THER EX: Exam I

Question 0

Endurance

Answer 0

= Ability to perform work for long period
– Resistance to fatigue

Cardiovascular vs. muscular endurance ~

• • Exercise intensity (or power generated)
    
    • • CV = low to moderate
    • • Muscular = high
• • Type of energy system used

Question 1

Fitness

Answer 1

= Ability to perform physical work

Different ways to define:

1) Cardiorespiratory function
2) Muscle strength and endurance
3) Musculoskeletal flexibility
4) Body composition

NOTE: Aerobic or cardiovascular fitness level rated from results of by submaximal or maximal testing

Question 2

Energy systems

Answer 2

= Metabolic systems involving a series of biochemical reactions that result in the formation of ATP

• • ATP releases inorganic phosphate to become ADP
  • • Breaking bond releases ENERGY
  • • ADP + Pi = ATP

(1) Phosphagen or ATP-PC (anaerobic)
(2) Anaerobic glycolytic

(3) Aerobic oxidative
- - Aerobic glycolysis
- - Krebs cycle
- - Electron transport chain

Question 3

Phosphagen (ATP-PC) system

Answer 3

= Phosphocreatine (P-C) breaks into P + C + energy
– Energy combines with ADP and P to form ATP

Characteristics:

• • Immediately available (outside mitochondria)
• • Maximal power (high intensity) (e.g., shot put)
• • No oxygen required
• • Small maximal capacity (limited by supply of PC in muscle)

Used for:

• • Initiation of any type of activity (first 20 seconds) until other systems activated
• • Intermediary throughout long term activity (short duration)

NOTE: “Capacity” refers to the concentration or substrates or enzymes needed for the production of energy by a given system (e.g., glucose, phosphocreatine, aerobic enzymes, ATPase)

Question 4

Anaerobic glycolytic system

Answer 4

= Glucose converted to lactic acid and ATP (energy)

Characteristics:

• • No oxygen required
• • Quick availability (outside mitochondria and few steps)
• • Intermediate maximal power (e.g., 400 m sprint)
• • Limited capacity because of lactic acid buildup
  • • Lowers pH, which halts enzymatic activity needed for conversion of glucose
  • • Ability to remove lactic acid is limiting factor
• • Poor efficiency (only 2 mol ATP per mol glucose)
  • • High amount of heat produced (~70%)

Used for:

• • Relatively high intensity (e.g., sprint)
• • 30-90 seconds of exercise (main source)

Question 5

Aerobic oxidative system

Answer 5

= Aerobic glycolysis to Krebs cycle to electron transport system (ETS)

Characteristics:

• • Oxygen required (to remove H+ ions)
• • KC and ETS inside mitochondria
• • High maximal capacity
• • Small maximal power (low intensity)
• • Very efficient (36 mol ATP / mol glucose)
  • • Less heat produced than anaerobic glycolysis (56%)
• • Slow to initiate/maintain supply
• • Can use fat (beta oxidation) & protein as energy source (lasts longer)
  • • Only at low intensities (even slower process)

Question 6

Lactate thresholds (untrained vs. trained)

Answer 6

= Exercise intensity at which lactic acid starts to accumulate in the blood
– Lactate produced (via anaerobic glycolysis) faster than it can be removed
– Sudden increase in lactic acid related to intensity of exercise
Factors causing lactate accumulation:
– Low tissue O2
– Reliance on glycolysis
– Activation of fast-twitch fibers (high force production)
– Reduced lactate removal

Untrained:

• • At ~50% VO2max ability to generate ATP aerobically is exceeded by demand
  • • Goes back to anaerobic process at higher levels of intensity
  • • Aerobic system not fast enough for high intensity (energy demand > rate of supply)
  • • Cannot maintain higher intensity as long as trained person because of lactic acid build up
• • Decreasing intensity allows switch back to aerobic (lower demand)

Trained:

• • At ~75% VO2max ability to generate ATP aerobically exceeded by demand
  • • Able to perform a higher level of intensity aerobically

