Build Your Hydration & Fuelling Profile

A four-step guided system that builds your precise fluid, sodium, carbohydrate, and capsule strategy — for training or racing.

Physiology

Your body is the starting point. These inputs calibrate every calculation that follows — the same way a sports scientist would begin your assessment.

Body Weight Used to scale sweat volume estimates and total fluid requirements to your body mass.

70kg

4070100130

Sex optional Biological sex influences average sweat rate at a given body weight. Males tend to produce higher absolute sweat volumes due to greater muscle mass.

Age optional Thermoregulatory efficiency declines with age. Masters athletes (50+) tend to have a lower sweat onset threshold and reduced peak sweat rate.

35yrs

1632486480

Training Level More experienced athletes often produce higher sweat volumes due to earlier onset of sweating and greater thermoregulatory efficiency.

Gut Sensitivity During Exercise Athletes with a sensitive gut may need to moderate carbohydrate intake rates. We use this to adjust your upper fuelling limit.

Heat Acclimation Status True heat acclimation requires sustained, repeated heat exposure that raises core temperature — not just living somewhere warm or having trained outdoors recently. Be honest with yourself: under-claiming is safer than over-claiming, because acclimated athletes lose less sodium per litre of sweat and need less replacement.

Environment

Conditions are one of the biggest drivers of sweat rate. A 10°C rise in temperature can increase fluid losses by 30–50% — whether you're training or competing.

Air Temperature The primary environmental driver of sweat rate. Applied as a multiplier to your baseline fluid requirements.

20°C

5°15°25°35°45°

Humidity High humidity reduces sweat evaporation, so your body sweats more to achieve the same cooling. This increases total fluid loss.

Training or Racing Setting Indoor sessions remove the benefit of wind cooling and often run warmer than outdoor conditions, raising effective thermal load.

Sun Exposure Direct sun adds 3–8°C to effective thermal load, increasing sweat rate beyond what air temperature alone suggests.

Sweat & Sodium Profile

Sweat rate and sodium concentration are the two most individualised hydration variables. Select the profiles that best describe you — or enter your sweat test data for precision.

Sweat Profile How much you sweat determines how much fluid you need to replace each hour. Athletes range from 0.5 L to over 2.5 L per hour.

Sodium Loss Profile Sweat sodium varies up to 4× between people, and most athletes overestimate it — under-claiming is safer, so default to Low or Moderate if unsure. The strongest signs of High Salt Loss: cramping in heat despite drinking enough fluid; a measured sweat test above ~1,200 mg/L; or assessment by a coach or sports-medicine professional. Visible salt marks alone are common and don't necessarily mean high loss. If you've had a measured sweat test, use the panel below.

Cramping History Frequent cramping in heat or long sessions is a strong indicator of high sodium loss. If you cramp regularly, we use this to sense-check your sodium profile.

Entering your sweat test data overrides the preset selections above and significantly improves accuracy.

Measured Sweat Rate Weigh yourself before and after a 1-hour session with no fluid intake. 1 kg weight loss ≈ 1 L sweat.

L / hr

Sweat Sodium Concentration Obtained via a sweat test (e.g. Precision Hydration). If unsure, leave blank and use the preset above.

mg / L

Session Details

Tell us about your session — whether you're heading out for a training block or toeing the start line. Duration and intensity determine your carbohydrate and total fluid targets.

Session Type Competitive sessions typically call for higher carbohydrate intake and more precise sodium management than training.

Sport or Discipline Different sports have different metabolic demands and practical fuelling constraints. Triathlon generates a specific segment-by-segment breakdown.

Triathlon Format Format determines approximate split durations used to calculate per-discipline fluid, sodium, and capsule targets.

Session Duration Total duration determines cumulative fluid, sodium, and carbohydrate requirements. Carbohydrate needs increase beyond 75–90 minutes.

30m2hr4hr8hr17hr

Effort Level Higher intensity increases carbohydrate oxidation and metabolic heat production, raising both fuel and fluid demands.

Hydration Setup If your drink already contains sodium, we subtract that from your capsule requirement so you're not doubling up.

On the run, what will you drink? The bike drink isn't on the run course — triathletes run on what aid stations carry (IRONMAN-series races now serve Precision PH 1000) or what they carry themselves. Pick the run drink so we credit it on the run instead of assuming your bike drink is there. We count it at ~65% of its bike-leg rate, since you drink less from cups than from a bottle. Capsules top up the rest.

RUN DRINK — CREDITED AT ~65% ON THE RUN

Not sure what your race carries? Confirm before race day. If it's water only, choose that — you'll carry the full sodium as capsules.

Fluid Access During Session Knowing your resupply frequency lets us translate hourly targets into practical carry volumes and stop strategies.

Targets above 60 g/hr carbs or 1,500 mg/hr sodium require gut adaptation built over weeks. If this is new to you, start at the lower end and build up across training sessions before applying these numbers to a key event.

05 — Your Strategy

Race-day briefing.

A complete protocol built from your physiology, conditions, and session demands. Before, during, and after — every dose with a time on it.

High confidence

Session

Your strategy is ready — enter your email to unlock.

We'll send your complete hydration and fuelling plan to your inbox — pre-session loading, hour-by-hour execution, post-session recovery.

Full Protocol view with Pre / In / Post phases
Capsule cadence and timing protocol
Calculation transparency with confidence rating

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◆ Sodium covered by drink

Resend

Email me the plan again

Didn't receive your plan, or want a fresh copy after updating your inputs? Send it to your inbox again.

Coach

Send to your coach

Open your mail app with the full plan pre-formatted, ready to send to your coach for review.

Social

Share your plan

Copy a shareable summary you can post to Strava, Instagram, or send to a training partner.

Recalculate

Update your protocol

Change session conditions, sweat profile, or drink setup to see a new protocol.

Lytework Sodium Capsules

Built for this protocol. See the capsules.

345 mg precision-dosed sodium per capsule. No sugar, no flavour, no guessing. The format the Hydration Intelligence System is built around — dosed to your individual targets, taken with any fluid.

See the capsules Visit the Lab

Important — Read before use

The Lytework Hydration Intelligence System is an experimental decision-support tool. It is not medical advice. Outputs are derived from published sports-science models and your self-reported inputs. Validate against sweat testing and consult a sports-medicine professional or qualified coach before relying on this protocol for key sessions, particularly in extreme heat, at high intake volumes, or if you have a medical condition affecting fluid or electrolyte balance.

Lytework Labs — Hydration Intelligence System v3.1 · Updated continuously based on field data and peer-reviewed sports-science literature.

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