How many carbs per hour for Boston Marathon?

At a typical finish of 4 h, the research range is 60 to 90 g an hour, as glucose and fructose, set by how trained your gut is. Enter your own finish time above for your number.

What is the weather like at Boston Marathon?

Average daily low and high in Boston in April (Weather Spark). run from about 6 to 13 °C (43 to 55 °F). Heat raises your sweat rate, so do a sweat test in similar weather.

Where are the aid stations at Boston Marathon?

The organizer lists 26 aid stations; the table on this page has each one by km. Check the athlete guide in race week, as positions can change.

Marathon

Boston Marathon fuel plan: carbs, fluid and sodium per hour.

April 19, 2027, Boston, United States. Set your finish time and the plan follows.

Distance: 42.195 km
Climbing: Not published
Typical temperature: 6 to 13 °C · 43 to 55 °F
Aid stations: 26

Your plan

Marathon · 4 h

Carbs an hour

75g

The research range for this race is 60 to 90 g; your gut training sets where you start. Above 60 g, use glucose and fructose, about 2:1.

Jeukendrup 2014 Viribay 2020 +4 more

Fluid an hour

To thirst

Without a sweat rate the research says drink to thirst. Do the sweat test to get a range.

NATA 2017 ACSM 2007

Sodium an hour

300 to 1,000mg

Sweat sodium varies a lot between people. A sweat sodium test gives you your own number.

Baker 2017 NATA 2017 +1 more

About 300 g of carbs over the race. That is a 25 g gel every 20 minutes, or the same carbs from drink and chews.

Rehearse it in training first: the gut adapts in 2 to 4 weeks. Costa 2017

Hand it to your AI

Your AI can check these numbers against your training and adjust them. The prompt has your results filled in.

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I'm racing a Marathon and expect to finish in 4 h. I haven't measured my sweat rate. Conditions look cool, and my gut is in some training for fueling. A race fuel calculator built on the research (Jeukendrup 2014, the ACSM 2016 position stand) gave me: 75 g carbs an hour (glucose and fructose, about 2:1), about 300 g in total; fluid: drink to thirst, no sweat rate yet; 300 to 1,000 mg sodium an hour. Check this against my training and how my gut has handled fueling, then build my race day plan: what to take and when, with real products I can buy.

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Gemini, Grok Bot, Dots, Muse and Cue: copy the prompt and paste it in.

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With Memory.fit, your AI would already know your sweat rate.

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The course

What to know about Boston Marathon.

The historic course starts on Main Street in Hopkinton and follows Route 135 through Ashland, Framingham, Natick and Wellesley. It finishes on Boylston Street near the Boston Public Library in Copley Square.

On course: Poland Spring water, Gatorade Endurance Formula, Maurten Gel 100 and Gel 100 CAF 100. Train with what the course hands out, or carry your own.

Km	Leg	What's there
3.2	run	Poland Spring water, Gatorade Endurance Formula
4.8	run	Poland Spring water, Gatorade Endurance Formula
6.4	run	Poland Spring water, Gatorade Endurance Formula
8	run	Poland Spring water, Gatorade Endurance Formula
9.7	run	Poland Spring water, Gatorade Endurance Formula
11.3	run	Poland Spring water, Gatorade Endurance Formula
12.9	run	Poland Spring water, Gatorade Endurance Formula
14.5	run	Poland Spring water, Gatorade Endurance Formula
16.1	run	Poland Spring water, Gatorade Endurance Formula
17.7	run	Poland Spring water, Gatorade Endurance Formula
19	run	Maurten Hydrogel Depot: Gel 100 and Gel 100 CAF 100 (Wellesley town line)
19.3	run	Poland Spring water, Gatorade Endurance Formula
20.9	run	Poland Spring water, Gatorade Endurance Formula
22.5	run	Poland Spring water, Gatorade Endurance Formula
24.1	run	Poland Spring water, Gatorade Endurance Formula
25.7	run	Poland Spring water, Gatorade Endurance Formula
27.4	run	Poland Spring water, Gatorade Endurance Formula, Maurten Gel 100 and Gel 100 CAF 100 (Newton)
29	run	Poland Spring water, Gatorade Endurance Formula
30.6	run	Poland Spring water, Gatorade Endurance Formula
32.2	run	Poland Spring water, Gatorade Endurance Formula
33.8	run	Poland Spring water, Gatorade Endurance Formula
34.6	run	Maurten Hydrogel Depot: Gel 100 and Gel 100 CAF 100 (just after Boston College)
35.4	run	Poland Spring water, Gatorade Endurance Formula
37	run	Poland Spring water, Gatorade Endurance Formula
38.6	run	Poland Spring water, Gatorade Endurance Formula
40.2	run	Poland Spring water, Gatorade Endurance Formula

Race details checked October 17, 2026 from baa.org, baa.org, baa.org, baa.org, weatherspark.com. Courses and aid stations change: check the official page in race week.

Train for it

Train for Boston Marathon with your AI.

With Memory.fit, your AI reads your real training, sleep and fuel, plans your weeks toward race day and shows the plan in the app.

Build a prompt for your AI

Questions

Boston Marathon: questions.

At a typical finish of 4 h, the research range is 60 to 90 g an hour, as glucose and fructose, set by how trained your gut is. Enter your own finish time above for your number.
Average daily low and high in Boston in April (Weather Spark). run from about 6 to 13 °C (43 to 55 °F). Heat raises your sweat rate, so do a sweat test in similar weather.
The organizer lists 26 aid stations; the table on this page has each one by km. Check the athlete guide in race week, as positions can change.

Not medical advice. Memory.fit is not affiliated with Boston Marathon or its organizer.

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