Nutrition, hydration, supplementation and sleep for performance: HSC Health and Movement Science Focus Area 2

A 4-mark response needs the effect, dose and suitable athlete for each, with the evidence status.

Caffeine

Around $3$ to $6$ mg/kg about 60 minutes pre-event; improves endurance and high-intensity performance and reduces perceived effort; suits most athletes subject to tolerance and sleep impact.

Creatine monohydrate

Around $3$ to $5$ g/day after a loading phase; benefits repeated high-intensity efforts and lean-mass gains; suits power, strength and team-sport athletes.

Evidence

Both sit in AIS Group A (well-evidenced).

Markers reward (1) effect, (2) dose, (3) suitable athlete, with the AIS Group A classification noted.

An 8-mark justify needs a named athlete and periodised plan across the three levers.

Choose an athlete

E.g. a marathon runner.

Nutrition

Periodise carbohydrate to load (around $3$ to $5$ g/kg on easy days, $6$ to $10$ g/kg on hard days), set protein at around $1.2$ to $2.0$ g/kg/day spread across meals.

Hydration

Start sessions euhydrated, replace around $400$ to $800$ mL/hour during, and around $125$ to $150\%$ of body-mass loss after, adding sodium for long or hot sessions.

Sleep

Protect $8$ to $9$ hours with a consistent schedule, the largest recovery lever.

Markers reward (1) a named athlete, (2) periodised carbohydrate and distributed protein, (3) hydration timing with sodium and a sleep target.

Range. About 5 to 7 g/kg body mass per day for a moderate training day.

Why matched to load. Carbohydrate refills muscle and liver glycogen, the dominant fuel for moderate-to-high-intensity work. Intake is periodised so that high-load days carry high carbohydrate availability (enough glycogen to fuel and to recover), while easy or rest days carry less so the athlete does not chronically over-fuel. Matching intake to demand supports both performance on hard days and body-composition / metabolic goals across the week.

Marking criteria: 1 mark for the correct range (about 5 to 7 g/kg/day); 1 mark for naming carbohydrate as glycogen fuel; 1 mark for the periodisation logic (high availability on hard days, lower on easy days). A bare "eat more carbs to have energy" with no range and no periodisation caps at 1.

Dehydration is a fluid deficit: too little fluid relative to sweat loss, raising heart rate at a set pace, raising perceived effort and core temperature, and impairing performance. Strategy: start euhydrated (pale-yellow urine; about 5 to 10 mL/kg in the 2 to 4 hours pre-exercise) and replace about 400 to 800 mL/hour during.

Exercise-associated hyponatraemia is the opposite imbalance: drinking large volumes of plain water without sodium during long events dilutes blood sodium dangerously low. Strategy: in long or hot events drink to thirst (not to a fixed large volume) and include sodium (e.g. a sports drink supplying about 20 to 30 mmol/L sodium).

Marking criteria: 1 mark for correctly defining dehydration (fluid deficit), 1 mark for correctly defining hyponatraemia (low blood sodium from over-drinking plain water), 1 mark for a valid dehydration strategy, 1 mark for a valid hyponatraemia strategy. Calling hyponatraemia "just dehydration" scores 0 for that side.

(a) Sweat loss. Body-mass change = 70.0 - 68.6 = 1.4 kg, which is about 1.4 L of fluid lost as sweat AFTER accounting for what was drunk. Total sweat loss = body-mass loss + fluid consumed = 1.4 + 0.6 = 2.0 L. (The 1.4 kg drop is the net deficit; the rider also replaced 0.6 L while sweating, so true sweat output was 2.0 L.)

(b) Replacement. The post-session guideline is to replace about 125 to 150 percent of body-mass loss. Using 150 percent of the 1.4 kg net loss: $1.4 \times 1.5 = 2.1$ L of fluid (with sodium) over the hours after the ride.

Marking criteria: (a) 1 mark for the 1.4 kg net body-mass change, 1 mark for adding the 0.6 L consumed to get 2.0 L true sweat loss. (b) 1 mark for using 150 percent of the 1.4 kg net loss, 1 mark for the answer of about 2.1 L with sodium noted. Replacing only 1.4 L (100 percent) misses the over-replacement rationale (sweat continues post-exercise).

(a) Relationship

Higher next-day carbohydrate intake is associated with higher restored muscle glycogen: 290 at 3 g/kg, 480 at 6 g/kg, 590 at 9 g/kg. The relationship is positive but NOT linear - it flattens (diminishing returns) at higher intakes.

(b) Why the gain shrinks

Going 3 to 6 g/kg adds 190 mmol/kg; going 6 to 9 g/kg adds only 110 mmol/kg. Muscle glycogen stores have a finite capacity, so as the muscle approaches saturation each extra gram of carbohydrate restores less glycogen. Beyond what the muscle can store, surplus carbohydrate is used for immediate energy or other fates rather than topping up glycogen.

(c) When 9 g/kg is justified

During very high training loads or carbohydrate loading for a long endurance event (e.g. the 24 to 48 hours before a marathon), where near-maximal glycogen stores genuinely improve endurance performance.

