Final Exam Exercise Physiology

What are the three key principles of training?

Overload, specificity, and reversibility

Which principle refers to the fact that an organ system or tissue must be exercised at a level beyond which it is accustomed to achieve a training adaptation?

Overload

What are the three exercise training variables that constitute overload?

Intensity, duration, and frequency

Which principle is corollary to the overload principle?

The principle of reversibility

Which principle refers to the fact that the fitness gains achieved by exercising at an overload are quickly lost when training is stopped and the overload is removed?

The principle of reversibility

Which principle refers to the fact that exercise training is specific to the muscles involved in that activity, the fiber types recruited, the principal energy system involved (aerobic vs. anaerobic), the velocity of contraction, and the type of muscle contraction?

The principle of specificity

What refers to the types of adaptations occurring in muscle as a result of training?

Specificity

What is the measure of the maximal capacity of the body to transport and use oxygen during dynamic exercise with large muscle groups?

Maximal oxygen uptake (also called maximal aerobic power or VO₂ max)

What plays a giant role in VO2 max and biological responses to exercise training?

Genetics

Following short-duration training, all of the training-induced improvement in VO2 max is due to increases in what?

Cardiac output.

Short durations of endurance do not significantly increase the a-vo2 difference.

Following both short and long duration endurance training, the exercise-induced increase in cardiac output is entirely due to increases in what?

Stroke volume

Because heart rate either remains constant or slightly decreases

A key factor that is responsible for increasing stroke volume is an increase of what?

End Diastolic Volume (EDV)

What increases for the left ventricle's stretch and contractility through Frank-Starling to also increase?

End diastolic volume (EDV)

Endurance training not only increases stroke volume during maximal exercise but also increases stroke volume during what?

Rest

Endurance training increases stretch of myocardium (higher EDV)

What refers to the strength of the cardiac muscle contraction when the EDV, afterload, and heart rate remain constant?

Contractility

What refers to the peripheral resistance against which the ventricle is contracting as it tries to push blood into the aorta?

Afterload

The increased capacity of the muscle to extract O₂ after training is primarily due to the increase in what?

Capillary density

With an increase in mitochondrial volume being of secondary importance

What accommodates the increase in muscle blood flow during exercise, decreases the diffusion distance to the mitochondria, and slows the rate of blood flow to allow more time for oxygen diffusion from the capillary to the muscle fiber?

Enlarged capillary density

What increases to result in an increase in end-diastolic volume and an increase in plasma volume?

Preload

A decrease in the arteriolar constriction in the trained muscles increases maximal muscle arterial blood pressure. How does it affect afterload?

Decreases afterload

The training-induced increase in the a-vO2 difference is due to what?

An increase in capillary density of the trained muscles, which is needed to accept the increase in maximal muscle blood flow.

What allows for a slow red blood cell transit time through the muscle, providing enough time for oxygen diffusion from the capillary into the muscle fiber?

Greater capillary density

A shift in what muscle fiber does endurance training result in?

Fast-to-slow muscle fiber type

What increases mechanical efficiency and therefore can potentially improve endurance performance?

Fast-to-slow shift in myosin isoforms

True or false? There is 1 subpopulation of mitochondria exist in skeletal muscle

False. There are two subpopulations of mitochondria that exist in skeletal muscle. One population rests beneath the sarcolemma, and a second and larger group is dispersed around the contractile proteins

What are the three energy systems?

phosphocreatine, anaerobic glycolysis, oxidative phosphorylation

What are the time domains for each bioenergetics pathway?

Phosphocreatine 5-30 seconds

Anaerobic glycolysis 30-3 minutes

Oxidative phosphorylation 3 minutes to several hours

Which produces ATP FASTEST, which one LONGEST?

Fastest —-→ Phosphocreatine system

Longest —-→ Oxidative phosphorylation

What Macronutrient Fuels which?

What macronutrient fuels which?

Phosphocreatine —→ carbs

Glycolysis —→ carbs

Oxidative Phosphorylation —→ carbs, fats or proteins

What is the general relationship between fat/CHO burning and
intensity?

1. Fat and carbohydrate (CHO) are the main fuels for aerobic metabolism during exercise in a well-fed person.

2. Fat is the dominant energy source at low aerobic power outputs (< 40% VO2max) and provides ~50% of the required energy during moderate intensity exercise

RER, respiratory exchange ratio is what?

is the ratio between the volume of CO2 being produced by the body and the amount of O2 being consumed

Do we try and maintain or use blood glucose as a major fuel source?

