Note
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Lectures Weeks 5-10
Key Notes on Exercise Physiology (Training)
1. VO2 Max Overview
Formula: VO2 max = HR max × SV max × (a-vO2) max
Factors affecting VO2 max:
Increased Stroke Volume: Plasma volume ↑ 11% → Stroke volume ↑ 10%
Arteriovenous O2 Difference:
↑ Muscle blood flow (↓ SNS vasoconstriction)
↑ Capillary density & mitochondrial number → Improved O2 extraction
Graph Trend: VO2 max increases with training, then decreases rapidly with detraining (~8% in 12 days, ~20% in 84 days).
2. Endurance Training Adaptations
Mitochondrial Adaptations:
Training increases mitochondrial number → Requires less ADP to stimulate ATP production.
Effect: Faster oxygen uptake → Smaller O2 deficit → Less reliance on anaerobic metabolism.
Lactate Production & Blood pH:
Training reduces lactate accumulation:
↑ Mitochondria → Less pyruvate accumulation
↑ NADH shuttle → Less lactate formation
LDH enzyme shifts to H4 form → Lower pyruvate-lactate conversion
Graph Trend: Trained individuals show lower blood lactate at the same workload.
Fuel Utilization:
↑ Fat metabolism efficiency due to ↑ mitochondria & capillary density.
Less carbohydrate reliance → Spares glycogen stores.
3. Detraining Effects
VO2 Max Decline:
↓ Stroke volume due to rapid plasma volume loss.
↓ a-vO2 difference due to fewer mitochondria and oxidative enzymes.
Muscle Fiber Shift: Type IIa ↓, Type IIx ↑ (loss of endurance adaptations).
Graph Trend: Mitochondrial content declines rapidly within a few weeks but regains quickly upon retraining.
4. Strength Training & Concurrent Training
Neural & Muscular Adaptations:
Initial Strength Gains: Neural adaptations (motor unit recruitment, coordination).
Long-Term Gains: Muscle hypertrophy (↑ fiber size, myonuclei increase).
Detraining & Retraining:
Strength decreases over 30 weeks, but retraining over 6 weeks restores previous levels.
Concurrent Training Limitations:
Endurance training inhibits hypertrophy via mTOR pathway suppression.
Overtraining risks: CNS fatigue, impaired recovery.
Sample Multiple-Choice Questions
VO2 Max & Cardiovascular Adaptations
Which of the following is the primary factor responsible for an increase in VO2 max after 6 days of endurance training?
A) Increased mitochondrial density
B) Increased blood lactate concentration
C) Increased plasma volume
D) Increased Type IIx muscle fibers
Answer: C) Increased plasma volume
What happens to the arteriovenous O2 difference after endurance training?
A) It decreases due to reduced mitochondrial content
B) It increases due to greater oxygen extraction by muscles
C) It remains unchanged
D) It decreases due to lower blood flow
Answer: B) It increases due to greater oxygen extraction by muscles
Mitochondrial & Metabolic Adaptations
How does endurance training affect oxygen deficit at the onset of exercise?
A) Increases it by delaying mitochondrial ATP production
B) Decreases it by allowing faster VO2 response
C) Has no effect on oxygen deficit
D) Causes greater reliance on anaerobic metabolism
Answer: B) Decreases it by allowing faster VO2 response
Which of the following is NOT a reason for reduced lactate production after endurance training?
A) Increased mitochondrial density
B) Increased pyruvate accumulation
C) Increased NADH shuttling to mitochondria
D) A shift to LDH H4 isoform
Answer: B) Increased pyruvate accumulation
Detraining & Strength Training
What is the primary reason for the rapid decline in VO2 max within the first 12 days of detraining?
A) Loss of mitochondrial density
B) Decrease in stroke volume due to plasma volume loss
C) Decrease in Type IIa fibers
D) Reduced muscle glycogen stores
Answer: B) Decrease in stroke volume due to plasma volume loss
Why does concurrent endurance training impair muscle hypertrophy?
