Rio Half Marathon fuel plan: carbs, fluid and sodium per hour.
August 15, 2027, Rio de Janeiro, Brazil. Set your finish time and the plan follows.
- Distance
- 21.098 km
- Climbing
- Not published
- Typical temperature
- 19 to 26 °C · 66 to 79 °F
- Aid stations
- See below
Your plan
Half marathon · 2 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 2014ACSM 2016+3 moreFluid an hour
To thirst
Without a sweat rate the research says drink to thirst. Do the sweat test to get a range.
NATA 2017ACSM 2007Sodium an hour
300 to 1,000mg
Nearer the top in the heat. A sweat sodium test gives you your own number.
Baker 2017NATA 2017+1 moreAbout 150 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.
See the prompt
I'm racing a Half marathon and expect to finish in 2 h. I haven't measured my sweat rate. Conditions look hot, 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 150 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.
Gemini, Grok Bot, Dots, Muse and Cue: copy the prompt and paste it in.
With Memory.fit, your AI would already know your sweat rate.
On Android now: get it on Google Play. One email when the iPhone app is on the App Store.
The course
What to know about Rio Half Marathon.
The 21K starts in Leblon at Av. Delfim Moreira and Rua Cupertino Durão and finishes at the Aterro do Flamengo, with an early start from 06:00. The organizer's 2027 page says the route is still to be confirmed; the 2026 route ran along Av. Vieira Souto and Av. Atlântica, through the Túnel Prefeito Marcello de Alencar and back to the Glória finish.
The organizer's 2027 page says there will be 12 stations on the course, without km or products. This is a separate August race from the June Maratona do Rio.
Race details checked November 9, 2026 from yescom.com.br, yescom.com.br, weatherspark.com. Courses and aid stations change: check the official page in race week.
Train for it
Train for Rio Half 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.
Questions
Rio Half Marathon: questions.
At a typical finish of 2 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.
Temperatures run from about 19 to 26 °C (66 to 79 °F): Average daily low and high in Rio de Janeiro in August (Weather Spark). Heat raises your sweat rate, so do a sweat test in similar weather.
The organizer's 2027 page says there will be 12 stations on the course, without km or products. This is a separate August race from the June Maratona do Rio. Check the athlete guide in race week, as positions can change.
More races
Fuel plans for races like this one.
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- Half marathonSemimaraton Iași fuel planApril 25, 2027 · Iași, Romania
- Half marathonUnited Airlines NYC Half fuel planMarch 21, 2027 · New York, United States
- Half marathonValencia Half Marathon Trinidad Alfonso fuel planOctober 24, 2027 · Valencia, Spain
Not medical advice. Memory.fit is not affiliated with Rio Half Marathon or its organizer.
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