The science
behind it.

• Topic 01

  In-race carbohydrates

  Protocol

  1.1–1.5 g/kg/h (≈ 60–120 g/h). Marathon ≥ 90 g/h in trained athletes; ultra up to 120 g/h using a 2:1 glucose:fructose blend to saturate SGLT1 + GLUT5.

  Why

  Above 60 g/h, glucose alone saturates the intestinal SGLT1 transporter. Adding fructose (via GLUT5) allows oxidation up to ~1.75 g/min without proportionally more GI distress.

  References

  • · Jeukendrup AE. Nutrition for endurance sports. J Sports Sci (2011)
  • · Podlogar T, et al. Carbohydrate intake during endurance exercise. Sports Med (2022)
  • · Viribay A, et al. 120 g/h CHO during marathon. Nutrients (2020)
• Topic 02

  Sodium & hydration

  Protocol

  Replace ~50% of sodium losses. Assumes average sweat sodium concentration of 800 mg/L. Sweat rate ≈ 1.5% of body mass per hour. Ceiling: 1500 mg/h.

  Why

  ACSM and the hyponatremia consensus (Hew-Butler) show partial (not full) replacement prevents both dehydration and dilutional hyponatremia. Above 1500 mg/h there is no extra benefit and GI distress rises.

  References

  • · Sawka MN, et al. ACSM Position Stand: Exercise and Fluid Replacement (2007)
  • · Hew-Butler T, et al. 3rd Intl. Exercise-Associated Hyponatremia Consensus. Clin J Sport Med (2015)
• Topic 03

  Caffeine

  Protocol

  3–6 mg/kg, 45–60 min pre-race (plasma peak at the gun). Additional doses via gel/Coke in the final third. Ergogenic ceiling: 6 mg/kg; above 9 mg/kg GI/CNS side effects rise without added benefit.

  Why

  Adenosine A1/A2A receptor antagonism reduces perceived effort and pain. The ISSN position stand confirms the 3–6 mg/kg ergogenic window in endurance.

  References

  • · Guest NS, et al. ISSN Position Stand: Caffeine and exercise performance. JISSN (2021)
  • · Spriet LL. Exercise and sport performance with low doses of caffeine. Sports Med (2014)
• Topic 04

  Sodium bicarbonate

  Protocol

  0.3 g/kg NaHCO₃ (≈ 1 serving Maurten Bicarb System), 60–90 min pre-race. Ceiling: 0.4 g/kg (GI risk rises sharply).

  Why

  Increases extracellular buffering capacity (HCO₃⁻), delaying muscle pH drop during high-lactate efforts (strongest effect in 1–10 min bouts, still relevant in marathon when finishing fast).

  References

  • · Carr AJ, et al. Effects of acute alkalosis on performance. Sports Med (2011)
  • · Saunders B, et al. Sodium bicarbonate: ergogenic effect. Eur J Sport Sci (2022)
  • · Maurten Bicarb System (Kipchoge / INEOS 1:59 protocol)
• Topic 05

  Dietary nitrate (beetroot)

  Protocol

  ~400 mg nitrate (≈ 1 Beet It Sport shot), 2–3 h pre-race. Chronic loading 3–7 days enhances the effect.

  Why

  The NO₃⁻ → NO₂⁻ → NO pathway boosts mitochondrial efficiency and lowers O₂ cost at submaximal intensity. Typical 1–3% improvement in running economy.

  References

  • · Jones AM. Dietary nitrate supplementation and exercise performance. Sports Med (2014)
  • · Dominguez R, et al. Effects of beetroot juice on endurance. Nutrients (2017)
• Topic 06

  Ultra-endurance: source rotation

  Protocol

  For efforts > 3 h alternate gel + drink + solid (banana, salted potato, soda). Average interval 20 min.

  Why

  Reduces flavor fatigue, spreads osmotic load across the gut, and mixes carb types (maltodextrin, sucrose, fructose) to sustain high oxidation without GI distress.

  References

  • · Costa RJS, et al. Gut training in endurance athletes. Eur J Sport Sci (2017)
  • · Tiller NB, et al. ISSN exercise & sports nutrition review: ultra-marathon. JISSN (2019)

Educational information · not medical advice