A) It increases protein degradation rates
B) It suppresses mTOR activation required for muscle growth
C) It increases Type IIx fiber conversion
D) It reduces oxidative enzyme activity
Answer: B) It suppresses mTOR activation required for muscle growth
Which of the following training strategies helps maintain strength gains with minimal effort after an initial 12-week training period?
A) Training 3 times per week for another 12 weeks
B) Training 1 time per week for 12 weeks
C) Stopping training altogether
D) Training twice daily for 6 weeks
Answer: B) Training 1 time per week for 12 weeks
Week 7:
Key Notes on Exercise Physiology (Chapters 1-4 of "Exercised")
1. VO2 Max and Detraining Effects
VO2 Max Lab:
Measurement involves treadmill running at 22% grade (12.5° incline).
Rating of Perceived Exertion (RPE) used to assess effort.
Detraining Effects on VO2 Max:
Rapid decline:
↓ 8% in 12 days (mainly due to plasma volume loss).
↓ 20% in 84 days (due to reduced mitochondrial content and oxidative enzymes).
Muscle fiber shift:
↓ Type IIa fibers (fatigue-resistant)
↑ Type IIx fibers (less oxidative capacity)
Graph Trend:
VO2 max declines rapidly in the first weeks of detraining but can recover quickly with retraining.
2. Strength Training and Concurrent Training
Neural vs. Muscular Adaptations:
Early Strength Gains: Due to neural factors (motor unit recruitment).
Later Gains: Due to muscle hypertrophy (myonuclei increase).
Detraining & Retraining Effects:
30 weeks of detraining leads to strength loss.
6 weeks of retraining restores most strength gains.
Minimal training required to maintain strength: 1 session per week.
Concurrent Training Interference:
Endurance training suppresses muscle growth via mTOR inhibition.
Potential interference mechanisms:
Neural limitations
Overtraining
Protein synthesis suppression
3. Energy Expenditure & Respiratory Quotient (RQ)
Measuring Energy Expenditure:
Direct Calorimetry: Measures heat production.
Indirect Calorimetry: Measures O2 consumption and CO2 production.
Respiratory Quotient (RQ) = CO2 produced / O2 consumed
Carbohydrates: RQ = 1.0 (efficient use of oxygen).
Lipids: RQ = 0.71 (more oxygen required for oxidation).
Proteins: RQ = 0.83 (depends on nitrogen excretion).
RQ > 1.0 indicates excess CO2 production (e.g., during hyperventilation or metabolic acidosis).
Graph Trend:
Fat oxidation predominates at lower intensities, while carbohydrate oxidation increases with higher intensities.
4. Human Evolution and Physical Activity
Myth #1: We Evolved to Exercise:
Humans evolved to conserve energy, not to exercise for fun.
Physical activity was necessary for survival (hunting, gathering).
Myth #2: Inactivity is Unnatural:
Rest is biologically necessary to preserve energy.
Hunter-gatherers alternate between high and low activity.
Myth #3: Sitting is Intrinsically Unhealthy:
Sitting itself isn’t harmful; the issue is chronic inactivity.
Health risks include:
Metabolic syndrome (insulin resistance)
Postural imbalances (weak glutes, tight hip flexors)
Cardiovascular disease (lower blood flow)
Myth #4: You Need Exactly Eight Hours of Sleep:
Sleep needs vary by individual.
Hunter-gatherers average 6-7 hours per night but take naps.
5. Catecholamines and Exercise
Plasma Epinephrine & Norepinephrine Response:
Increase with exercise intensity.
Mobilize fuel by:
Stimulating glycogenolysis.
Enhancing lipolysis.
Graph Trend:
Steady increase in epinephrine/norepinephrine as exercise duration and intensity rise.
Sample Multiple-Choice Questions
VO2 Max & Cardiovascular Adaptations
Which of the following is the main reason for an 8% drop in VO2 max after 12 days of detraining?
