Effects of Exercise

Overview

Unit: Exploring Respiration Processes
Lesson: 2 of 4
Duration: 60 minutes
Class: Year 8 (12–13 years old)
Class size: 30 students

---

National Curriculum Links

Subject: Science
Strand: Biology – Respiration in living organisms

Relevant Programmes of Study (Year 8)

• Working scientifically: Plan a scientific enquiry to answer questions, including recognising and controlling variables where necessary.
• Biology:
  • Cells and organisation: Understand that respiration is a chemical reaction in cells.
  • Interdependence and adaptation: Explore how humans respond to exercise by increasing heart and breathing rates as part of maintaining aerobic respiration.
  • Practical skills: Measure and compare heart and breathing rates under different conditions.

---

Learning Objectives

By the end of this lesson, students will be able to:

1. Describe the role of respiration in releasing energy.
2. Explain how heart and breathing rates change during and after exercise.
3. Plan and conduct a simple investigation measuring heart rate and breathing rate before and after exercise.
4. Analyse and interpret their data to explain the link between exercise and increased respiration demand.

---

Key Vocabulary

• Respiration
• Aerobic respiration
• Heart rate
• Breathing rate
• Variables (independent, dependent, controlled)
• Pulse
• Investigation
• Data interpretation

---

Resources

• Stopwatch or timer (1 per pair)
• Pupil handouts: Investigation worksheet (procedure, data table)
• Whiteboard and markers
• Pulse rate charts for reference
• Space for light exercise (hall or outdoors)
• Sensor equipment (optional; e.g., digital pulse oximeter or breathing rate monitor, if available)

---

Lesson Structure

1. Starter (5 minutes)

Engage curiosity and activate prior knowledge.

• Quick quiz: “What happens to your breathing when you run or climb stairs?” (Whole class brainstorm — answers recorded on whiteboard.)
• Recap from Lesson 1: What is respiration and why do our cells need energy?

---

2. Introduction to Investigation (10 minutes)

Explain concepts and scientific method.

• Teacher mini-presentation:
  • Recap aerobic respiration: glucose + oxygen → energy + carbon dioxide + water.
  • Importance of oxygen during exercise.
  • How heart and breathing rates supply oxygen to muscles.
• Introduce investigation question: How does exercise affect heart and breathing rates?
• Discuss variables:
  • Independent = exercise (before and after)
  • Dependent = heart and breathing rates
  • Controlled = resting conditions, exercise type, measurement timings
• Model correct method to measure pulse and breathing rate.

---

3. Practical Activity (25 minutes)

Plan and carry out the investigation in pairs.

• Pupils will:
  • Measure their resting heart rate and breaths per minute (count breaths by watching chest).
  • Perform 2 minutes of moderate exercise (e.g., star jumps, running on spot).
  • Immediately measure heart and breathing rates post-exercise.
  • Record their results on worksheet.
• Teacher circulates: checks for correct technique, assists students.

---

4. Data Analysis and Discussion (15 minutes)

Analyse results and tie back to respiration.

• Pairs calculate average before/after rates.
• Class discusses:
  • What patterns do we see?
  • Why do the heart and breathing rates increase?
  • How does this relate to energy demand and respiration in cells?
• Teacher links back to key processes: more oxygen needed → increased breathing → heart pumps faster → more oxygenated blood delivered.

---

5. Plenary and Assessment (5 minutes)

Consolidate learning and assess understanding.

• Exit tickets: each student writes one sentence explaining why heart and breathing rates increase after exercise.
• Class review: Did the investigation go as planned? What would improve the experiment?

---

Differentiation

• Support: Provide measuring templates, one-to-one support for pulse counting.
• Challenge: Encourage students to suggest reasons for inconsistencies in their data and how to improve control variables.

---

Extension / Homework (Optional)

• Research anaerobic respiration and write a short paragraph comparing it with aerobic respiration.
• Design a new investigation to measure heart rate after different types or intensities of exercise.

---

Teacher Reflection Notes

• Were variables named and controlled effectively?
• Did students understand the link between exercise and cellular respiration?
• Were practical skills (pulse and breathing rate measurement) carried out accurately?
• Could timings or conditions be adjusted for better student engagement?

---

This lesson actively promotes scientific enquiry, ensuring students apply knowledge and practical skills while linking biological concepts to real-life bodily responses in line with the National Curriculum's working scientifically requirements.