SFuels ZONE 4 (prior SFuels RACE+) fueling drink mix is formulated for higher-intensity training and racing. SFuels ZONE 4 drink mix delivers multiple fueling substrates in one product to support consistent stable energy, rapid gut transit and gut resilience.

Zone 4 represents a higher-intensity training (and racing) zone, including the key metabolic inflection point – anaerobic threshold/functional threshold power (FTP). At this intensity the body is shifting its mix of fuel-substrates for energy. During half-full marathons and half-full long-course triathlons, athletes would spend most of their race-time between Zone 3 and Zone 4 intensities.
Through training and nutrition athletes begin to raise fat oxidation rates at progressively higher intensities. By this, athletes become more efficient at using fat and sparing muscle glycogen.  SFuels’ athlete lab data shows cases of tripling fat oxidation rates, while doubling power (watts/bike).  Sparing glycogen, through greater fat-oxidation (lower lactate production) supports stable consistent energy at race-pace intensities.

While optimizing fat-oxidation is key, training carbohydrate oxidation efficiency at Zone 4 race-intensities is also needed.  Key enzymes involved in the final metabolism of carbohydrates, need to also be trained during high-intensity workouts, in the same way we train fat-oxidation efficiency during Zone 2 workouts.  SFuels recommends supporting carbohydrate oxidation efficiency training during Zone 4 training and racing by using maltodextrin and Cyclic-Dextrin to support rapid gut transit, while avoiding (no Fructose) the risks of blunted training adaptions.

Additionally, SFuels ZONE 4 takes a 3-pronged approach to support Gut Resilience during High-Intensity training and racing. This includes –

1. A reduced carbohydrate dependency and intake will lower the known risks of high-carbohydrate consumption during endurance training/racing,
2. A gluten-free and sugar-alcohol-free formulation, SFuels Zone 4 drink mix minimizes the triggers known to add further risk of gut distress to training and racing. SFuels also excludes Fructose from its training products in avoiding Gut-membrane and aerobic adaptation de-training risks from day-to-day over-consumption of Fructose
3. SFuels Extended Substrate uses select MCT fatty acids and Glutamine which both fuel and provide nutrition to support Gut membrane integrity, which supports building Gut resilience during training.

Maintaining proper electrolyte balance is crucial for athletes, especially during extended periods of training and in hot or humid conditions. To offset the electrolyte loss that occurs through sweat, higher doses of sodium and potassium supplementation are often warranted.  Athletes who follow a lower carbohydrate protocol should supplement with electrolytes.  It’s important to consult with a healthcare provider or sports nutritionist to determine the appropriate electrolyte supplementation based on individual needs and training conditions.

SFuels ZONE 4 delivers 2X carbohydrate load, and 4X Glutamine per serve, compared to 1st generation SFuels RACE+ thanks to the dosage efficiency of SFuels Extended Substrate.