Why do carbohydrates show up so often in IB SEHS pre-exercise nutrition questions?

Carbohydrates show up because they connect cleanly to performance through glycogen and blood glucose. In IB SEHS, you’re rewarded for explaining energy availability, not for naming “healthy foods.” Carbohydrate intake can increase muscle glycogen stores, which supports repeated high-intensity efforts and longer-duration exercise. It can also help maintain blood glucose, which matters when exercise lasts long enough for blood glucose to become a limiting factor. Examiners also like carbohydrates because they link naturally to fatigue: when carbohydrate availability drops, intensity often drops with it. A good answer will mention the activity type (endurance vs short sprint vs intermittent sport) and then explain the carbohydrate link accordingly.

What’s the IB SEHS explanation for eating too close to exercise?

The issue is not that eating close to exercise is “bad,” but that digestion and exercise compete for blood flow. In IB SEHS, you can describe that heavy meals close to exercise increase the risk of gastrointestinal discomfort because the stomach is still processing food. Foods high in fat and fibre can slow gastric emptying, which makes that discomfort more likely. If an athlete feels nauseous or cramped, their intensity and concentration can drop even if the food was nutritious. The key is timing and size: smaller, familiar snacks closer to exercise are usually better tolerated than large meals. In an exam, always link the timing choice to comfort and performance rather than personal preference.

How do I link hydration to thermoregulation in IB SEHS without sounding vague?

Start by naming the heat-loss mechanism: sweating and evaporation. Then explain what hydration changes: adequate body water supports sweat rate and helps maintain plasma volume. In IB SEHS, you can add that reduced plasma volume increases cardiovascular strain, because the heart has to work harder to maintain cardiac output. As dehydration worsens, sweat production can decrease, core temperature rises faster, and fatigue accelerates, especially in hot or humid environments. You don’t need exact numbers to score well, but you do need that chain: hydration -- sweat/evaporation -- core temperature control -- reduced strain -- better tolerance. If you want to practice this style, RevisionDojo’s Questionbank feedback is excellent at pointing out missing links.

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IB SEHS: Pre-Exercise Nutrition Explained | RevisionDojo

IB SEHS: Pre-Exercise Nutrition Explained

IB SEHS

RevisionDojo Team

•1/7/2026•6 min read

Pre-exercise nutrition is one of those IB SEHS topics that feels obvious until you try to explain it under exam pressure. You know you should “eat something,” but the real marks come from why it matters: energy availability, blood glucose stability, hydration status, and the simple fact that your gut is also an athlete.

In IB SEHS, pre-exercise nutrition isn’t about recovery or long-term adaptation. It’s about arriving at the start line (or the warm-up) with enough fuel and fluid to perform, delay fatigue, and stay mentally sharp.

Pre-exercise nutrition (IB SEHS) quick checklist

Use this as a fast IB SEHS plan for short-answer and extended responses:

Carbohydrates to support muscle glycogen and maintain blood glucose
Timing: larger meal earlier, smaller snack closer to exercise
Hydration to support thermoregulation and reduce cardiovascular strain
Low risk foods near exercise (avoid very fatty/high-fibre choices if you’re sensitive)

For the syllabus framing, start with IB SEHS A.2 Hydration and nutrition.

Why carbohydrates matter most in IB SEHS pre-exercise nutrition

Carbohydrates are the headline macronutrient before most training and competition because they top up muscle glycogen and help maintain blood glucose during exercise. In IB SEHS, that cause-and-effect chain is what you want to write: