2.7.5Structure and Function in Living Organisms
Practical: The Effect of Exercise on Breathing
5 min read 6 parts Lesson 32 of 55 1 quiz
Section 1 of 6Variables
| Type | Variable | How it is handled |
|---|---|---|
| Independent | Physical activity (rest compared with exercise) | Participants sit, then perform the exercise |
| Dependent | Breathing rate in breaths per minute | Count the breaths over a set time |
| Control | Type and duration of exercise, age group, room temperature, rest time before measuring, time of day, counting method | Keep the same for every participant |
Section 2 of 6Method
1
Choose participants from a similar age group and explain what they will do; check that nobody has a health condition that makes exercise unsafe.
2
Ask each participant to sit quietly for a few minutes, then count their breaths for one minute (one breath is one inhale plus one exhale).
3
Have every participant do the same exercise, for example running on the spot for one minute.
4
Immediately after the exercise, count their breaths again for one minute.
5
Calculate the change: breathing rate after exercise minus breathing rate at rest.
6
Repeat for all participants and calculate a mean change in breathing rate.
Section 3 of 6Results and conclusion
Typical pattern
- Typical pattern Breathing rate after exercise is higher than at rest, and breaths are also deeper.
- The mean change shows the trend for the group and reduces the effect of any single unusual result.
Explanation
- Explanation Exercising muscles respire faster and produce more carbon dioxide.
- Faster, deeper breathing takes in more oxygen and removes carbon dioxide more quickly.
Section 4 of 6Limitations and improvements
Evaluation
Participant differences
- Participant differences Fitness, health and lifestyle vary between people, so it is hard to control them.
- Use the same group and compare each person with their own resting rate.
Exercise intensity
- Exercise intensity People may work harder or less hard. Use a fixed task such as step-ups at a set pace.
Counting accuracy
- Counting accuracy Breathing rate falls quickly after exercise and counts can be wrong.
- Start at once and count for 15 seconds, then multiply by four.
Conditions
- Conditions Temperature and stress affect breathing, so test indoors in the same conditions with a rest before starting.
Section 5 of 6Key terms
| Term | Meaning |
|---|---|
| Breathing rate | The number of breaths taken in one minute. |
| Independent variable | The factor deliberately changed in an investigation. |
| Dependent variable | The factor measured as the outcome. |
| Control variable | A factor kept the same so that it does not affect the results. |
| Mean | The total of the values divided by the number of values. |
Section 6 of 6Exam technique
1
Counting an inhalation and an exhalation as two separate breaths. One breath is a complete in-and-out cycle.
2
Starting the post-exercise count after a long delay, by which time the rate has already fallen.
3
Using different exercises for different people, which makes comparisons unfair.
4
Drawing a conclusion from one participant only; repeat with several and use a mean.