Question 7

Factors affecting energy production (rate and duration)

Answer 7

(1) Concentration of enzymes and substrates
- - “Capacity” of system) (e.g., glycogen, PC, fat mobilizing enzymes)

(2) Temperature
- - PE converted to KE + heat
- - Aerobic more efficient than anaerobic (56 vs. 73% heat produced)
- - Enzymes function only in narrow temperature range
- - Increased heat places demand on circulatory system (to dissipate)
- - At too high temperatures energy production stops
- - Switch to aerobic production reduces heat increase (more efficient)
- - Increases work capacity

(3) pH (normal 7.34-7.36)
- - Metabolic processes stop <6.9 or >7.8

Question 8

Specificity principle

Answer 8

= Specific systems respond to specific training stimuli
– Demands or stresses on a specific system lead to adaptations

• • Relates to training for function or sport
• • Mode of exercise should be selected most appropriate for goals of patient

Question 9

Measurement of energy expenditure

Answer 9

(1) Direct calorimetry = human calorimeter to measure heat production as function of energy expenditure
- - 1 kcal = energy to heat 1 kg of water 1 degree C
- - Expensive and involved (only 2 in country)

(2) Indirect calorimetry = correlate amount of oxygen consumed to energy expenditure or work rate
- - 1 L oxygen ~ 5 kcal
- - Open circuit spirometry = measures volume, O2, and CO2 of expired air during exercise test
- - Used to compute amount of O2 consumed
- - Provides accurate estimate of energy expended

Question 10

Metabolic equivalent

Answer 10

= Resting oxygen consumption per kg per minute (3.5 ml/kg/min)

Activity intensity ~ METs:

• • Light = < 3 METs
• • Moderate = 4-6 METs
• • Heavy = 6-8 METs

NOTE: Estimates of activity intensity for “average” individuals

• • Should not be used for individualized exercise prescription
• • Large differences among individuals in exercise capacity
  • • Untrained person may have a maximum capacity of 5 METs, thus 4-6 METs would not be considered “moderate”
• • Elite athlete with maximum capacity of 15 METs would consider 4-6 METs as being light

Question 11

Maximum oxygen consumption

Answer 11

= Maximum amount of oxygen consumed per minute during maximal aerobic effort
– Performing exercise that involves large muscle groups
= How much work can be done aerobically
– Measured with VO2-max testing or estimated with sub-max testing

Other terms:

• • VO2-max or “peak” VO2
  • • Peak may be more accurate b/c cannot know if max was reached
• • Maximal aerobic capacity
• • Maximal oxygen uptake

Units: ml/min or ml/min/kg

Other criteria:

(1) Lactic acid accumulation in blood
- - Indicates switch from aerobic to anaerobic when capacity exceeded
(2) Respiratory exchange rate (RER) (CO2/O2 of air exhaled) > 1
- - CO2 removed from blood to neutralize/buffer acidity from lactic acid accumulation
(3) Reaching age-predicted max HR (variable and less accurate)

NOTE: As resistance or intensity increase, O2 use increases until aerobic capacity maximum is met, then switch to anaerobic energy system causes plateau and decrease in O2 uptake because lactic acid accumulation (pH drop) halts enzymatic action of aerobic system

Question 12

Factors affecting VO2-max

Answer 12

Two main factors:

(1) O2 delivery to tissues
(2) O2 use by tissues

Depends on:

• Delivery
  
  • • Respiratory intake of O2
  • • O2 binding capacity of blood
  • • Perfusion at lung and body tissues
  • • Cardiac function (e.g., cardiac output)
• Tissue use
  
  • • Oxygen extraction capabilities
  • • Muscular oxidative potential (e.g., slow vs. fast twitch)

(1) Pulmonary
- Lung volume (FVC) = size of lungs
- Maximum voluntary ventilation (MVV) = max volume inhaled/exhaled at fastest RR
- Perfusion of lung tissues = gas exchange at alveoli ~ capillarization and CO of RV

(2) Circulatory
- Perfusion = gas exchange at tissues (e.g., muscles)
- CO of LV
- O2 binding capacity

