[MOD16A - PHYSIO] Exercise Physiology_2028

[T/F] Exercise is a form of stress.

TRUE

How does female muscle contraction force compare to male muscle contraction force?

They are similar (3-4 kg/cm²)

[T/F] The total muscle performance differences between sexes are mainly due to differing muscle quality.

FALSE. They are due to greater muscle mass in males.

A hormone that increases protein deposition and muscle size in males

Testosterone

A hormone that promotes fat deposition in hips, breasts, and subcutaneous tissues in females

Estrogen

[T/F] Increased body fat is advantageous for all sports performance.

FALSE. It can impair strength-to-weight ratio.

The ability to generate maximal force by a muscle or group

Strength

The ability to do work in a unit time (force × distance)

Power

The ability to sustain muscle contraction over time

Endurance

What is the unit used to measure power in exercise?

Kilogram meters per minute (kg-m/min)

Which type of diet supports the highest muscular endurance?

High-carbohydrate diet

What is the immediate energy source for muscle contraction?

Adenosine triphosphate (ATP)

How much energy does one mole of ATP provide?

7300 calories per phosphate bond

How long can stored ATP sustain maximal power output?

About 3 seconds

How much energy does phosphocreatine provide per mole?

10,300 calories

How long can the phosphagen energy system support maximal activity?

8-10 seconds

What is the fate of pyruvic acid during low oxygen conditions?

It is converted into lactic acid

Which energy system has the slowest ATP production rate?

Aerobic system

How long can the aerobic system sustain power output?

Indefinitely, as long as fuel and oxygen are available

Which system is most suitable for short bursts of high-intensity activity?

Phosphagen system

What causes the burning sensation during intense muscle activity?

Lactic acid accumulation

How much stored oxygen is normally available in the body?

2 liters

Which macronutrient becomes the major energy source after 3-4 hours of exercise?

Fats

Which supplement is often used during marathon events to maintain energy?

Glucose drinks/solutions

What fuel source is preferred during intense muscular exertion?

Muscle glycogen and blood glucose

[T/F] Carbohydrates are the dominant energy source in endurance training.

TRUE

What happens when muscles are trained daily at over 50% max force?

They rapidly gain strength and hypertrophy

Which contributes more to muscle hypertrophy: increased fiber number or diameter?

Increased fiber diameter

[T/F] Fast-twitch fibers are better suited for endurance activities.

FALSE. They are designed for quick, powerful contractions.

What is the normal oxygen consumption rate for a man at rest?

250 mL/min

[T/F] There is a linear relationship between oxygen consumption and pulmonary ventilation.

TRUE

What is the typical pulmonary ventilation at maximal exercise?

100-110 L/min

What is the maximal breathing capacity in healthy individuals?

150-170 L/min

What is the significance of the difference between maximal breathing capacity and actual pulmonary ventilation?

Provides a safety window for extreme conditions (e.g. heat, altitude, respiratory disease)

[T/F] Blood gas levels become abnormal during maximal exercise.

FALSE. Blood gases usually remain normal due to respiratory efficiency.

What primarily stimulates respiration during heavy exercise?

Neurogenic mechanisms, not changes in blood gases

What happens to muscle blood flow during moderately strong intermittent contractions?

It increases markedly

[T/F] Muscle contraction always increases blood flow.

FALSE. Strong contractions can temporarily reduce it by compressing vessels.

Describe the relationship between muscle work, oxygen consumption, and cardiac output.

All increase linearly with one another

What is the cardiovascular adaptation seen in marathon runners?

40% increase in cardiac output and cardiac mass

[T/F] Resting cardiac output is higher in trained athletes than untrained individuals.

FALSE. It is similar, but achieved via lower heart rate and higher stroke volume.

What accounts for most of the increase in cardiac output during exercise?

Increased heart rate

At what point does stroke volume reach its maximum during exercise?

When cardiac output is about halfway to its maximum

[T/F] Beyond the halfway point of cardiac output, only heart rate increases further.

TRUE

What percentage of maximal capacity does cardiac output reach during maximal exercise?

About 90%

What percentage of maximal pulmonary ventilation is typically used during maximal exercise?

About 65%

Which system is the limiting factor during maximal exercise: cardiovascular or respiratory?

Cardiovascular system

Why is cardiovascular performance the limiting factor in oxygen delivery during maximal exercise?

Because it reaches maximum output before the respiratory system does

What is the most important physiological benefit of endurance training?

Increased cardiac output

How much of the body's energy is converted into heat during exercise?

About 75-80%

What is the relationship between heat liberation and oxygen consumption?

Directly proportional

What is the typical body temperature during endurance exercise in normal conditions?

37-40°C

At what body temperature does heat stroke become dangerous?

41-42°C

How is heat stroke treated?

Rapidly reduce body temperature; total immersion in ice water if needed

What is the effect of losing 3% of body weight through sweat?

Greatly decreases performance

[T/F] Salt tablets are always beneficial for exercise in hot conditions.

FALSE. Overuse can cause harm.

What hormone facilitates sweat gland acclimatization by reabsorbing NaCl?