A) Decrease in capillary density
B) Loss of mitochondria
C) Decrease in plasma volume
D) Increase in Type IIx muscle fibers
Answer: C) Decrease in plasma volume
Which of the following changes occurs after 84 days of detraining?
A) Increased oxidative enzyme activity
B) Decreased maximal a-vO2 difference
C) Increased mitochondrial density
D) Increased Type IIa fibers
Answer: B) Decreased maximal a-vO2 difference
Strength Training & Concurrent Training
What is the primary reason strength gains are maintained with minimal training (once per week)?
A) Myonuclei acquired from training persist for long periods
B) Muscle hypertrophy does not decrease with detraining
C) Endurance training promotes muscle mass retention
D) Muscle fiber type conversion prevents strength loss
Answer: A) Myonuclei acquired from training persist for long periods
Why does endurance training impair muscle hypertrophy?
A) It decreases oxygen transport to muscles
B) It inhibits mTOR, reducing protein synthesis
C) It increases neural drive, decreasing muscle growth
D) It prevents activation of Type IIx muscle fibers
Answer: B) It inhibits mTOR, reducing protein synthesis
Energy Metabolism & Respiratory Quotient (RQ)
What is the primary reason lipids have a lower respiratory quotient (0.71) compared to carbohydrates (1.0)?
A) Lipids require more oxygen for breakdown
B) Lipids store less energy than carbohydrates
C) Lipids generate more ATP per oxygen molecule
D) Lipids produce more CO2 per oxygen molecule
Answer: A) Lipids require more oxygen for breakdown
Which of the following would result in an RQ > 1.0?
A) High-fat diet
B) Prolonged fasting
C) Anaerobic glycolysis and lactate accumulation
D) Low-intensity endurance exercise
Answer: C) Anaerobic glycolysis and lactate accumulation
Evolution & Exercise Myths
What is the primary evolutionary reason humans did not evolve to exercise regularly?
A) Early humans relied primarily on stored energy sources
B) Physical activity was only performed when necessary for survival
C) Exercise was unnecessary due to abundant food sources
D) Resting was viewed as biologically harmful
Answer: B) Physical activity was only performed when necessary for survival
What is a major health consequence of prolonged sitting?
A) Reduced oxygen transport to muscles
B) Increased risk of insulin resistance
C) Increased mitochondrial biogenesis
D) Decreased catecholamine production
Answer: B) Increased risk of insulin resistance
Which of the following is TRUE about sleep needs?
A) All humans need exactly 8 hours of sleep per night
B) Hunter-gatherers averaged 10-12 hours of sleep per night
C) Sleep needs vary among individuals, and naps can compensate for shorter nights
D) Exercise decreases sleep requirement
Answer: C) Sleep needs vary among individuals, and naps can compensate for shorter nights
Week 9:
Key Notes on Exercise Physiology (Walking, Running, and Aging)
1. Walking & Bipedalism
Hadza vs. Westerners:
The Hadza (hunter-gatherers) take more steps per day than the average Western individual.
Westerners have more sedentary lifestyles, which leads to increased health risks.
Advantages of Bipedalism:
Energy efficiency in long-distance travel.
Better thermoregulation (upright posture reduces heat exposure).
Freeing of hands for tool use and carrying objects.
Weight Loss & Walking:
Walking alone does not burn enough calories to cause major weight loss unless combined with dietary changes.
Intensity and duration impact caloric burn.
2. Running & Persistence Hunting
David Carrier’s Hypothesis (1984):
Humans evolved for endurance running to outlast prey (Persistence Hunt).
Unique adaptations include:
Sweating instead of panting for cooling.
Spring-like tendons for energy-efficient movement.
Stable head position to aid in balance.
Running Mechanics:
Speed = Stride Length × Stride Frequency
Scaling:
Larger animals tend to have lower stride frequency but longer stride lengths.