(3) Metabolic
- O2 extraction
- Muscles oxidative potential

Question 13

Fick equation

Answer 13

VO2 = CO x a-vO2 difference
= HR x SV x a-vO2 difference

Normal values:
Resting:
HR 45 (athlete) - 70 (untrained) bpm
SV 80-90 ml (elite athlete >100 ml)
a-vO2 difference 40-50 ml (20-25% extraction) (regardless of training)
– Saturated blood = 200 ml/l
VO2 3.5 ml/kg/min (1 MET) (regardless of training)

Maximum:
HR: 75-85%
SV: 90-100 ml (elite athlete >150 ml)
– Training may increase by 10-15%
a-vO2 difference 140-160 ml (70-80% extraction)
– Trained person has higher max extraction
VO2: 30 (untrained) - 50 (fit normal) - 80 (elite) ml/kg/min

Question 14

Steady state (rate)

Answer 14

= Oxygen uptake meets oxygen demand

• • Energy production primarily based on aerobic energy system
• • Minimal lactic acid accumulation (aerobic)
• • Requires sufficient duration for aerobic system to start producing ATP (>90 seconds)
• • Must reach steady state before measuring energy cost of given activity

NOTE: Fit person more efficient at producing ATP via aerobic system, reaches steady state sooner, and thus has lower oxygen debt

Question 15

Oxygen deficit

Answer 15

= Oxygen used during exercise to break down lactic acid and dissipate heat

• • Oxygen NOT used for energy production
• • Due to anaerobic energy production
• • Generated in early stages of exercise before aerobic system produces ATP
  • • Before reaching steady state
• • Greater for less fit person performing same work
  • • Takes longer to reach steady state
• • Greater for higher intensity exercise
  • • Greater anaerobic contribution
• • Longer recovery time required for high oxygen debt
  • • To restore system to equilibrium O2 levels

Question 16

Fick equation components response to exercise

Answer 16

HR: Linear increase with workload
VO2: Linear increase with workload until plateau/decrease at max
– Plateau at max because O2 demand > O2 use = switch to anaerobic energy production
– Switch to anaerobic causes lactic acid accumulation
– Acidic environment halts enzymatic activity needed for aerobic production
SV: Gradual increase to 150% resting at 50-60% workload then plateau/decrease at max
– Decrease near max due to:
– Large increase in HR reduces time heart is in diastole, reducing filling time and EDV/SV
– Long duration exercise causes decreased blood volume due to sweating (decreases EDV)
– Exercising in excess heat can cause reduced SV
a-vO2 difference: Increases from 20-25% at rest to 70-75% at max

Question 17

Criteria for determining peak VO2

Answer 17

(1) Lactic acid accumulation in blood
- - Switch to anaerobic energy system when O2 demand > O2 supply
(2) Respiratory exchange rate (RER)
- - Normally CO2 = O2 expired
- - As pH drops due to lactic acid, CO2 concentration of blood is reduced to neutralize acidity
- - More CO2 expired
- - RER = CO2/O2 expired > 1
(3) Reach age-predicted maximum HR (220 - age)

Question 18

BMI calculation and classes

Answer 18

= (weight in kg)/(height in m x height in m)

< 18.5 = underweight
18.5-25 = normal
25-30 = overweight
> 30 = obese

Question 19

Purposes of fitness testing

Answer 19

(1) Educate patients about fitness status relative to age- and gender-specific norms
(2) Provide data for the development of exercise program prescriptions
(3) Collect baseline and follow up data to evaluate progress of exercise program participants
(4) Motivate participants by establishing fitness goals
(5) Stratify cardiovascular risk

Question 20

Pre-fitness testing components

Answer 20

(1) PT exam and evaluation

(2) Health screening (risk factors or symptoms)
- - Questionnaire to assess readiness for activity (e.g., PAR or AHA/ACSM Q)
- - Signs or symptoms of cardiopulmonary disease
- - CAD risk factors
- - Comprehensive health and activity questionnaire

