| Metric | Value | Copy |
|---|---|---|
| Duration | {{ duration_hm }} | |
| Carbs (g/h) | {{ carb_target_gph }} | |
| Total carbs (g) | {{ Math.round(total_carb_g) }} | |
| Fluid (L/h) | {{ fluid_lph_display }} | |
| Total fluid (L) | {{ fluid_total_l_display }} | |
| Drink concentration (g/L) | {{ Math.round(drink_carb_g_per_l) }} | |
| Drink carbs (g/h) | {{ Math.round(drink_carb_gph) }} | |
| Solids carbs (g/h) | {{ Math.round(solids_carb_gph) }} | |
| Gels per hour | {{ gels_per_h_display }} | |
| Bottles per hour | {{ bottles_per_h_display }} | |
| Sodium target (mg/h) | {{ Math.round(sodium_target_mgh) }} | |
| Sodium from drink (mg/h) | {{ Math.round(drink_sodium_mgh) }} | |
| Sodium from gels (mg/h) | {{ Math.round(gel_sodium_mgh) }} | |
| Sodium shortfall (mg/h) | {{ Math.round(sodium_shortfall_mgh) }} | |
| Salt caps per hour | {{ salt_caps_per_h_display }} | |
| Totals: gels / bottles | {{ gels_total_display }} · {{ bottles_total_display }} |
| # | Window | Carbs (g) | Drink (mL) | Sodium (mg) | Copy |
|---|---|---|---|---|---|
| {{ r.idx }} | {{ r.time }} | {{ r.carb_g }} | {{ r.drink_ml }} | {{ r.sodium_mg }} | |
| No timeline yet. | |||||
Endurance nutrition usually breaks down at the point where broad advice has to become a real bottle plan. A target like 75 or 90 grams of carbohydrate per hour sounds simple until you also need to account for fluid loss, drink concentration, sodium, bottle size, and how often you can realistically eat or drink while moving.
This planner turns that tangle into one coordinated session plan for running or cycling. You enter duration, body weight, effort zone, carbohydrate goal, drink mix, bottle size, gel nutrition, and optional sweat data. The result is a clear set of hourly targets, full-session totals, bottle and gel counts, sodium coverage, and time windows you can actually follow.
That makes it useful for long training days, race rehearsals, hot-weather sessions, and aid-station planning. Instead of asking only “How many carbs should I take?”, you can check whether the same plan also demands too many bottles, leaves a sodium gap, or asks for a gel rhythm you already know your stomach dislikes.
The tool is best used as a planning baseline, not as proof that one exact intake rate is correct for every athlete. Sports nutrition guidance gives useful ranges, but sweat rate, sweat sodium, gut tolerance, course support, and weather vary widely. When you have measured data, enter it. When you do not, use the estimates to frame the next training test rather than treating them as a fixed prescription.
The planner links three streams that athletes often think about separately: carbohydrate delivery, fluid replacement, and sodium replacement. They are connected here on purpose. When fluid demand rises, drink-based carbohydrate rises with it if your bottle concentration stays the same. The same fluid estimate also changes sodium loss, bottle turnover, and the size of any capsule gap.
If you enter a measured sweat rate, that value drives the hydration side of the plan. If you leave it at zero, the tool estimates fluid needs from temperature, humidity, sport, effort zone, and body weight, then clamps the result to a practical range of 0.25 to 2.5 liters per hour. Running and cycling are handled as different contexts within that estimate, and the same is true for easy versus very hard sessions.
