NCERT Class 9 Physical Education Chapter 6 Cardiorespiratory System Solutions English Medium As Per New Syllabus. to each chapter is provided in the list so that you can easily browse through different chapters NCERT Class 9 Physical Education Chapter 6 Cardiorespiratory System Notes and select need one. NCERT Class 9 Physical Education Chapter 6 Cardiorespiratory System Question Answers Download PDF. NCERT Class 9 Physical Education And Well – Being Texbook Solutions.
NCERT Class 9 Physical Education Chapter 6 Cardiorespiratory System
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Cardiorespiratory System
Chapter: 6
| Unit – 2 Science and Sports |
| EXERCISES |
1. In the Preparatory and Middle stages, you practised different physical activities, including warm-up and cool-down exercises. List five activities that help improve cardiovascular endurance.
Ans: Based on the sources, five physical activities that help improve cardiovascular endurance include:
(i) Jogging.
(ii) Running.
(iii) Jumping jacks.
(iv) Cycling.
(v) Stair climbing.
2. Measure your heart rate while stair climbing and cycling. Compare the changes in heart rate and breathing rate for both activities by creating a chart and recording the differences.
Ans: While creating an exact chart requires you to measure your own body’s data, the scientific changes that occur during such vigorous activities are as follows:
(i) Changes in Heart Rate: A normal resting heart rate for adults is about 70–80 beats per minute. During exercises like stair climbing and cycling, the heart beats 2 to 3 times faster to pump blood more quickly to the working muscles.
(ii) Changes in Breathing Rate: At rest, a normal breathing rate is typically 12–15 breaths per minute. During intense physical activity, your breathing becomes faster and deeper to take in more oxygen for cellular respiration, causing the rate to rise to over 40 breaths per minute.
3. Do one activity each using your upper body and one using your lower body. Identify and explain the differences in muscle use, tiredness, and heart rate between the two activities.
Ans: (i) Muscle Use and Blood Flow: When you perform an activity, blood flow changes specifically to support the body tissues being used. For example, if you do a lower body activity like the leg press, the blood flow will be much higher in the lower body tissues compared to the upper body. During such exercises, blood flow to the active muscles increases by 15 to 25 times to deliver oxygen and nutrients.
(ii) Tiredness (Fatigue): The specific muscle group you use will experience tiredness because the muscle fibres are contracting more often and requiring more energy. This intense activity leads to the production of waste products, such as carbon dioxide and lactic acid, which the body must work at a higher rate to remove.
(iii) Heart Rate: Regardless of whether the activity focuses on the upper or lower body, your overall heart rate will increase significantly. This happens because the heart must pump more blood (up to 30 litres per minute during maximal exercise) to send oxygen-rich blood to whichever tissues are currently active.
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