(3) Risk stratification (low, moderate, or high)
(4) Medical exam and supervision requirements (based on risk classification)

Question 21

Fitness testing risk stratification

Answer 21

Low:

• • No signs and symptoms or diagnosis of disease (asymptomatic)
• • < 2 CVD risk factors
  • • Can safely pursue physical activity or exercise program w/o medical exam and clearance
  • • No med exam or supervision needed for low/vigorous intensity ex or submax/max testing

Moderate:

• • No signs and symptoms or diagnosis of disease (asymptomatic)
• • > or = 2 CVD risk factors
  • • Can safely engage in LOW/MOD intensity physical activities w/o med exam and clearance
  • • No med exam or supervision needed for low intensity ex or submax testing
  • • Recommended medical exam and exercise test before doing vigorous intensity exercise
  • • Med exam and supervision recommended for vigorous intensity ex or max testing

High:

• • Diagnosed disease OR
• • > or = 1 signs and symptoms of CV, P, or M disease
  • • Requires medical exam and clearance before starting physical activity of ANY intensity
  • • Med exam and supervision recommended for LOW/VIG intensity ex or submax/max testing

Question 22

Fitness test components

Answer 22

Test order:

(1) Resting measurements (e.g., BP, HR)
(2) Blood draws
(3) Body composition
(4) Cardiorespiratory endurance
(5) Muscular fitness
(6) Flexibility

Question 23

Assumptions of submaximal testing

Answer 23

(1) Age-predicted maximal heart rate (AAMHR) = actual maximum heart rate (e.g., 220 - age)
(2) Linear relation between HR/VO2 and work load

(3) Steady state HR achieved at each work load
- - Steady state = oxygen uptake meets oxygen demands
- - Ensures work is done aerobically (minimal anaerobic input)
- - Requires duration sufficient for aerobic system produce ATP (e.g., 2-3 min per stage)

(4) Mechanical efficiency is the same among individuals (i.e., cyclist vs. runner)
(5) Individual is not on medications that alter HR response (e.g., beta blockers)

Question 24

Fitness test termination criteria

Answer 24

(1) Onset of angina or angina-like symptoms

(2) Abnormal BP response
- - Drop in systolic BP (>10 mmHg) despite increase in workload
- - Excessive rise in BP (systolic > 250 mmHg or diastolic > 115 mmHg)
(3) Respiratory problems (e.g., shortness of breath, wheezing)

(4) Circulation problems (e.g., leg cramps, claudication)

(5) Signs of poor perfusion (i.e., blood supply to tissues)
- - Lightheadedness
- - Confusion
- - Ataxia = lack of muscle coordination
- - Pallor
- - Cyanosis
- - Nausea
- - Cold and clammy skin
(6) HR does not increase despite increase in intensity

(7) Change in heart rhythm (measured on ECG)
(8) Subject requests to stop
(9) Manifestations of severe fatigue (physical or verbal)
(10) Failure of testing equipment

Question 25

Signs and symptoms of CVD, PD, or MD

Answer 25

(1) Pain or discomfort in chest, neck, jaw, arms, or other areas affected by ischemia (angina)
(2) Shortness of breath (dyspnea) at rest or with mild exertion
(3) Dyspnea when lying or recumbent relieved when sitting upright
(4) Dizziness or syncope (fainting)
(5) Ankle edema
(6) Palpitations or tachycardia
(7) Intermittent claudication
(8) Known heart murmur

Question 26

CVD risk factors

Answer 26

(1) Age (>45 y men and >55 y women)
(2) Family history (MI, coronary revascularization, or sudden death)
(3) Smoking (current or recent)
(4) Obesity (BMI > 30)
(5) Sedentary lifestyle
(6) Dislipidemia (high LDL or low HDL) (total > 200 ml/dl)
(7) Hypertension (>140/90)
(8) Prediabetes (blood glucose 100-125 mg/dl)

"WATCH Glucose"
Weight
Activity
Tobacco
Hypertension
Glucose level

Question 27

Quantifying energy expenditure

Answer 27

Methods:

