Exercise Physiology Exam 3 Review

What can cause metabolic ketoacidosis?

Excess production of ketone bodies from prolonged fasting, uncontrolled diabetes (insulin deficiency), or heavy alcohol use.

What can cause metabolic alkalosis?

Loss of H+ (vomiting, gastric suction), excess bicarbonate intake, or diuretic use that increases HCO3− relative to H+.

How is hydrogen (H+) produced during exercise?

From ATP hydrolysis and anaerobic glycolysis (lactic acid dissociation), and increased CO2 production (carbonic acid).

Which sports disrupt acid-base balance the most?

High-intensity, intermittent and sprint-type sports that rely heavily on anaerobic glycolysis (e.g., sprinting, rowing sprints, wrestling, 400-800 m events).

What does excess H+ inhibit and what does it compete with?

Excess H+ inhibits enzymes and metabolic pathways and competes with Ca2+ for binding sites on troponin, impairing muscle contraction.

Name the main buffers that act during exercise.

Intracellular proteins, muscle bicarbonate, intracellular phosphate groups, blood bicarbonate system, hemoglobin, and carnosine (muscle).

How is H+ buffered inside muscle (%)?

~60% by intracellular proteins, 20-30% by muscle bicarbonate, and 10-20% by intracellular phosphate groups.

Radiation

Running on a cool, cloudy morning where your warmer body emits heat to the cooler air.

Conduction

Gripping a cold metal barbell, which draws heat from your hands.

Convection

Using a fan during indoor training to promote airflow and cool the body.

Evaperation

Sweating heavily during a hot practice, where sweat evaporates and cools the skin.

What is POAH and its role?

Preoptic area of the anterior hypothalamus — the body's thermostat that integrates temperature signals and coordinates effector responses for heat gain/loss.

How does the body respond to an increase in core temperature?

Vasodilation (increase skin blood flow), sweating (evaporation), decreased shivering, and behavioral responses (seek shade/cool).

How does the body respond to a decrease in core temperature?

Vasoconstriction, shivering thermogenesis, increased muscle tone, and behavioral responses (seek warmth).

During fever, how does the POAH change to increase body temperature?

Set point in POAH is raised (pyrogens cause upward reset) → mechanisms that conserve/generate heat are activated (shivering) until new set point reached.

Given a scenario of impaired heat loss, what common problems might impair evaporation?

High humidity (reduces evaporation), dehydration (reduced sweat), occlusive clothing, or impaired sweating (e.g., certain meds).

How can exercise-heat injuries be prevented?

Acclimatization, hydration, appropriate clothing, scheduling workouts for cooler times, monitoring environmental heat stress, and adjusting intensity/duration.

What body weight loss from dehydration impairs performance?

1-2% body weight loss from dehydration can impair exercise performance.

Hydration guideline: how much to drink within 3 hours prior to event?

400-800 mL within three hours prior to event.

Hydration guideline: how much to drink every 15-20 minutes during exercise?

150-300 mL every 15-20 minutes (adjust volume for environment/sweat rate).

Recommended rehydration after exercise (fluid replacement relative to weight lost)?

Consume ~150% of weight lost (1 kg body weight = 1.5 L fluid replacement).

How can urine be used to monitor hydration?

Monitor urine color — darker indicates dehydration; pale indicates better hydration.

Are some sports drinks superior to water for rehydration? Why?

Yes — drinks with electrolytes and carbohydrate can enhance fluid retention and restore electrolytes and provide fuel.

What are the 3 major factors contributing to accelerated muscle fatigue in heat?

Central nervous system (CNS) fatigue, reduced muscle contractility from metabolic disturbances, and cardiovascular strain (reduced muscle blood flow).

What is CNS dysfunction

Decreased motivation, reduced voluntary activation of motor units

What is CNS fatigue

a reduction in the brain and spinal cord's ability to activate muscles effectively. It develops when prolonged or intense exercise causes Slower reaction times and mental fatigue

What is physiological acclimatization to heat? Name changes.

Adaptations from repeated heat exposure: increased plasma volume, increased sweat rate, earlier onset of sweating, lower core temperature during exercise, improved cardiovascular stability.

Principles of training — define Overload, Specificity, Reversibility.

Overload: training stimulus must exceed normal to induce adaptation. Specificity: adaptations are specific to the type of training. Reversibility: gains are lost when training ceases.

How much can VO2max improve with training (typical ranges)?

Varies by baseline fitness — untrained individuals can see larger improvements (20-40%); trained individuals see smaller gains.

