💪 Sports Drink Electrolyte & Hydration Simulator

Exercise Begins — Baseline Hydration

A well-hydrated athlete starts with full fluid and electrolyte reserves.

• ~40 L: Total body water (roughly 60% of body mass)
• 140 mmol/L: Plasma sodium (normal serum concentration)
• 2–4 M: Active sweat glands (eccrine glands across skin)
• 5–7 mL/kg: Pre-hydration target (consumed hours before start)

Baseline stores

Body starts fully hydrated with normal electrolyte levels.

Sodium's role

Sodium retains water and drives fluid balance.

Pre-hydration habit

Athletes pre-load fluids before intense sessions.

Sweat Loss Accumulates

Exertion drives sweat output, carrying sodium and potassium out of the body.

• 200–2000 mg/L: Sweat sodium range (varies widely by athlete)
• 150–200 mg/L: Sweat potassium range (far lower than sodium)
• 0.5–2.5 L/hr: Sweat rate range (intensity and heat dependent)
• up to 2×: Salty sweater loss (genetic and acclimation driven)

Sweat composition

Sweat is hypotonic, mostly water with dissolved salts.

Sodium dominates

Sodium is lost far faster than potassium.

Individual variation

Salty sweaters lose two to three times more sodium.

Fluid Deficit Builds

Without matched replacement, water and electrolyte losses compound over the session.

• 2%: Performance threshold (body mass loss impairs output)
• >2%: Dehydration onset (thirst already lagging behind)
• 5–10%: Plasma volume drop (reduces cardiac stroke volume)
• +0.3°C: Core temp rise (per percent water lost)

Deficit accumulates

Losses outpace sips of plain water.

Performance drops

A two percent water loss slows endurance output.

Thirst lags

Thirst signals arrive after the deficit begins.

Sports Drink Formulated

Sodium, potassium, and carbohydrate concentrations are tuned to this athlete's losses.

• 500–700 mg/L: ACSM sodium range (general athlete recommendation)
• 6–8%: Carbohydrate target (optimal gastric emptying rate)
• 150–225 mg/L: Potassium range (replaces smaller sweat losses)
• 200–330 mOsm/kg: Osmolality target (isotonic to slightly hypotonic)

Matching sodium

Drink sodium is tuned to the athlete's sweat losses.

Adding carbohydrate

Carbohydrate concentration is set by exercise intensity.

Balancing osmolality

The mix stays isotonic for fast gastric emptying.

Optimal Rehydration

The matched formulation restores fluid and electrolyte balance efficiently.

• +40%: Fluid retention gain (vs plain water alone)
• 1.5 L / kg: Rehydration ratio (accounts for ongoing urine loss)
• ~60 g/hr: Carb oxidation rate (multiple transportable carb sources)
• 2–3%: Performance benefit (time-trial gain with matched drink)

Fluid returns

Sodium pulls water back into circulation quickly.

Electrolytes restored

Sodium and potassium stores return toward baseline.

Ready to continue

The athlete resumes exertion without cramping or fatigue.