• • Measure amount of O2 consumed
  • • Direct calorimetry = human calorimeter measures heat production/energy expenditure
  • • Indirect calorimetry = measures oxygen use ~ energy expenditure ~ work performed
    • • Open circuit spirometry = measures O2/CO2 content of expired air ~ energy expenditure

Units:

• • Kcal = amount of energy needs to raise 1 kg of water 1 degrees C
  • • Can be expressed in oxygen equivalents (5 kcal = 1 L O2 consumed)
• • MET = 3.5 mL oxygen consumed per kg of body weight per min (3.5 ml/kg per minute)

Question 28

Acute cardiac responses to exercise

Answer 28

(1) Increased HR
- - Anticipatory (e.g., stress and excitement)
- - Linear increase w/ workload up to 4 x resting HR
- - Increase due to sympathetic input

(2) Increased SV
- - Linear increase up to 150% resting at 50-60% max workload
- - Increase due to sympathetic input to heart (contractility) and vessels (vasoconstriction)
- - Plateau and then decrease due to decreased EDV
- - Less filling time as HR increases (early stages)
- - Decreased blood volume with sweating (prolonged exercise)

(3) Increased CO (= HR x SV)

Question 29

Acute coronary responses to exercise

Answer 29

= Increased myocardial O2 demand

• • Coronary artery vasodilation critical
• • Increased coronary blood flow
• • Two other factors affecting O2 supply to heart do not increase:
  • • Driving pressure (e.g., diastolic) stays constant
    • • Peripheral vasodilation = systemic vasoconstriction)
    • • Coronary arteries can only fill during diastole due to squeezed heart during systole
  • • Length of diastole decreases relative to systole (2/3 cycle at rest) and overall (faster HR)
    • • Less time for coronary artery filling

NOTE: Insufficient vasodilation (e.g., brittle, inelastic) or stenosis of coronary arteries causes ischemia of heart tissue (limits work capacity in CAD patients)

Question 30

Acute systemic circulatory responses to exercise

Answer 30

• • Systemic vasoconstriction (sympathetic input)
• • Peripheral vasodilation (localized)
  • • Shunts blood from nonworking (e.g., digestion) to working tissues (e.g., muscles, lungs)
  • • Increases O2 delivery to working tissues
• • Increased body temperature
  • • Vasodilation in skin to dissipate heat via evaporation and convection
  • • Temperature regulation in hypothalamus
  • • Increased circulatory stress in hot and humid conditions

Question 31

Acute respiratory responses to exercise

Answer 31

• • Increased respiratory rate (= 12-18 to 35-45 (60-70 elite) breaths per minute)
• • Increased tidal volume (= 0.5-2.0 L air per breath)
  • • Increased minute volume (= 6-100-200 L air per minute)

NOTE: Respiratory factors rarely limiting to maximum aerobic capacity in healthy individuals, but may be limiting for pulmonary patients or elite athletes

Question 32

Acute BP responses to exercise

Answer 32

• • Increased systolic BP
  • • Systemic vasoconstriction (sympathetic input)
  • • Increased CO (HR x SV) (more blood per unit time increases pressure on vessels)
• • No change in diastolic BP
  • • Peripheral resistance offsets systemic vasoconstriction

NOTE: Cool down period after exercise critical to prevent sudden drop in BP, dizziness, and/or fainting (especially in patients on vasodilation meds), as takes time for vessels in legs to return to normal tone and muscle pump no longer supporting venous return to heart; monitor BP until it stabilizes (may have hypotensive response post-exercise)

Question 33

Acute blood responses to exercise

Answer 33

• • Perspiration has opposing effects:
  • • Increased blood viscosity = increase resistance to flow = increase BP
  • • Decreased blood volume = decrease BP

Question 34

Acute metabolic response to exercise

Answer 34

• • Increased oxygen uptake (VO2 = HR x SV x a-vO2-diff)
  • • 3.5 ml/kg/min at rest up to 70 ml/kg/min at max exercise
• • Increased oxygen extraction by tissues (~25 to 75% of mixed venous blood)