Human hopping or galloping experiments illustrate how body size affects locomotion.
3. Endurance & Aging
The Grandmother Hypothesis:
Suggests older adults helped human survival by providing knowledge and resources.
The Active Grandparent Hypothesis:
Suggests that consistent physical activity in older adults delays aging and promotes longevity.
Senescence & Cellular Damage:
Aging leads to:
Mitochondrial dysfunction
Oxidative stress
Inflammation
Despite similar damage occurring in exercise, training is beneficial due to repair mechanisms.
4. Sarcopenia & Age-Related Strength Loss
Muscular Strength Decline with Age:
Begins after age 50 at a rate of 1-2% per year.
Leads to 40-60% total muscle loss by age 80.
Causes:
Reduced muscle fiber size
Loss of muscle fibers
Reduced neuromuscular activation
Effects of Strength Training on Sarcopenia:
Trained Individuals: Resistance training (2-3x per week) helps maintain muscle mass.
Active Individuals: Walking ~5000 steps/day slows muscle loss.
Sedentary Individuals: Experience the most rapid muscle decline.
5. VO2 Max & Endurance with Age
VO2 Max Decline:
1% decrease per year after 40.
Training slows but does not prevent the decline.
Sprint vs. Endurance Performance with Aging:
Sprint performance declines faster due to loss of fast-twitch muscle fibers.
Endurance performance is better maintained due to preserved exercise economy and lactate threshold.
Graph Trends:
VO2 max steadily declines, but trained individuals maintain higher values than sedentary individuals.
Exercise & Aging Benefits:
Long-term exercise reduces disease risk and preserves function.
20-50 years of consistent training leads to improved aging outcomes.
Sample Multiple-Choice Questions
Walking & Bipedalism
Which of the following is NOT an advantage of bipedalism?
A) Greater energy efficiency in long-distance movement
B) Improved heat dissipation
C) Increased running speed compared to quadrupeds
D) Ability to carry tools and objects
Answer: C) Increased running speed compared to quadrupeds
Compared to the Hadza, Westerners typically:
A) Take more steps per day
B) Have lower rates of sedentary behavior
C) Are more likely to develop diseases linked to inactivity
D) Engage in more natural endurance activity
Answer: C) Are more likely to develop diseases linked to inactivity
Running & Persistence Hunting
What is the key idea behind David Carrier’s 1984 hypothesis on human running?
A) Humans evolved to sprint for short distances
B) Humans developed long-distance running for persistence hunting
C) Humans evolved for efficient climbing rather than running
D) Human running speed is determined solely by leg length
Answer: B) Humans developed long-distance running for persistence hunting
What is the correct formula for running speed?
A) Speed = Stride Length + Stride Frequency
B) Speed = Stride Frequency × Stride Length
C) Speed = Stride Frequency ÷ Stride Length
D) Speed = Stride Length - Stride Frequency
Answer: B) Speed = Stride Frequency × Stride Length
Aging & Muscle Loss
What is the rate of muscle mass loss (sarcopenia) after age 50?
A) 0.5% per year
B) 1-2% per year
C) 5% per year
D) 10% per year
Answer: B) 1-2% per year
Which of the following training strategies is most effective in slowing sarcopenia?
A) Strength training 2-3 times per week
B) Walking 2000 steps per week
C) Sprint training only
D) Performing only stretching exercises
Answer: A) Strength training 2-3 times per week
VO2 Max & Endurance Decline
VO2 max decreases by approximately ______ per year after age 40.
A) 0.5%
B) 1%
C) 3%
D) 5%
Answer: B) 1%
Why does endurance performance decline with age?
A) Decline in exercise economy
B) Reduced lactate threshold
C) Decrease in VO2 max and cardiovascular function
D) Loss of all Type I muscle fibers
Answer: C) Decrease in VO2 max and cardiovascular function
Which of the following is LEAST affected by age-related decline?
