Fueling guide
Caffeine for endurance: what the research says
The International Society of Sports Nutrition position stand reports that caffeine at 3 to 6 mg per kilogram of body weight, taken about 60 minutes before exercise, improves performance in many studies.
The same stand says lower doses, around 2 mg per kg, may also work, and that response differs a lot between people.
Caffeine is a personal test. Your AI can keep a record of what you took and how the session went.
What the position stand says
The ISSN stand reviews trials of caffeine in endurance and other exercise. It describes a performance benefit for many athletes and notes effects that vary with genes, habit and sensitivity.
Higher doses did not add benefit in the stand, and they raised side effects such as jitters and poor sleep.
- Dose: 3 to 6 mg per kg of body weight.
- Timing: about 60 minutes before exercise.
- Possibly useful at about 2 mg per kg.
- Individual response varies: metabolism, habitual intake, sleep and anxiety sensitivity.
Doing the arithmetic
At 70 kg, 3 to 6 mg per kg is 210 to 420 mg. A cup of coffee or a gel varies in caffeine, so the label or a measured source matters.
Sleep after a late session is one reason the stand tells athletes to watch timing.
Testing in training
Because of the individual spread, the stand favors trying a dose in training before using it in a race. A record of dose, time and how it felt turns that into data.
In your AI
The AI you already use, with your data in Memory.fit.
- ChatGPTChatGPT plans your week, fuels your long sessions and writes it all back to Memory.fit.Set up ChatGPT
- ClaudeClaude writes your plans back to Memory.fit, and asks you before it replaces or removes something you have.Set up Claude
Grok BotGrok Bot plans and reviews from your real training, and can re-plan a week after a bad night's sleep.Set up Grok Bot
MuseMuse plans sessions from your real training and writes them into Memory.fit's Plan.Set up Muse
DotsOpenAI says a dot's background research uses your connected apps read only, so plans are written when you ask in the chat.Set up Dots- GeminiType @ in a Gemini chat and pick Memory.fit to ask about your training. Gemini asks you to allow each session it plans, and planning a whole week is not reliable yet.Set up Gemini
- GrokGrok reads your training, sleep and fuel, and can plan around them.Set up Grok
- Perplexity ComputerPerplexity Computer reads your training in Memory.fit. Whether it writes a plan back isn't checked yet.Set up Perplexity Computer
- Claude CodeClaude Code reads your training and writes the sessions it plans back to Memory.fit, asking before each change unless you allowed it.Set up Claude Code
CueYour Cue agents plan your week and write your fuel plans from your real training, sleep and recovery.Set up Cue
What to send
Copy one, send it to your AI.
“Look at my weight in Memory.fit and work out a caffeine range in mg from the ISSN position stand for my long run, then add it to my fuel plan.”
Tools:
get_athleteset_session_fuel_plan“Log the coffee I drank before this morning's ride in Memory.fit with its caffeine.”
Tools:
log_drink“Check my sleep in Memory.fit after the evening sessions where I took caffeine and tell me what you see.”
Tools:
get_sleepget_workouts“Save in Memory.fit that caffeine above one cup makes me jittery.”
Tools:
save_memory
Questions
In short.
The ISSN stand reports 3 to 6 mg per kg of body weight, about 60 minutes before exercise.
The stand says doses near 2 mg per kg may also be effective.
The stand lists genetics in caffeine metabolism, habitual intake, sleep sensitivity and anxiety sensitivity.
The stand does not show added benefit at higher doses, and side effects rise.
Because response varies so much, the stand's reasoning favors testing in training.
Sources · Checked November 10, 2026
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