The table below shows measurements from a student after completing a three-minute step exercise. The student sat still while their breathing rate was counte...
Question 1 Report
The table below shows measurements from a student after completing a three-minute step exercise. The student sat still while their breathing rate was counted.
| Time after exercise / min | Breathing rate / breaths per min | Pulse rate / beats per min |
|---|---|---|
| 0 | 38 | 154 |
| 2 | 27 | 118 |
| 5 | 18 | 82 |
| 10 | 14 | 70 |
(a) State the breathing rate immediately after exercise. [1]
(b) Calculate the decrease in pulse rate between 0 minutes and 5 minutes. [1]
(c) Describe the relationship between time after exercise and breathing rate. [2]
(d) Explain why the breathing rate remains above the likely resting rate for several minutes. [2]
Answer Details
(a) Immediately after exercise, at 0 minutes, the breathing rate is 38 breaths per min. [1]
(b) Use the pulse rates at 0 and 5 minutes:
\[154 - 82 = 72\]
The pulse rate decreases by 72 beats per min. [1]
(c) Breathing rate decreases as time after exercise increases. The decrease is rapid at first, from 38 to 27 breaths per min, and then becomes slower as it approaches the resting rate. [2]
(d) Breathing remains above the likely resting rate because extra oxygen is needed to oxidise or remove lactic acid and repay the oxygen debt. Extra carbon dioxide produced during exercise also needs to be removed. [2]
Download The App On Google Playstore
Everything you need to excel in your exams