Aldosterone

What is a consequence of aldosterone-induced NaCl reabsorption during exercise?

Increased potassium loss in urine and sweat

What causes exercise-associated hyponatremia?

Drinking hypotonic fluids with Na+ concentration < 18 mmol/L

What life-threatening condition can hyponatremia cause?

Brain edema

What is the effect of caffeine on performance in some studies?

Up to 7% improvement in running time

What is the actual effect of amphetamine and cocaine abuse in athletes?

Performance deterioration due to catecholamine interaction

What is a severe cardiac consequence of amphetamine overuse?

Ventricular fibrillation

How much lower is mortality in fit individuals aged 50-70 compared to unfit peers?

About 3× lower

Why is physical fitness protective in old age illness like pneumonia?

Larger respiratory and cardiac reserves improve survival

Give two examples of extreme physiologic stress.

High grade fever — 100% increase in metabolism

Marathon race — 2000% increase in metabolism

Enumerate the physiological differences between males and females relevant to exercise.

Body size

Body composition

Testosterone levels

Enumerate performance differences between males and females in endurance events.

Female marathoners are 11% slower

Females outperform in English channel swims due to fat insulation and buoyancy

Enumerate the three components of muscle performance.

Strength

Power

Endurance

Enumerate glycogen storage levels (g/kg muscle) by diet type.

High-carb diet - 40 g/kg

Mixed diet - 20 g/kg

High-fat diet - 6 g/kg

Enumerate the three muscle metabolic systems used during exercise.

Phosphocreatine-creatine system

Glycogen-lactic acid system

Aerobic system

Enumerate the components of the phosphagen system.

ATP

Phosphocreatine

Enumerate the advantages of the glycogen-lactic acid system.

Does not require oxygen

Fast ATP production (2.5x faster than aerobic)

Supports short to moderate activity duration

Enumerate the drawbacks of the glycogen-lactic acid system.

Half as rapid as phosphagen system

Only supports 1.3-1.6 minutes of maximal activity

Enumerate the fuels oxidized by the aerobic system.

Glucose

Fatty acids

Amino acids

Compare ATP production rates (mol/min) across systems.

Phosphagen - 4

Glycolytic - 2.5

Aerobic - 1

Enumerate the two mechanisms for lactic acid removal.

Conversion to pyruvic acid and oxidation

Conversion to glucose in the liver (gluconeogenesis)

Enumerate the locations of oxygen storage in the body.

Lungs - 0.5 L

Body fluids - 0.25 L

Hemoglobin - 1 L

Myoglobin - 0.3 L

What is oxygen debt?

The extra oxygen required to restore ATP, PC, and remove lactic acid post-exercise

Enumerate the two components of oxygen debt.

Alactic portion - 3.5 L

Lactic acid portion - 8 L

[T/F] Glycogen recovery is quick and completed in hours.

FALSE. Full recovery takes up to 2 days with high-carb diet.

Enumerate the major fuel sources used by muscles during prolonged exercise.

Carbohydrates (glucose, glycogen)

Fats (fatty acids, ketones)

Proteins (amino acids)

Enumerate structural changes that occur in hypertrophied muscles.

Increased myofibrils

120% ↑ mitochondrial enzymes

60-80% ↑ phosphagen system (ATP + PC)

50% ↑ glycogen stores

75-100% ↑ triglycerides

Enumerate key characteristics of fast-twitch muscle fibers.

2× larger than slow-twitch

High phosphagen/GLA enzyme activity

Short-duration, high-power output

Enumerate key characteristics of slow-twitch muscle fibers.

More mitochondria

More myoglobin

More aerobic enzymes

More capillaries

Enumerate the O2 consumption rates (mL/min) for different athletic levels.

Untrained male - 3600

Trained male - 4000

Marathon runner - 5100

Enumerate the respiratory effects of smoking.

Nicotine constricts terminal bronchioles

Smoke causes fluid secretion and epithelial swelling

Nicotine paralyzes cilia -> debris accumulation

Enumerate two effects of muscle contraction on blood flow.

Strong contraction compresses blood vessels, reducing flow

Exercise increases blood flow up to 25-fold

Enumerate effects of heart disease and aging on exercise capacity.

Heart disease — difficulty with simple movements (e.g. climbing)

Old age — 50% drop in maximal cardiac output from age 18 to 80

Enumerate reasons why muscle work still becomes body heat.

Overcoming viscous resistance in joints

Friction in blood flow

Intracellular inefficiencies

Enumerate symptoms of heat stroke.

Extreme weakness

Exhaustion

Headache

Dizziness

Nausea

Profuse sweating

Confusion

Collapse

Unconsciousness

Enumerate the effects of losing 5-10 lbs of body fluid during exercise.

Mainly from sweat

Significant performance drop

Cramps and nausea

Enumerate cardiovascular risks associated with anabolic steroids.

Hypertension

Increased LDL

Decreased HDL

Higher risk of heart attack and stroke

Enumerate the health benefits of fitness.

Reduced cardiovascular disease

Increased body reserves for illness

Reduced risk of Type 2 DM, obesity, and cancers