Practical: The Effect of Exercise on Breathing

Breathing rate

Number of breaths taken per minute

Tidal volume

Amount of air breathed in or out per breath

Ventilation rate

Breathing rate × tidal volume

Exercise

Physical activity that increases energy demand

Respiration

Process releasing energy from glucose

Aerobic respiration

Respiration using oxygen

Anaerobic respiration

Respiration without oxygen

Oxygen debt

Extra oxygen needed after exercise to remove lactic acid

Lactic acid

Substance produced during anaerobic respiration

Stopwatch

Used to measure time during breathing experiments

Pulse

Heartbeat felt in arteries, increases during exercise

Fair test

Keeping variables constant except the one being tested

What happens to breathing rate during exercise?

It increases

Why does breathing rate increase during exercise?

To supply more oxygen to muscles

What happens to tidal volume during exercise?

It increases

What happens to ventilation rate during exercise?

It increases

Why does ventilation rate increase?

To remove more carbon dioxide and supply more oxygen

Why do muscles need more oxygen during exercise?

For increased aerobic respiration

What happens if oxygen supply cannot meet demand?

Anaerobic respiration occurs

What is produced during anaerobic respiration in muscles?

Lactic acid

Why does lactic acid cause fatigue?

It builds up in muscles

What is oxygen debt?

Extra oxygen needed to break down lactic acid after exercise

How can breathing rate be measured?

Count breaths per minute

How can pulse rate be measured?

Count beats per minute at the wrist or neck

Why must the same person be used in the experiment?

To keep the test fair

Why must exercise intensity be controlled?

To ensure results are comparable

Why should the experiment be repeated?

To improve reliability

What happens to pulse rate during exercise?

It increases

Why does pulse rate increase during exercise?

To deliver more oxygen and glucose to muscles