Exercise physiology Practice Questions
20 free Exercise physiology practice questions for the Physiology. Tap an option to answer — you get instant feedback, the correct answer, and a detailed explanation for every question.
Which physiological parameter best reflects maximal aerobic capacity during exercise?
- A Resting heart rate
- B VO2 max
- C Respiratory quotient
- D Blood lactate level
Correct answer: VO2 max
VO2 max represents the maximum rate of oxygen consumption during intense exercise and is the best indicator of aerobic fitness. It reflects the integrated function of the cardiovascular, respiratory, and muscular systems.
During the initial phase of moderate exercise, the immediate source of ATP for muscle contraction is primarily derived from:
- A Oxidative phosphorylation
- B Glycogenolysis
- C Phosphocreatine breakdown
- D Beta-oxidation of fatty acids
Correct answer: Phosphocreatine breakdown
Phosphocreatine provides a rapid source of high-energy phosphate to regenerate ATP during the first few seconds of exercise. It supports muscle contraction before slower metabolic pathways are activated.
Which change occurs in skeletal muscle fibers as a result of endurance training?
- A Decrease in mitochondrial density
- B Increase in capillary supply
- C Shift from type I to type II fibers
- D Reduced oxidative enzyme activity
Correct answer: Increase in capillary supply
Endurance training increases capillary density, improving oxygen delivery to muscle fibers. It also enhances oxidative capacity rather than reducing it.
The term 'oxygen deficit' during exercise refers to:
- A The amount of oxygen lacking in circulating arterial blood
- B Gap between oxygen need and uptake at exercise onset
- C Reduced oxygen saturation during recovery
- D Excess oxygen consumed after exercise
Correct answer: Gap between oxygen need and uptake at exercise onset
Oxygen deficit is the gap between the oxygen required for a given workload and the oxygen actually consumed at the start of exercise. It occurs because aerobic metabolism takes time to reach steady state.
Which hormone plays a major role in increasing blood glucose levels during prolonged exercise?
- A Insulin
- B Growth hormone
- C Glucagon
- D Thyroxine
Correct answer: Glucagon
Glucagon promotes glycogenolysis and gluconeogenesis in the liver during exercise. This helps maintain blood glucose levels when muscular demand is high.
During intense anaerobic exercise, fatigue is most closely associated with the accumulation of:
- A Carbon dioxide
- B Lactic acid and hydrogen ions
- C Creatinine
- D Urea
Correct answer: Lactic acid and hydrogen ions
Accumulation of lactic acid and hydrogen ions lowers intracellular pH, impairing enzyme activity and muscle contraction. This contributes significantly to fatigue during high-intensity exercise.
Which cardiovascular adaptation is commonly seen in trained endurance athletes?
- A Decreased stroke volume
- B Increased resting heart rate
- C Increased maximal cardiac output
- D Reduced ventricular compliance
Correct answer: Increased maximal cardiac output
Endurance training increases stroke volume and maximal cardiac output. This allows more blood and oxygen to be delivered to working muscles during exercise.
The primary factor responsible for increased ventilation during exercise is:
- A Increased arterial carbon dioxide partial pressure
- B Decreased arterial oxygen saturation
- C Neural input from motor cortex and muscles
- D Reduced blood pH at rest
Correct answer: Neural input from motor cortex and muscles
Neural signals from the motor cortex and proprioceptors rapidly stimulate ventilation at the onset of exercise. This mechanism acts before significant chemical changes occur in the blood.
Which muscle fiber type is most resistant to fatigue?
- A Type IIb fibers
- B Type IIa fibers
- C Type I fibers
- D Fast glycolytic fibers
Correct answer: Type I fibers
Type I fibers have high mitochondrial content and rely mainly on aerobic metabolism. This makes them highly resistant to fatigue during prolonged activity.
The respiratory quotient (RQ) during pure carbohydrate metabolism is approximately:
- A 0.7
- B 0.8
- C 0.9
- D 1.0
Correct answer: 1.0
An RQ of 1.0 indicates that equal amounts of carbon dioxide are produced and oxygen consumed, which is characteristic of carbohydrate oxidation.