Yes

Where does lactate come from and what regulates the formation?

product of pyruvate metabolism under anaerobic conditions

Wait, wait, wait....what
the HECK is Lactate
anyways?

Lactate is created
from pyruvate when
energy needs to be
made FAST (or in
lower oxygen
environments)

Walk me through how a nervous system signal is sent

For the nervous system to function, neurons must be able to send and receive signals. These signals are possible because each neuron has a charged cellular membrane (a voltage difference between the inside and the outside), and the charge of this membrane can change in response to neurotransmitter molecules released from other neurons and environmental stimuli. To understand how neurons communicate, one must first understand the basis of the baseline or ‘resting’ membrane charge.

How do we signal for muscle to contract?

When the nervous system signal reaches the neuromuscular junction a chemical message is released by the motor neuron. The chemical message, a neurotransmitter called acetylcholine, binds to receptors on the outside of the muscle fiber. That starts a chemical reaction within the muscle.

How does muscle contract?

depolarization of the muscle cell down the T-tubules, ca2+ gated feet then sense the depolarization, SR releases calcium to then bind to troponin, tropomyosin will then shift in order for the myosin head to then grab the actin, ADP and Pi drop off creating the power stroke, Myosin head re-cock, ATP is the hydrolyzed and broken down into ADP and Pi re-cock reset reload

What happens if we block calcium release?

H+ will then bind to troponin causing a muscle contraction to not occur

What is the ‘size principle’?

Henneman’s size principle describes relationships between properties of motor neurons and the muscle fibers they innervate and thus control, which together are called motor units.

Starting with the inferior vena cava, track a molecule of hemoglobin all the way through our body and back to the starting point.

• The hemoglobin molecule is inside a red blood cell (RBC).

• The inferior vena cava delivers deoxygenated blood from the lower body to the right atrium of the heart.

• Blood flows through the tricuspid valve into the right ventricle.

• Upon contraction, the right ventricle pumps blood through the pulmonary valve into the pulmonary arteries, leading to the lungs.

• In the lungs, gas exchange occurs:

  • The hemoglobin releases carbon dioxide.

  • It binds with oxygen (O₂), becoming oxyhemoglobin.

• Oxygen-rich blood travels via the pulmonary veins into the left atrium.

• Blood passes through the bicuspid (mitral) valve into the left ventricle.

• The left ventricle contracts, pushing blood through the aortic valve into the aorta.

• Blood is distributed via arteries to all body tissues.

• In body tissues (like muscles or organs), hemoglobin releases oxygen to cells.

• It picks up carbon dioxide (CO₂), a waste product of cellular respiration.

• Deoxygenated blood returns via systemic veins to the inferior vena cava, completing the loop.

What is the function of hemoglobin?

• Oxygen Transport – Each hemoglobin molecule can bind up to four oxygen molecules (O₂), making it essential for delivering oxygen efficiently throughout the body.

• Carbon Dioxide Transport – Hemoglobin helps transport about 20–25% of carbon dioxide (CO₂) from tissues back to the lungs, though most CO₂ travels dissolved in plasma or as bicarbonate.

• Buffering Blood pH – Hemoglobin also acts as a buffer, helping to maintain blood pH by binding to hydrogen ions.

contraction phase: systole

relaxation phase: diastole

What is an EKG? Draw one and label the curves.

• P wave – Atrial depolarization (atria contract)

• QRS complex – Ventricular depolarization (ventricles contract)

• T wave – Ventricular repolarization (ventricles relax)

How does an EKG tell us what the heart is doing?

• P Wave – Shows atrial depolarization (electrical impulse causing the atria to contract).

• QRS Complex – Represents ventricular depolarization (ventricles contract), and is the most prominent part of the EKG.

• T Wave – Indicates ventricular repolarization (ventricles reset and prepare for the next beat).

What is Cardiac Output? What is the equation for it?

Cardiac Output (CO)=Heart Rate (HR)×Stroke Volume (SV)

Cardiac Output (CO) is the amount of blood the heart pumps in one minute.

• Heart Rate (HR) = number of beats per minute (bpm)

• Stroke Volume (SV) = amount of blood pumped by one ventricle in one beat (mL/beat)

How can we manipulate Q?

• Increase Heart Rate (HR)

• Decrease Heart Rate

• Increase Stroke Volume (SV)

• Decrease Stroke Volume

Why do we breathe?

