What is the human breathing rate during hard physical work?
Correct answer: D. 30-40 times per minute
- A. 10 to 15 times per minute
- B. 10 to 20 times per minute
- C. 80 to 120 times per minute
- D. 30-40 times per minute
Explanation
When you exercise and your muscles work harder, your body uses more oxygen and produces more carbon dioxide. To cope with this extra demand, your breathing has to increase from about 15 times a minute (12 litres of air) when you are resting, up to about 30-40 times a minute (100 litres of air) during exercise.
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About Respiration
The human respiratory system includes the air passages, lungs, alveoli and breathing muscles, while gaseous exchange explains how oxygen enters blood and carbon dioxide leaves it by diffusion. The effects of smoking include damage to cilia and alveoli, reduced gas exchange, chronic bronchitis, emphysema and increased risk of lung cancer.
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