| Output | How the tool derives it | Why it matters |
|---|---|---|
| Fluid target | Measured sweat rate overrides the estimate. Otherwise the tool models fluid needs from temperature, humidity, sport, effort zone, and body weight. | Drives bottle count and also changes how many drink carbs and drink sodium you get each hour. |
| Drink carbs | Hourly fluid target multiplied by drink carbohydrate concentration in grams per liter. | Shows how much of the carb goal your bottle plan already covers before gels or other solids are added. |
| Solid carb gap | The remaining difference between carb target and drink carbs, converted into gels per hour if a gel carb value is present. | Turns an abstract fueling target into a practical carrying and tolerance question. |
| Sodium target | Estimated at 70% of hourly sodium loss, using either manual sweat sodium or one of the built-in profiles: low 300, medium 600, high 900, or very high 1200 mg/L. | Makes clear that the tool is planning partial replacement rather than assuming that every milligram lost must be replaced during the session. |
| Salt capsule need | Any sodium still missing after drink and gel sodium are counted is divided by the salt-cap dose you entered. | Shows whether capsules are filling a real shortfall or only duplicating sodium already present in your bottles and gels. |
| Fueling timeline | The session is split into repeated windows from 5 to 180 minutes, with each window receiving a share of carbs, drink volume, sodium, and gels. | Converts hourly math into something you can tape to a top tube, save for race notes, or compare across rehearsals. |
| Session length | Common sports nutrition context | How to use that context in this planner |
|---|---|---|
| Under about 45 minutes | During-exercise carbohydrate is often unnecessary for performance. | The planner is still useful if you want to rehearse bottle setup, but the timed feeding schedule matters less than hydration comfort. |
| About 1 to 2.5 hours | Many position statements use roughly 30 to 60 g/h as a common intake range. | Check whether your drink alone gets you near that range or whether the plan depends on frequent gel use. |
| Longer than about 2.5 to 3 hours | Up to 90 g/h is often discussed for longer events when the athlete has trained tolerance and absorption. | Use the charts and totals to see whether that target stays realistic once bottles, sodium, and carrying limits are added back into the picture. |
The outputs are then available as a metrics table, a timed fueling table, two bar-style planning charts, a duration-versus-carbohydrate map, and a JSON summary. Copy, CSV download, DOCX export, and chart-image export all stay on the device because the planner has no tool-specific server processing path.
The most useful starting point is not the sodium tab or the chart map. It is the relationship between your carb target, drink mix, and fluid target. If the drink already supplies most of the carbohydrate, the plan may become easier to follow even if the bottle turnover is high. If the drink supplies very little, the tool will show a larger gel or solid-food gap, which may be fine for some athletes and a bad idea for others.
That is why session duration matters. A target of 60 grams per hour may be gentle enough for a two-hour ride but can still add up to a large total over five or six hours. A target of 90 grams per hour may sit well inside current endurance guidance for longer events, yet the practical question is whether your gut, aid stations, and carrying setup can support it. The planner helps with that second question.
Hydration should be handled with the same realism. If you know your sweat rate from before-and-after weigh-ins in similar conditions, use it. If you do not, the estimate gives you a starting point, but it is still only a model. Large differences in body size, heat acclimation, clothing, pace, and weather can move real-world sweat loss far away from a default estimate, especially in heat or humidity.
Sodium works best when treated as part of hydration, not as a separate miracle fix. The planner already counts the sodium coming from drink mix and gels before it shows any shortfall. That often reveals that a bottle plan is doing more of the work than expected. In other cases it shows the opposite: a hot session with a high sweat-sodium profile may create a sodium gap that is much harder to close than the carbohydrate gap.
A good decision flow is simple. Pick a realistic carbohydrate goal for the session. Enter the drink you actually use. Add measured sweat data if you have it. Then ask whether the resulting bottle count, gel count, and sodium gap still look realistic for the route, event support, and stomach tolerance you will have on the day.
The headline summary is most useful when read as a connected set. A plan that looks strong from a carbohydrate standpoint may still be awkward if it requires more than two standard bottles per hour. A plan with modest bottle turnover may still be difficult if the gel count becomes high enough to irritate the stomach or create aid-station dependence.
The sodium numbers need similar context. In this tool, the sodium target is a planning target based on 70% of estimated hourly sodium loss, not a claim that every session demands exact sodium replacement. If the drink and gels already cover the target, the zero shortfall is often the most important number on the screen because it tells you extra capsules may be unnecessary.