We breathe to supply oxygen to our body's cells and to remove carbon dioxide, a waste product of metabolism.

How do we breathe?

We breathe through a process called pulmonary ventilation, which involves the movement of air into and out of the lungs. It happens in two main phases: inhalation (inspiration) and exhalation (expiration).

How do we transport O2 and CO2?

We transport oxygen (O₂) and carbon dioxide (CO₂) through the bloodstream, using red blood cells, plasma, and specialized molecules like hemoglobin.

What is the oxyhemoglobin dissociate curve?

The oxyhemoglobin dissociation curve is a graph that shows the relationship between the partial pressure of oxygen (PaO₂) and the percent saturation of hemoglobin with oxygen (SaO₂).

What does the oxyhemoglobin dissociation curve help us understand?

The oxyhemoglobin dissociation curve helps us understand how readily hemoglobin picks up and releases oxygen under different physiological conditions. It's crucial for understanding oxygen delivery to tissues and oxygen loading in the lungs.

What does the ventilatory response to exercise look like?

The ventilatory response to exercise describes how your breathing rate and depth change to meet the increased oxygen demands and carbon dioxide production during physical activity.

Movement of air from environment to lungs is called ‘______’

‘bulk flow’

What are the primary sources of H+?

Carbonic Acid (H₂CO₃), Lactate + H+, ATP Hydrolysis

Why do we not like high H+ in our bodies?

We don’t like high levels of H⁺ (hydrogen ions) in our bodies because it makes our internal environment too acidic, which can seriously disrupt normal cellular function.

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⚠ Here’s why high H⁺ (low pH) is harmful:

1. Enzyme Dysfunction

2. Disrupted Cellular Processes

3. Reduced Oxygen Binding (Bohr Effect)

4. Acidosis

5. Calcium Imbalance

How do we eliminate/buffer acid levels?

• Bicarbonate Buffer System (Primary in Blood)

• H⁺ binds to bicarbonate to form carbonic acid → converted to CO₂ and water, then CO₂ is exhaled.

• Protein Buffers

• Proteins (like hemoglobin) bind excess H⁺, especially inside red blood cells.

• Phosphate Buffers

• Help in urine and intracellular fluid.

What are the primary adaptations to ET?

1. Mitochondrial biogenesis

2. capillary density

What are the primary adaptations to RT?

1. hypertrophy

2. bone density

3. neural tuning

What does fasting and fed states have in similar with ET & RT?

Fasting and ET emphasize efficiency, endurance, and fat use, while the fed state and RT promote growth, recovery, and glucose use.

What is the central energy sensor in the body?

AMPK

What stimulates mTOR?

Stimulus	Effect on mTOR
Resistance training	↑ Strong activation
Leucine (protein)	↑ Direct activation
Insulin (carbs)	↑ Supportive
IGF-1 / GH	↑ Growth signal
Fasting / low energy	↓ Inhibits mTOR

What does mTOR stimulate?

mTOR Stimulates	Purpose

Protein synthesis

Builds muscle and tissue

Ribosome biogenesis

Increases protein production capacity

Cell growth

Enlarges and strengthens cells

Inhibits protein breakdown

Preserves muscle mass

Nutrient metabolism

Supports energy storage and anabolic state

What are the primary methods for how humans cool themselves?

• convection

• evaporation

• conduction

• radiation

Why is exercise in a hot humid environment challenging for humans?

Challenge	Result

High humidity

Reduced sweat evaporation

High temperature

Faster heat buildup

More sweating

Greater dehydration risk

Blood to skin (not muscle)

Less oxygen delivery, fatigue

Core temp rises

Risk of heat-related illness

What is the primary concept for why altitude presents a challenge for
humans to perform at peak potential?

Lower oxygen pressure = less oxygen for metabolism = reduced performance.

How does this affect us at a cardiopulmonary level?

At the cardiopulmonary level, increased body fat — especially in obesity — affects both the heart and lungs by increasing workload, reducing efficiency, and raising health risks.

Exercise-induced muscle cramps:

sudden involuntary muscle contractions

during or after exercise

Heat syncope:

orthostatic dizziness attributed to dehydration, hypotension, venous pooling 

Heat exhaustion:

inability to effectively exercise in the heat due to cardiovascular insufficiency, hypotension, or central fatigue

Exertional heat stroke:

characterized by neuropsychiatric impairment and a high body temperature; medical emergency