IB SEHS: Acute Physiological Responses to Exercise

• Design Technology (First Exam 2027)
• Digital Society (DS)
• Economics
• English A Lang & Lit
• English A Lit
• English B
• Environmental systems and societies (ESS)
• French A
• French ab initio
• French B

• Geography
• German A
• German ab initio
• German B
• Global Politics
• History
• Mathematics Analysis and Approaches (AA)
• Mathematics Applications & Interpretation (AI)
• Philosophy
• Physics

• Psychology
• Psychology (First Exam 2027)
• Spanish A
• Spanish ab initio
• Spanish B
• Sports, exercise and health science (SEHS)
• Theory of Knowledge (TOK)

Key acute cardiovascular responses to know:

• Heart rate increases almost immediately (autonomic nervous system stimulation).

• Stroke volume increases from rest to moderate intensity due to greater venous return and stronger contractions.

• Cardiac output increases because CO = HR × SV, meaning more blood is pumped each minute.

If you want a clean, exam-ready breakdown, use: Cardiovascular Responses to Exercise. And for the formula relationships, see Heart rate, stroke volume and cardiac output (notes).

Respiratory acute responses (more air, faster gas exchange)

Your lungs don’t “wait and see.” In IB SEHS, respiratory acute responses explain how the body increases oxygen uptake and removes carbon dioxide faster as exercise intensity rises.

Key acute respiratory responses:

• Breathing rate increases to move air more frequently.

• Tidal volume increases to move more air per breath.

• Ventilation increases (ventilation = breathing rate × tidal volume).

At higher intensities, tidal volume may plateau, so further rises in ventilation rely heavily on breathing rate. For a focused explanation, revise with: Respiratory Responses to Exercise Intensity. To tighten definitions for IB SEHS markschemes, this is useful: Pulmonary ventilation and tidal volume definitions (cheatsheet).

Muscular and metabolic acute responses (making ATP faster)

A simple way to remember this section for IB SEHS: your muscles immediately try to make energy faster, and heat is a side effect.

Key acute muscular/metabolic responses:

• Muscle temperature increases, improving flexibility and speeding contraction.

• Enzyme activity increases because many metabolic reactions run faster when warm.

• Rate of ATP production increases to meet the workload.

If you’re revising “response” as a whole topic, the syllabus-aligned practice hub helps: A.3 Response -- IB Questionbank and the matching recall tool: Flashcards for A.3 Response.

How to write high-mark acute response paragraphs

In IB SEHS, a high-scoring paragraph usually has three sentences:

1. What changes (name the variable).

2. Why it changes (tie to oxygen demand, CO2 production, homeostasis).

3. How it helps performance (delays fatigue, supports ATP production, maintains intensity).

Example pattern: “Heart rate increases during exercise to raise cardiac output, which delivers more oxygen to working muscles and removes carbon dioxide more efficiently, helping sustain higher intensity for longer.”

For broader comparisons, this is a good companion read: Acute vs Chronic Exercise Responses.

Final takeaway: make IB SEHS responses feel automatic

Acute physiological responses to exercise are your body’s instant upgrade system: pump more blood, move more air, and produce ATP faster. If you learn to explain each change with a clear “what, why, how,” you’ll write calmer, sharper IB SEHS answers under pressure.

To lock it in, revise the notes, then drill it under exam conditions using RevisionDojo’s Questionbank, Study Notes, Flashcards, AI Chat, Grading tools, Predicted Papers, Mock Exams, Coursework Library, and Tutors support -- all built to make IB SEHS feel manageable when it matters most.

IB SEHS goal setting in sport made simple: goal types, SMART targets, common mistakes, and exam-ready tips using RevisionDojo practice tools.