Nutrition and hydration for performance (SACE Stage 2 Physical Education)
“Explain the role of carbohydrates, fats, proteins and fluids in fuelling performance and recovery, including pre-event, during-event and post-event strategies.”
Food and fluid are the fuel for movement. Carbohydrates are the main fuel for moderate and high intensity work, fats fuel low-intensity endurance, and protein repairs and builds muscle. Fluids prevent dehydration, which quickly harms performance. Smart timing matters: load carbohydrate and hydrate before an event, top up fuel and fluid during long events, and refuel with carbohydrate and protein plus rehydrate afterwards.
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What this dot point is asking
You must explain the roles of the major nutrients and fluids, and describe nutrition and hydration strategies before, during and after activity.
The fuel nutrients
- Carbohydrates are stored as glycogen in muscle and liver and are the dominant fuel for moderate to high intensity exercise. Glycogen stores are limited, so depletion is a major cause of endurance fatigue.
- Fats are an almost unlimited energy store and the main fuel at low intensities and rest, but they release energy slowly and need oxygen, so they cannot fuel high intensity work.
- Proteins are mainly for growth and repair of muscle tissue rather than fuel, contributing energy only when other stores run low.
At low intensity the body relies mostly on fats; as intensity rises toward the lactate inflection point it shifts to carbohydrate, which yields ATP faster per litre of oxygen. This is why carbohydrate availability limits high intensity endurance performance.
Hydration
Water regulates body temperature through sweating and maintains blood volume. Even mild dehydration (around 2 percent of body mass lost) raises heart rate, increases perceived effort and impairs performance and concentration. In long or hot events, electrolytes such as sodium are also lost in sweat and must be replaced.
Dehydration is a loss of body fluid that exceeds intake, reducing blood volume and the ability to sweat and cool. It causes a rise in heart rate and core temperature, earlier fatigue, and a decline in both physical and cognitive performance.
Nutrition and hydration strategies
Before the event.
- Eat a carbohydrate-rich meal a few hours before to top up glycogen.
- Endurance athletes may carbohydrate-load in the days before a long event to maximise glycogen stores.
- Hydrate well in the hours beforehand.
During the event.
- For events over about 60 to 90 minutes, take in carbohydrate (sports drinks, gels) to spare glycogen and maintain blood glucose.
- Drink fluids regularly to limit dehydration, with electrolytes for long or hot events.
After the event.
- Replace carbohydrate promptly to restore glycogen, which is slow and takes 24 to 48 hours.
- Include protein to support muscle repair.
- Rehydrate by replacing more than the fluid lost, with electrolytes to retain it.
Carbohydrate loading is a strategy of tapering training while increasing carbohydrate intake in the days before a long endurance event, super-compensating muscle glycogen stores so the athlete can sustain high intensity for longer before hitting the wall.
Linking nutrition to recovery and training
Nutrition is part of the recovery principle. Without adequate carbohydrate, glycogen does not restore between sessions and performance declines; without protein and rest, muscle does not repair and adapt. Good nutrition therefore enables the adaptations that training stimulates.
Because the optimal fuel mix depends on the intensity and duration of the event, nutrition strategy must be matched to the demands of the sport. A power athlete competing in short bursts relies less on glycogen sparing than a marathoner, who must defend limited stores across hours, while a team-sport athlete with intermittent high-intensity efforts needs carbohydrate availability and rehydration across a long match. The strongest answers do not just list nutrients but justify a timed plan for a specific athlete, explaining which fuel each strategy protects and how it links to the energy systems and the recovery the next session depends on.
Fuelling a marathon runner
A marathoner carbohydrate-loads in the three days before the race and hydrates well. They eat a carbohydrate-rich breakfast three hours before the start. During the race, which lasts over two hours, they take gels and sports drink to spare glycogen and replace fluid and electrolytes lost in sweat. Afterwards they consume carbohydrate and protein promptly to restore glycogen and repair muscle, and rehydrate with more fluid than they lost. Each step targets a specific fuel or fluid demand of the event.
Do not claim protein is the main energy source for exercise; carbohydrate and fat fuel almost all activity, and protein mainly repairs and builds tissue. Also avoid saying athletes should drink as much water as possible; over-drinking can dilute sodium dangerously, so fluid and electrolyte intake should match losses.
Assessment-style questions
Questions on this dot point, each with a worked answer, written by ExamExplained. Physical Education has no written exam, so use them to check your understanding before your assessment tasks.
Practice6 marksExplain pre-event, during-event and post-event nutrition and hydration strategies for an endurance athlete.Show worked answer →
A 6 mark task needs a strategy for each phase tied to a fuel or fluid demand.
Before. A carbohydrate-rich meal hours before tops up glycogen, with carbohydrate loading for long events and good hydration.
During. For events over about 60 to 90 minutes, take carbohydrate to spare glycogen and drink fluids with electrolytes in long or hot conditions.
After. Replace carbohydrate promptly to restore glycogen, include protein for repair and rehydrate with more than the fluid lost.
Markers reward each phase matched to its purpose rather than a general list of foods.
Practice4 marksExplain how dehydration affects performance and why over-drinking water can also be harmful.Show worked answer →
A 4 mark task needs the effects of dehydration and the over-drinking risk.
Dehydration. A loss of about 2 percent of body mass raises heart rate and core temperature, increases perceived effort and impairs physical and cognitive performance.
Over-drinking. Excess plain water can dilute blood sodium dangerously (hyponatraemia), so fluid and electrolyte intake should match losses.
Markers reward the specific dehydration effects and the balanced point that intake should match losses, not simply maximise water.
Practise this
Sources & how we know this
- Stage 2 Physical Education subject outline (2025 onwards) — SACE Board
- Stage 2 Physical Education: external assessment — SACE Board