumption Increased
Cardiac Output Increased
Heart Rate Unchanged-Decreased
Stroke Volume Increased
Arteriovenous O2 Difference Increased
Systolic Blood Pressure Unchanged
Rate-Pressure Product Unchanged
Ejection Fraction Increased
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64Exercise Testing Strategies
- Incremental versus steady state tests
- Modes of exercise
- Treadmills
- Bruce versus Balke Protocol
- Cycles
- Ramp Protocol
65Noninvasive Measurements
- Respiratory
- Vt
- Fb
- VE
- FIO2
- FEO2
- FECO2
- Pulse oximetry
- PtcO2, PtcCO2
66Noninvasive Measurements
- Cardiovascular
- Heart rate
- Arterial blood pressure
- Electrocardiogram
- Modified chest leads
- 12 lead ECG
67Normal ECG Changes During Exercise
- P wave increases in height
- R wave decreases in height
- J point becomes depressed
- ST segment becomes sharply up sloping
- QT interval shortens
- T wave decreases in height
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69Reasons for Stopping a Test
- ECG criteria
- Severe ST segment depression (gt3 mm)
- ST segment elevation (gt1 mm in non-Q wave lead)
- Frequent ventricular extrasystole
- Onset of ventricular tachycardia
- New atrial fibrillation or supraventricular
tachycardia - Development of new bundle branch block (if the
test is primarily to detect underlying coronary
disease) - New second or third degree heart block
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73Invasive Measurements
- Arterial blood gases
- pHa, PaCO2, PaO2
- Blood lactate levels
- Pulmonary artery catheterization
- Pulmonary vascular pressures (PA, PAWP)
- Mixed venous blood gases (pHv, PvCO2, PvO2)
74Derived Variables
- Peak VO2 versus VO2Max
- Respiratory
- VD/VT
- VD/VT PaCO2- PECO2/PaCO2
- P(A-a)O2
- P(a-et)CO2
- Breathing reserve
- Breathing reserve MVV VE max
75Derived Variables
- Cardiovascular
- Heart rate reserve
- HR reserve HRmax (predicted) HRmax (achieved)
- O2 pulse
- O2 pulse VO2/HR SV X (CaO2-CvO2)
76Reasons for Stopping a Test
- Symptoms and signs
- Patient requests stopping because of severe
fatigue - Severe chest pain, dyspnea, or dizziness
- Fall in systolic blood pressure (gt20 mmHg)
- Rise in blood pressure (gt300 mmHg, diastolic gt
130 mmHg) - Ataxia
77Case 20020240
- Resting Data
- Age 75 yrs
- Sex Male
- VC 3.5L (100)
- IC 2.3L (102)
- TLC 6.0L (110)
- FEV1 3.90L (95)
- FEV1/VC 80
- MVV 100L
- Hct 44
- Exercise Data
- VO2 (Peak) 1.75L (100)
- HRMAX 140 bpm
- SBP 155/84 180/75
- VEMAX 70L/min
- VD/VT 0.35 0.25
- P(A-a)O2 20 torr
- ?AT 1.4L
Patient stopped exercise due to dyspnea
78Case 20000512
- Exercise Data
- VO2 (Peak) 1.55L(58)
- HRMAX 168 bpm
- SBP 150/92 205/120
- VEMAX 48L
- VD/VT 0.40 0.30
- P(A-a)O2 20 torr
- ?AT 1.30L
- Resting Data
- Age 48 yrs
- Sex Male
- VC 4.75L (93)
- IC 3.94L (95)
- TLC 5.90L (98)
- FEV1 3.90L (93)
- FEV1/VC 80
- MVV 90L
Patient stopped exercise due to angina and
presence of multiple PVBs
79Findings Suggesting High Probability of Coronary
Artery Disease
- ST segment depression 2 mm
- Downsloping ST segment depression
- Early positive response within 6 minutes
- Persistence of ST depression for more than 6
minutes into recovery - ST segment depression in 5 or more leads
- Exertional hypotension
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82Case 20011120
- Resting Data
- Age 60 yrs
- Sex Male
- VC 3.75L (80)
- IC 2.75L (70)
- TLC 6.53L (130)
- FEV1 2.80L (65)
- FEV1/VC 60
- MVV 65L
- Exercise Data
- VO2 (Peak) 1.75L (68)
- HRMAX 128 bpm
- SBP 135/88 200/110
- VEMAX 60L/min
- VD/VT 0.40 0.38
- P(A-a)O2 45 torr
- ?AT 1.10L
Patient stopped exercise due to extreme dyspnea
83Case 20011452
- Resting Data
- Age 70 yrs
- Sex Male
- VC 3.65L (78)
- IC 2.28L (72)
- TLC 6.03L (81)
- FEV1 2.20L (6)
- FEV1/VC 60
- MVV 95L
- DLCO 10.8 (35)
- Exercise Data
- VO2 (Peak) 1.32L (65)
- HRMAX 152 bpm
- SBP 175/86 227/90
- VEMAX 90L/min
- VD/VT 0.45 0.48
- P(A-a)O2 45/68 torr
- PaO2 64/52 torr
- ?AT 0.95L
Patient stopped exercise due to extreme dyspnea
84Case 2001367
- Resting Data
- Age 60 yrs
- Sex Male
- VC 1.75L (40)
- IC 1.55L (42)
- TLC 8.03L (120)
- FEV1 0.54L (15)
- FEV1/VC 30