Which factor primarily limits VO2 max in healthy individuals?
- A Muscle mitochondrial capacity
- B Pulmonary diffusion capacity
- C Cardiac output
- D Hemoglobin concentration alone
Correct answer: Cardiac output
Cardiac output is the main limiting factor for VO2 max in healthy people. It determines how much oxygenated blood can be delivered to active muscles.
Excess post-exercise oxygen consumption (EPOC) is mainly required for:
- A Replenishing depleted muscle glycogen stores only
- B Removing lactate and restoring ATP-PC stores
- C Raising overall body core temperature further
- D Sustaining a persistently elevated heart rate
Correct answer: Removing lactate and restoring ATP-PC stores
EPOC represents the extra oxygen consumed after exercise to restore phosphocreatine, convert lactate, and normalize physiological variables. It supports recovery processes.
During prolonged submaximal exercise, the major fuel source gradually shifts toward:
- A Muscle glycogen
- B Blood glucose
- C Fatty acids
- D Amino acids
Correct answer: Fatty acids
As exercise continues, fatty acid oxidation increases to conserve limited glycogen stores. This shift supports sustained energy production.
Which change occurs in blood flow distribution during dynamic exercise?
- A Sharply reduced flow to working skeletal muscles
- B Markedly increased flow to the kidneys
- C Increased flow to skin and active muscles
- D Uniform, unchanged flow to every organ
Correct answer: Increased flow to skin and active muscles
During exercise, blood flow is redistributed to active muscles and skin to support metabolism and heat dissipation. Flow to organs like kidneys is reduced.
The lactate threshold is defined as:
- A The point of maximal attainable oxygen consumption
- B The intensity at which blood lactate rises sharply
- C The threshold at which exercising muscles begin to ache
- D The rate of lactate clearance from the bloodstream
Correct answer: The intensity at which blood lactate rises sharply
Lactate threshold marks the exercise intensity at which lactate production exceeds its clearance. It is an important predictor of endurance performance.
Which respiratory adaptation occurs with regular aerobic training?
- A Increased ventilation while completely at rest
- B Decreased overall pulmonary lung compliance
- C Improved efficiency of oxygen extraction
- D Reduced tidal volume during heavy exercise
Correct answer: Improved efficiency of oxygen extraction
Aerobic training improves the efficiency of oxygen extraction by tissues. Ventilatory capacity becomes better matched to metabolic demand.
Which factor contributes most to heat loss during vigorous exercise in a warm environment?
- A Radiation of heat from exposed skin
- B Direct conduction to cooler surfaces
- C Convection currents around the body
- D Evaporation of sweat
Correct answer: Evaporation of sweat
Evaporation of sweat is the most effective mechanism for heat loss during exercise, especially in warm conditions. It dissipates large amounts of body heat.
Which metabolic pathway predominates during a 100-meter sprint?
- A Aerobic oxidation
- B Anaerobic glycolysis
- C Phosphagen system
- D Beta-oxidation
Correct answer: Phosphagen system
The phosphagen system provides rapid ATP generation through phosphocreatine breakdown. It is the primary energy source for very short, high-intensity efforts.
Why does systolic blood pressure increase during dynamic exercise?
- A Increased peripheral resistance
- B Decreased venous return
- C Increased cardiac output
- D Reduced arterial compliance
Correct answer: Increased cardiac output
Systolic blood pressure rises mainly due to increased cardiac output during exercise. Peripheral resistance usually decreases in active muscles.
Which adaptation improves oxygen delivery to muscles following endurance training?
- A Decreased hemoglobin affinity for oxygen
- B Increased blood viscosity
- C Increased capillary-to-fiber ratio
- D Reduced red blood cell count
Correct answer: Increased capillary-to-fiber ratio
An increased capillary-to-fiber ratio shortens diffusion distance for oxygen. This enhances oxygen delivery and utilization by muscle cells.