How heart rate, breathing rate and breath volume change in exercise, working with the data, and oxygen debt.
What you will learn
- Explain why heart rate and breathing rise during exercise
- Calculate means, ranges and percentage increases from exercise data
- Calculate cardiac output
- Explain muscle fatigue and oxygen debt (Higher)
Why everything speeds up
Working muscles respire faster, so they need more oxygen and glucose and make more carbon dioxide.
- Heart rate rises, so blood carries oxygen and glucose to the muscles faster and takes carbon dioxide away.
- Breathing rate and the volume of each breath rise, so more oxygen enters the blood and more carbon dioxide leaves.
volume breathed per minute = volume per breath × breaths per minute
cardiac output = stroke volume × heart rate
Cardiac output is on the Edexcel specification: learn it there. Stroke volume is the blood pumped by one beat, in cm³.
The rest of this lesson and its 11 practice questions are locked.
In this lesson
- Why everything speeds up
- Working with exercise data
- Fatigue and oxygen debt
- Try it: A percentage change
11 practice questions, marked as you go; about 20 minutes in all.
Key terms
Heart rate, Breathing rate, Volume of each breath, Lactic acid, Oxygen debt
In this unit: Bioenergetics: photosynthesis and respiration
Photosynthesis and its rate, limiting factors and the pondweed practical, aerobic and anaerobic respiration, exercise and metabolism.