A) Sprinting ability
B) Endurance performance
C) Lactate threshold
D) VO2 max
Answer: C) Lactate threshold
How can exercise help mitigate the effects of aging?
A) Completely prevents muscle loss
B) Reverses the effects of VO2 max decline
C) Slows but does not stop the decline in fitness
D) Has no impact on the aging process
Answer: C) Slows but does not stop the decline in fitness
Week 10:
Final Exam Notes – Exercise Physiology
Chapter 11: To Move or Not to Move – How to Make Exercise Happen
Barriers to Exercise:
Lack of time, motivation, enjoyment, or social support.
Perceived difficulty or physical limitations.
Environmental and societal factors (access to facilities, safety concerns).
Making Exercise Fun:
Gamification, social engagement, variety, music, and competition.
Mandatory Exercise?:
Pros: Health benefits, reduced healthcare costs, improved productivity.
Cons: Ethical concerns, personal choice, practicality.
Chapter 12: How Much and What Type of Exercise?
Recommended Exercise Levels:
Adults: 150-300 minutes moderate or 75-150 minutes vigorous aerobic activity + 2+ days resistance training per week.
Children: 60+ minutes of physical activity daily.
Exercise Types & Trade-offs:
Aerobic (Endurance): Improves cardiovascular fitness but may increase stress if excessive.
Resistance Training: Strength, muscle mass, metabolism boost.
Flexibility & Balance: Reduces injury risk, improves mobility.
Chapter 13: Exercise and Disease
Exercise & Immunity
Immunosenescence (Aging & Immune System Decline)
Reduced immune response, increased risk of illness.
Exercise enhances immune function (e.g., increased T cells, lower inflammation).
Open Window Theory:
High-intensity/long-duration exercise temporarily suppresses immune function, increasing infection risk.
Exercise in Extreme Environments:
Cold: No significant increased risk.
Heat: Dehydration and stress can affect immunity.
High Altitude: Temporary immune suppression.
Exercise & Specific Diseases
Sample Multiple-Choice Questions
Basic Concept Questions
Which of the following is NOT a main barrier to exercise? A) Lack of motivation
B) Time constraints
C) Genetic predisposition
D) Lack of enjoyment
Answer: C) Genetic predispositionWhat is the recommended amount of weekly exercise for adults? A) 75 minutes moderate, 2 days resistance
B) 150-300 minutes moderate, 2+ days resistance
C) 200 minutes vigorous, no resistance training required
D) 60 minutes of physical activity daily
Answer: B) 150-300 minutes moderate, 2+ days resistance
Graph Trend Interpretation
A graph showing immune function post-exercise likely follows which trend? A) Immediate increase with intense exercise, then rapid drop
B) A steady decline over time with regular exercise
C) A dip immediately post-exercise but long-term enhancement with moderate training
D) No change regardless of exercise intensity
Answer: C) A dip immediately post-exercise but long-term enhancement with moderate trainingWhich graph would best represent the "Open Window Theory"? A) A steady increase in immunity with higher intensity exercise
B) A sudden drop in immune function after prolonged high-intensity training, followed by gradual recovery
C) No change in immune function post-exercise
D) Immediate immune function improvement after all types of exercise
Answer: B) A sudden drop in immune function after prolonged high-intensity training, followed by gradual recovery
Application Questions
A 65-year-old individual wants to strengthen their immune system through exercise. What would be the best recommendation? A) High-intensity interval training (HIIT) every day
B) Moderate aerobic and resistance training regularly
C) Avoid exercise to prevent illness risk
D) Only focus on flexibility and balance training
Answer: B) Moderate aerobic and resistance training regularlyWhich of the following is most accurate regarding exercise and mental health? A) Exercise has no proven effect on mood disorders
B) Only resistance training improves mental health
C) Aerobic exercise increases endorphins, reducing depression symptoms
D) High-intensity exercise worsens anxiety
Answer: C) Aerobic exercise increases endorphins, reducing depression symptoms