Marking criteria: (a) 1 mark for the positive trend WITH data, 1 mark for noting it is non-linear / diminishing. (b) 1 mark for quantifying the smaller increment (190 vs 110), 1 mark for the finite-storage / saturation reason. (c) 1 mark for a valid high-demand or carbo-loading context. Describing only "more carbs means more glycogen" with no diminishing-returns reading caps at 2.

Caffeine

AIS Group A (well-evidenced). About 3 to 6 mg/kg roughly 60 minutes pre-race improves high-intensity and endurance performance and lowers perceived effort - directly useful for a hard 1500 m. Caveats: individual tolerance, possible jitters / gut upset, and disrupted sleep if taken later in the day; dose should be trialled in training, not first used on race day.

Beetroot / nitrate

AIS Group A but with MODEST and more variable benefits, mainly improving exercise economy in submaximal/endurance efforts; the benefit for highly trained athletes and for a short, very intense 1500 m is smaller and less consistent than caffeine's.

Judgement

For a 1500 m runner, caffeine is the stronger, better-evidenced choice; beetroot is a reasonable, low-risk add-on but should not be relied on for a decisive gain. Both should be cleared with a dietitian and, where relevant, batch-tested. Neither substitutes for trained fitness, fuelling and sleep.

Marking criteria: 1 mark each for the correct evidence status and effect of caffeine and of beetroot (max 2); 1 mark for relating each to the 1500 m demand; 1 mark for a clear comparative JUDGEMENT (evaluate); 1 mark for a caveat (tolerance, batch-testing, or "trial in training"). A description with no judgement caps at 3.

This is a 12-mark extended response. Markers reward a sustained analysis (each lever linked by cause and effect to adaptation and performance), a named athlete with realistic figures, and the four levers integrated - not four separate lists.

Band 6 PLAN.

• Named athlete + thesis: a marathon runner. Training supplies the stimulus, but adaptation only happens in recovery; nutrition, hydration, supplementation and sleep are the four levers that determine how completely each session is absorbed, so they must be periodised to the training week, not treated as generic healthy living.
• Argument line 1 - Nutrition (refuel + repair): carbohydrate periodised to load (about 3 to 5 g/kg on easy days, 6 to 10 g/kg on hard days, with carbo-loading to about 8 to 12 g/kg pre-race) refills glycogen so the next quality session can be completed at intensity; protein at about 1.2 to 2.0 g/kg/day spread roughly 0.3 g/kg per meal drives the muscle protein synthesis that turns the aerobic stimulus into mitochondrial and capillary adaptation. Effect: sessions are fuelled AND the adaptive machinery is built.
• Argument line 2 - Hydration (protects the quality of the stimulus): starting euhydrated and replacing about 400 to 800 mL/hour with sodium keeps heart rate, perceived effort and thermoregulation in check, so the athlete actually hits the target intensity; post-session replacement of about 125 to 150 percent of body-mass loss restores readiness for the next day. Over-drinking plain water risks hyponatraemia, so sodium matters in long/hot sessions.
• Argument line 3 - Supplementation (a small, evidence-gated edge): AIS Group A aids such as caffeine (about 3 to 6 mg/kg) and, for repeated efforts, creatine are food-first additions cleared with a dietitian and batch-tested; they sharpen but never replace the work, fuelling and sleep.
• Argument line 4 - Sleep (the master recovery lever): protecting about 8 to 9 hours, consistently timed, is when growth-hormone release, muscle protein synthesis and CNS/skill consolidation occur - the biological window in which the stimulus becomes adaptation. Skimping here blunts every other lever.
• Synthesis: the four levers are interdependent - carbohydrate without sleep, or sleep without fuelling, leaves adaptation on the table - and all are periodised to the week so that the hardest sessions are the best supported. The performance payoff is a runner who completes more quality work, adapts more fully (higher VO2max, raised lactate threshold) and arrives at the race fully fuelled and rested.

Model paragraph (sleep line). Sleep is the lever that most directly converts the day's training into adaptation, because it is during deep sleep that growth-hormone secretion peaks and muscle protein synthesis and central-nervous-system recovery run hardest, while skill and pacing memories consolidate. For the marathon runner, protecting about 8 to 9 hours on a consistent schedule means each hard session is followed by the full biological window in which mitochondrial and capillary adaptation is laid down; cutting sleep to six hours leaves that window half-open, so the same training produces less adaptation, slower recovery and higher illness risk. This is also why sleep underwrites the other three levers - carbohydrate refuelling, protein-driven synthesis and any supplement edge all act through recovery processes that sleep governs - which is exactly why sports scientists call it the single largest, and most commonly under-used, recovery lever.

Marker's note: top-band answers (1) integrate all four levers rather than listing them, (2) sustain a stimulus to recovery to adaptation to performance chain, (3) anchor claims with specific figures (carbohydrate g/kg, fluid mL/hour, 8 to 9 hours sleep, caffeine 3 to 6 mg/kg) and a named athlete, and (4) keep answering the verb - ANALYSE means show how the parts interrelate to produce the outcome. Noting that the levers are interdependent and periodised to the training week, and gating supplements behind evidence (AIS Group A) and batch-testing, marks a precise response.