The timeline is deliberately more concrete than the summary. Each row breaks the session into repeatable windows so you can see what one 20-minute, 30-minute, or 45-minute block really asks of you. Because the rows are evenly distributed from hourly values, fractional gels and partial bottles will appear. That is expected. They are pacing cues, not a literal instruction to tear a packet in half every time.
The chart tabs give three different planning views. Carb Targets compares drink intake, gel intake, and the full target both per hour and across the full session. Hydration Plan turns the same plan into milliliters per hour, bottles per hour, and total liters. Fueling Strategy Map places the current duration and carbohydrate target against the tool’s own built-in guidance line and conservative, endurance, and aggressive bands.
The planner also raises a limiting note when values become more demanding. It flags high fluid targets at 1.5 liters per hour or more, high carbohydrate targets above 110 grams per hour, and high sodium targets above 1200 milligrams per hour. Those labels are not medical warnings, but they are useful prompts to slow down and ask whether the plan is truly tested.
A two-hour run at zone 3 with the default setup uses a 90 g/h carb target, a 60 g/L drink, 500 mL bottles, 25 g gels, 20 °C weather, 50% humidity, and the medium sodium profile. Because no measured sweat rate is entered, the tool estimates fluid needs at about 0.83 L/h.
At that fluid rate, the drink contributes about 49.6 g/h of carbohydrate. The remaining gap is about 40.4 g/h, which turns into roughly 1.62 gels per hour at 25 grams each. Bottle turnover lands near 1.65 bottles per hour, which works out to a little over three 500 mL bottles across the full run.
The modeled sodium target is about 347 mg/h, but the entered drink and gels already provide more than that, so the sodium shortfall falls to zero and the capsule line also stays at zero. On a 30-minute timeline, the plan asks for about 45 grams of carbohydrate, 410 mL of drink, 170 mg of sodium, and about one gel per block.
Now switch to a three-hour run at zone 4 in 26 °C and 65% humidity, keep the bottle size at 500 mL, set drink carbs to 50 g/L, and choose the very high sodium profile. The planner estimates fluid needs at about 1.33 L/h, which already tells you the day may be limited more by fluid logistics than by carbohydrate math.
That bottle plan supplies about 66.3 g/h of carbohydrate, so a 70 g/h target leaves only a small gel gap. Sodium is different. The same session produces a modeled sodium target near 1114 mg/h, while drink and gels together cover only about 405 mg/h. With a 200 mg salt capsule, the remaining shortfall works out to roughly 3.55 capsules per hour.
This is exactly the kind of case where the planner is useful. It shows that the carb target itself may be workable, but the broader plan may not be. You might need larger bottles, different sodium concentration, measured sweat testing, or a less aggressive sodium assumption before the setup makes sense in the real world.
Yes. If you enter a sweat rate above zero, the planner uses that value instead of its weather-and-effort estimate. That is the better choice whenever the number comes from repeated testing in similar conditions.
No. Within this planner, the sodium target is set at 70% of estimated hourly sodium loss. That makes it a structured session-planning target, not a claim that every athlete should replace all sodium lost in sweat during exercise.
The plan still builds. Blank or zero values simply remove that contribution stream. For example, if gel carbohydrate is zero, the summary can still show an unmet solid-carb gap even though gels per hour stays at zero because no per-gel carbohydrate amount is available.
The tool spreads hourly targets evenly across the timeline windows and then rounds them for display. Fractions are there to help pace intake. They are not telling you that every step of the session must be handled as a perfectly even physical split.
Yes. The results panel appears whenever duration is greater than zero. Missing nutrition values usually reduce the related output instead of blocking the calculation, so it is worth checking the summary for zeros before you trust the plan.
No. The planner’s calculations, table copies, chart downloads, document exports, and JSON export run in the browser for this tool.