- MVV 35L
- DLCO 19 (59)
- Exercise Data
- VO2 (Peak) 1.75L (68)
- HRMAX 128 bpm
- SBP 135/88 200/110
- VEMAX 60L/min
- VD/VT 0.40 0.38
- P(A-a)O2 45 torr
- ?AT 1.10L
Patient stopped exercise due to extreme dyspnea
85Temperature Regulation
86Definitions
- Core Temperature
- Measured as oral, aural, or rectal temperature
- Temperature of deep tissues of the body
- Remains relatively constant (?1ºF or ?0.6ºC)
unless a person develops a febrile condition - Nude person can maintain core temperature even
when exposed to temperatures as low as 55ºF or as
high as 130ºF in dry air - Skin Temperature
- Rises and falls with the temperature of the
surroundings
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89REGULATION OF BODY TEMPERATURE
90Heat Production
- Laws of Thermodynamics
- Heat is a by-product of metabolism
- Basal metabolic rate of all cells of the body
- Effect of muscular activity on metabolic rate
- Effect of endocrinology on metabolic rate (i.e.,
thyroxin, growth hormone, testosterone) - Effect of autonomic nervous system on metabolic
rate
91Heat Loss
- How fast is heat transferred from deep tissues to
the skin - How rapidly is heat transferred from the skin to
the surrounding environment
92How Fast Is Heat Transferred From Deep Tissues to
Skin
- Insulation Systems
- Skin and subcutaneous tissue (i.e., fat)
- Blood Flow
- Cutaneous circulation
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95How Fast Is Heat Loss From the Skin to the
Surrounding Environment
- Radiation
- Conduction
- Evaporation
96Definitions
- Radiation
- Loss of heat by infrared heat rays (5-20?m or
10-20X wavelength of visible light) - Conduction
- Loss of heat from the body to a solid object
- Evaporation
- Loss of heat from the body through water vapor to
the surrounding atmosphere - Convection
- Effects of changes in the external environment
(e.g., wind and water)
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98Wind Chill Factor
- Effect of wind on skin temperature temperature
of calm air that would produce equivalent cooling
of exposed skin - Cooling effect of air convection equals the
square root of the wind velocity - For example, air temperature feels twice as cold
at a wind velocity of 4 mph than if the wind
velocity is 1 mph
99ºF 35.74 0.6215T - 35.75V(100.16)
0.4275V(100.16)
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102Regulation of Body Temperature Role of the
Hypothalamus
- Anterior Hypothalamus Preoptic Area
- Heat-sensitive neurons
- Demonstrate a 10-fold increase in firing rate
when there is a 10C increase in body temperature
resulting in profuse sweating and cutaneous
vasodilation - Cold-sensitive neurons
- Increase in firing rate to a decrease in body
temperature resulting in cutaneous
vasoconstriction and inhibition of sweat
production
103Temperature RegulationSkin and Deep Tissue
Receptors
- Although the skin contains both cold and warmth
sensory receptors, there are far more cold
receptors than warmth receptors (10 times more
cold than warmth) - Stimulation of these cold receptors will result
in shivering, inhibition of sweating, and
promotion of cutaneous vasoconstriction
104Temperature RegulationSkin and Deep Tissue
Receptors
- Deep tissue receptors are found in spinal cord,
in the abdominal viscera, and in the great veins
in the upper abdomen and thorax - Although these receptors are exposed to core body
temperature rather than skin temperature, they
function like the skin receptors in that they are
concerned with preventing hypothermia
105Hormonal Control of Temperature
- Chemical Thermogenesis
- Ability of norepinephrine and epinephrine to
uncouple oxidative phosphorylation - Brown fat
- Thyrotropin-releasing hormone ?
Thyroid-stimulating hormone ? Thyroxine - Stimulated by cooling of the anterior
hypothalamic-preoptic area - Requires several weeks of exposure to cold to
cause hypertrophy of the thyroid gland -
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108Abnormalities of Body Temperature Regulation
- Fever
- Effect of pyrogens
- Brain lesions
- Heatstroke
- Frostbite
- Malignant Hyperthermia