Acute training-induced changes in first days: typical plasma volume and VO2max changes?

~11% ↑ plasma volume, ~7% ↑ VO2max, and ~10% ↑ stroke volume within first ~6 days of endurance training.

Training increases maximal stroke volume — list contributing mechanisms.

↑ Preload (EDV), ↑ plasma volume, ↑ venous return, ↑ ventricular chamber size; ↓ afterload (TPR), ↑ contractility, and ↑ maximal muscle blood flow.

Endurance adaptations — what happens to muscle blood flow and A-V O2 difference?

Maximal muscle blood flow increases and A-V O2 difference increases (more extraction).

How does endurance training shift muscle fiber type?

A shift from fast to slower phenotype (e.g., IIX → IIa → I) and increased capillary density.

What does increased mitochondrial volume lead to (in terms of ADP and energy)?

Increased mitochondria lower the ADP concentration required to stimulate ATP production → smaller oxygen deficit and improved oxidative phosphorylation efficiency.

How does endurance training reduce oxygen deficit?

Faster activation of oxidative metabolism due to ↑ mitochondrial content and enzyme activity, leading to quicker ATP production aerobically.

What is AMPK?

An energy sensor that promotes mitochondrial biogenesis and substrate uptake.

What is the retraining effect on VO2max?

Some VO2max gains are lost quickly with detraining, but retraining regains adaptations faster than initial training.

Which energy system supports sprint interval training (SIT)?

Primarily the ATP-PC system and glycolysis.

What is the approximate energy contribution for HIIT of ~60 seconds?

~70% anaerobic and ~30% aerobic.

What does a proper work ratio ensure in interval training?

It ensures the intended energy system is targeted.

What training promotes the IIX to IIa fiber shift?

Endurance and repeated high-volume training with moderate intensity.

What training promotes the IIX to IIx/IIa shift?

High-intensity interval training (sprinting)

What training promotes the IIx/IIa to I shift?

Long, steady-state running, cycling, swimming (endurance training)

What does sprint interval training (SIT) improve?

Anaerobic capacity, power, and mitochondrial and metabolic adaptations.

What is sarcopenia?

Age-related loss of muscle mass and function, with preferential atrophy of fast-twitch fibers. Type IIa and Type IIx

What are the neural adaptations responsible for early strength gains?

Increased neural drive, motor unit recruitment, firing rates, synchronization, and improved coordination.

Why are motor neuron adaptations important for strength?

They increase force production without hypertrophy by improving neural recruitment.

Who is typically stronger: bodybuilders or strongmen?

Strongmen, due to training for neural factors emphasizing maximal force.

Why is intensity important in resistance training?

It determines recruitment of high-threshold motor units and drives maximal strength adaptations.

What molecular factors are associated with muscle protein synthesis?

mTOR pathway activation, including mTOR, Rheb, and PA.

What is Rheb?

A small GTPase that activates mTOR signaling.

What is the role of phosphatidic acid (PA) in muscle?

It helps activate mTOR and stimulates muscle protein synthesis.

What does mTOR do?

It regulates cell growth and protein synthesis in response to nutrients and mechanical load.

What is concurrent training?

Combining endurance and resistance training, which can reduce strength gains.

What mechanisms cause concurrent training interference?

AMPK activation can inhibit mTOR signaling and increase fatigue.

What adaptations occur early in resistance training?

Neural adaptations predominate, leading to increased strength without large hypertrophy.

What happens to protein synthesis with overtraining?

It can be depressed due to chronic fatigue and hormonal changes.

How does endurance training affect acid-base regulation?

It improves buffering capacity and reduces reliance on anaerobic glycolysis.

What is the functional effect of increased antioxidant capacity with training?

Reduced oxidative damage and improved recovery.

What training-induced change occurs in fuel utilization?

Increased reliance on fat oxidation at submaximal intensities.

What cardiovascular changes occur in marathon training?

Increased VO2max, plasma volume, stroke volume, and capillarity in muscle.

What hydration strategy should an athlete follow?

Hydrate days prior, drink 400-800 mL before, and 150-300 mL during activity.

How does high humidity affect thermoregulation?

It reduces evaporative heat loss, increasing the risk of hyperthermia.

What are signs of dehydration impairing performance?

>1-2% body weight loss, dark urine, decreased endurance, increased heart rate.

Which intracellular buffer plays the largest role in skeletal muscle?

Intracellular proteins.

Why can increased contractility occur after endurance training?

Improved calcium handling and enhanced mitochondrial function contribute to increased contractility.