Fuel timing in brick workouts is less about a single rule and more about a systematic exploration of how your body responds when you combine bike effort with running. Start with a baseline: perform a bike-run session at a steady, sustainable power or pace, and use a simple carbohydrate source you tolerate well. Track how your stomach feels, how your energy dips, and whether you crave salt or sweetness. Then adjust timing by trialing fueling at different points, such as 15, 30, or 45 minutes into the bike, and observe the run transition for any signs of fatigue or GI upset. Record your observations to build a personalized fueling map for race week.
The goal of brick fueling practice is to reveal the exact moment when you switch from bike energy to run energy most cleanly. Many athletes discover that consuming carbs too early blunts appetite for the run, while waiting too long triggers a sudden energy drop. A practical approach is to use a consistent calorie amount across sessions, but vary the timing window. Include electrolytes if you tend to sweat heavily. Pay attention to hydration cues, and note any thirst, bloating, or cramping. Your notes will guide you toward a rhythm that minimizes surprises on race day.
Timing experiments should be a controlled, progressive process.
Begin with a conservative fueling plan that matches your body size and training load, then build complexity across sessions. For example, consume 60 grams of carbohydrate per hour during the bike segment and experiment with timing adjustments in 10-minute increments. After you dismount, observe how smoothly you transition to running without abrupt GI distress or energy crashes. Use real-food options or traditional gels based on what your stomach tolerates during training. Don’t switch to new products in the week before a race; the brick sessions are for dialing in the routine, not rediscovering tolerance.
In later brick sessions, introduce varied carbohydrate sources to test compatibility with your gut. Some athletes perform better with a steady stream of gels, others with small bites of energy chews or a soft, portable bar. The key is consistent intake while maintaining a comfortable pace. Track sensations like fullness, belching, or nausea, and correlate them with run pace. If you notice a slowdown or sour stomach at a certain time after dismount, adjust the timing or composition for the next session. This iterative process builds confidence for race morning.
Translate brick data into a practical, race-ready plan.
Structure brick workouts as a sequence of controlled trials rather than random experiments. Start with one variable changed at a time—either the start time of nutrition, the rate of intake, or the carbohydrate type—while keeping all other factors constant. Use a consistent run distance and effort level so you can compare results meaningfully. After each session, review how your body responded: run pace, perceived exertion, GI symptoms, and overall energy. Over several weeks, you’ll identify a narrow window that consistently feels tolerable and sustainable for the bike-to-run transition.
Build a simple scoring system to assess each trial. For example, assign points for ease of transition, absence of GI distress, and ability to maintain target run pace. Weight data like heart rate and cadence to understand how fueling timing interacts with physiological stress. If a trial produces headaches, cramps, or a heavy stomach, it signals a need to revert to a previous approach or refine the timing. The aim is to catalog a reliable plan that you can implement without overthinking on race day.
Use consistent, documented practice to lock in tolerance.
After several cycles of testing, you should begin to see a clear preference for a particular timing window. Translate this into a concise race-day plan that aligns with your warm-up, bike cadence, and anticipated run pace. Outline the exact nutrition products, the hourly rate, and the precise times to initiate intake. Make sure your plan accommodates course profile and weather conditions, which can alter gastric comfort. Practice the final plan in a long brick to confirm it holds under real fatigue and heat stress. Your confidence will grow as trivial changes to timing yield consistent, predictable energy.
A practical tip is to map fueling to your cadence cues rather than to the clock. For instance, if you notice you feel strongest at a certain cadence during the bike, time your intake to finish about five minutes before you plan to increase your cadence for the run. This approach keeps your mouth from drying out and reduces the chance of cramping. Additionally, rehearse nutrition changes on days with simulated race-day heat to ensure sweat losses and electrolyte needs are accounted for in your timing strategy.
Build a sustainable, confidence-boosting fueling approach.
Never underestimate the value of consistent practice in brick sessions. Repetition consolidates the relationship between fueling timing and perceived effort, which translates into calm, reliable decisions during the race. Maintain a log with date, weather, body weight, stomach comfort, run pace, and energy level. Include a rating for overall tolerance and a note about environmental factors such as humidity or wind. Over weeks, you’ll notice patterns that guide you toward a stable, tolerable plan that supports a strong run off the bike.
It’s also important to simulate race-day contingencies during brick workouts. Practice what happens if you miss a planned fueling window or encounter a momentary GI upset. Try a quick adjustment that keeps energy flowing without derailing your rhythm. By rehearsing these small contingencies, you’ll become adept at adapting on the fly while preserving your overall strategy. The goal is resilience, not rigidity, when the course throws a curveball.
A sustainable approach balances practicality with physiological response. Favor familiar products and flavors to reduce cognitive load during the race, and aim for a steady energy supply rather than spikes. Consider your body size, training volume, and the run distance when calculating hourly carbohydrate targets. Hydration must align with electrolyte needs, especially in heat. Your brick data should emphasize comfort, not discomfort. When a plan remains consistently tolerable across several sessions, you’ve likely found your most tolerable race-day strategy.
Finally, integrate your brick insights into a race-day ritual that feels natural. Develop a pre-race checklist that confirms your planned timing, product selection, and dose. Practice the entire sequence in a simulated taper week, then translate the routine to race morning with a calm, repeatable cadence. A well-practiced fueling timing strategy reduces anxiety, enhances digestion, and allows you to run with sustained energy. The most effective plan is the one you can deliver under pressure with minimal cognitive effort.