NOTE: Oxygen use by tissues at cellular level limiting factor for maximum aerobic capacity

- - Mechanisms that increase O2 delivery do not increase VO2 max IF
  - - Cellular ability to use O2 efficiently limits ATP production (aerobic capacity)

Question 35

Adaptations to aerobic training (chronic responses)

Answer 35

(1) Cardiac:
- - Heart muscle hypertrophy (bigger and stronger)
- - Larger SV
- - Bradychardia at rest (with larger SV need lower HR for same CO)
(2) Circulatory:
- - Increased capillary density of tissues (e.g., muscles, lungs)
- - Increased oxygen extraction by tissues
- - Increased a-vO2-diff (70-85%)
(3) Decreased resting systolic and diastolic BP
- - increased capillary density decreases peripheral resistance
- - More powerful vasodilation decreases peripheral resistance
(4) Blood and fluid:
- - Increased total blood volume
- - More efficient sweating (more efficient heat dissipation)
(5) Metabolic:
- - Increase mitochondria = increase ATP production efficiency
- - Increased aerobic enzymes = more efficient O2 use = higher anaerobic threshold
- - Increased glycogen storage = increased endurance
- - Increased fat oxidation ability = increased glycogen sparing
(6) Body composition:
- - Increased lean mass (muscle) and decreased body fat
(7) Other:
- - May improve cholesterol and triglycerides (variable)
- - Decrease depression, increase mentation, and increase well-being

Question 36

Factors affecting training response

Answer 36

• • Initial fitness level
  • • Sets training stimulus threshold (stress level needed to cause adaptations)
• • Intensity, duration, and frequency of training

NOTE: Typically 6-8 weeks to see significant improvements in aerobic capacity in untrained individuals

Question 37

FITT table categories and values

Answer 37

Categories:

• • Poor = Sedentary (no habitual physical activity)
• • Poor-Fair = Minimal physical activity
• • Fair-Average = Sporadic physical activity
• • Average-Good = Habitual physical activity (regular moderate to vigorous intensity)
• • Good-Excellent = High amounts of habitual activity

HRR/VO2R:

• • Poor = 30-45%
• • Poor-Average = 40-50%
• • Fair-Average = 55-70%
• • Average-Good = 65-80%
• • Good-Excellent = 70-85%

HR-max (NOT VO2-max)

• • Poor = 57-67%
• • Poor-Fair = 64-74%
• • Fair-Average = 74-84%
• • Average-Good = 80-91%
• • Good-Excellent = 84-94%

NOTE: VO2R is preferred (most accurate) method (recommended by ACSM)

Question 38

Typical values at rest and maximum:

• HR
• SV
• a-vO2
• EF
• VO2

Answer 38

Elite -- Trained -- Untrained -- Heart failure (30 y/o male)
Rest:
-- HR: 45 - 55 - 70 - 90 bpm
-- SV: 136 - 110 - 87 - 68 ml
-- a-vO2: 20-25% = 40-50 ml/l (for all)
-- EF: 72 - 69 - 58 - 43 %
-- VO2: 3.5 ml/kg/min (for all)

Max:

• • HR: 190 - 190 - 190 - 175 bpm
• • SV: 184 - 137 - 84 - 77 ml
• • a-vO2: 80 - 75 - 70 - 60 % = 160 - 150 - 140 - 110 ml/l
• • EF: 92 - 81 - 62 - 45 %
• • VO2: 81 - 56 - 35 - 21 ml/kg/min

General:
SV = 80-90 ml (at rest)
– Increases with exercise and training (10-15%)
EF = 60-80% (at rest)
– < 60% indicates heart problem
EDV = 150-200 ml
– Changes little with exercise (slight increase)

No change with training:

• • Max HR
• • Resting CO (HR x SV) (higher SV = lower HR in trained)
• • Resting oxygen extraction (20-25%)
• • Resting VO2 (3.5 ml/kg/min)