Caffeine is one of the most studied ergogenic aids in sport (AIS Group A). The performance lift is real, but the dose-response curve is individual and the window is tight. Too little and you under-dose; too much and you cramp, get jittery, or sleep five hours before a 5 AM start.
This tool generates your pre-race acute dose, your mid-race top-up schedule, and an optional 3-day or 7-day race-week taper so habitual coffee drinkers restore receptor sensitivity before the gun. Inputs are calibrated to body weight, habitual intake, sensitivity, and the time the race actually starts.
Caffeine Timing
Pre-race dose, mid-race top-ups, and race-week taper protocol. AIS Group A evidence tier.
Not Medical Or Nutrition Advice
This calculator and the resulting plan are educational only. Endurance sports carry inherent risks and individual nutrition needs vary. Athletes should consult a qualified healthcare professional or a registered sports dietitian before applying any nutrition, hydration, or supplementation strategy, especially if you have a medical condition, are pregnant, take medications, or are training through injury. Use this information at your own risk.
Methodology + Citations
Pre-race acute dose is calibrated by body weight (3 to 6 mg/kg, per the AIS Sports Supplement Framework and the ISSN Position Stand on caffeine and exercise performance, Guest 2021). Habitual high users default to the upper end because chronic intake shifts adenosine receptor density.
Sensitivity modifier reflects the well-documented inter-individual variation in CYP1A2 (Pickering & Kiely 2018). Self-reported jitter at moderate doses is a reasonable field proxy for slow-metabolizer status.
Mid-race top-ups (1.0 to 1.5 mg/kg/hr starting after hour 1.5 to 2.5) replace caffeine cleared during the early portion of the race. Plasma half-life of caffeine is 5-6 hours, so even a single pre-race dose maintains meaningful blood levels for a marathon-length effort.
The 3-day taper protocol is the conservative option supported by Bell & McLellan (2002): partial withdrawal across 72 hours produces measurable improvement in acute caffeine response without the full withdrawal symptom burden of a 7-day protocol.
Sources: Guest NS et al. (2021), Burke LM (2008), Pickering & Kiely (2018), Bell & McLellan (2002), AIS Sports Supplement Framework. Always test caffeine strategies in training before race day.
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