Sports Medicine Weekly outlines updated duration-based carbohydrate targets and gut training strategies for ambitious endurance athletes over 35.
In August 2026, Sports Medicine Weekly released an in-depth audio segment outlining updated guidelines for carbohydrate intake during endurance exercise. The presentation framed endurance fueling as a strict duration-based strategy rather than a single universal target. A related announcement from the University of Birmingham detailed the exact same broad framework. Both resources emphasize adjusting intake targets based on the specific length of your event and practicing that strategy progressively.
Endurance competitors often face confusion over exactly how much they should eat during long sessions. These updated targets aim to replace that guesswork with reliable methodology. The segment reflects a major shift away from simple reactionary fueling approaches. Athletes are now encouraged to plan their carbohydrate intake well before fatigue sets in.
The new framework clearly defines optimal ranges for efforts lasting anywhere from under an hour to ultra-distance events. This refined guidance offers a highly practical roadmap for athletes wanting to maximize their training adaptations.
The central conclusion from the new segment is that you must match your carbohydrate intake to your session length. Athletes exercising for less than 45 minutes generally do not need any carbohydrate intake. For these very short efforts, a simple carbohydrate mouth rinse may provide a potential benefit without requiring digestion. For sessions lasting 45 to 75 minutes, the segment describes small amounts of carbohydrate or a mouth rinse as valid options.
For sessions lasting one to two hours, the segment recommends approximately 30 to 60 grams of carbohydrate per hour. Athletes who are new to fueling should generally begin at the lower end of this range. You should always assess your personal tolerance before attempting to increase your hourly intake. Efforts lasting two to three hours shift the recommendation to approximately 60 grams per hour.
When your exercise extends beyond two and a half hours, you may justify up to 90 grams per hour. Achieving this higher intake requires a specific combination of glucose and fructose. The article notes that more recent research suggests some well-trained athletes may tolerate as much as 120 grams per hour during very long events. However, 90 grams per hour remains the primary upper target in the official duration-based table for most athletes.
The physiological reason for these specific limits comes down to intestinal transport pathways. Your body cannot simply absorb an unlimited amount of sugar at one time. The segment identifies SGLT1 as the transporter used exclusively for glucose, which reaches a practical ceiling at roughly 60 grams per hour. Fructose relies on an entirely different transporter called GLUT5.
Utilizing both pathways simultaneously is the key to achieving higher absorption rates safely. Combining glucose with fructose can increase total carbohydrate oxidation compared with using glucose alone. A combined-carbohydrate drink can raise oxidation from approximately 1 gram per minute with a single source to roughly 1.3 grams per minute. This physiological mechanism is why older endurance athletes must carefully check the ingredient labels on their chosen race nutrition.
Taking in more carbohydrate than your gut can absorb will not improve your pace. Excess unabsorbed carbohydrate may remain in the intestine, draw in water, and cause severe gastrointestinal distress. The goal is never to blindly consume maximum calories. The objective is to consume only the precise amount of fuel that your intestinal transporters can actually process.
The duration-based ranges outlined in the segment are rooted in established sports nutrition literature. The presentation attributes its foundational figures to a joint position stand from the Academy of Nutrition and Dietetics, Dietitians of Canada, and the American College of Sports Medicine. It also cites the 2004 study by Jentjens, Achten, and Jeukendrup on high oxidation rates from combined carbohydrates. This foundational research firmly supports the use of multiple carbohydrate sources for long events.
The publication additionally references Jeukendrup’s 2017 paper on training the gut for athletes, which established that gastrointestinal tolerance can be developed through planned practice. The page also cites Podlogar and Wallis’s 2022 review titled New Horizons in Carbohydrate Research and Application for Endurance Athletes. These citations demonstrate a clear movement toward highly individualized nutrition plans. Establishing personalized hourly fueling targets is now a core requirement for serious competitors.
For ambitious athletes over 35, the most practical takeaway is the absolute necessity of gut training. Introducing a new nutrition plan on race day will likely ruin your event. The article describes gut training as repeated exposure to carbohydrate during exercise. The objective is to improve your physical tolerance and help your stomach handle higher intake rates comfortably.
Sports Medicine Weekly proposes a specific four-week progression to build this tolerance safely. In week one, you begin with 30 grams per hour during a single long training session. The target increases to 45 grams per hour in week two. Week three moves the intake to 60 grams per hour. By week four, you rehearse your intended race target at your actual race intensity.
Once you reach the 60 grams per hour threshold, the segment recommends splitting your intake into smaller doses every 15 minutes. This steady trickle is much easier for your digestive system to handle than one massive hourly dose. Athletes should also pay close attention to the fluid concentration of their drinks. The article notes that 6 to 8 percent solutions may empty efficiently, whereas thicker solutions slow gastric emptying and increase bothersome symptoms.
Intensity plays a massive role in how your stomach processes fuel. Tolerance at an easy training pace may not predict your tolerance at threshold or race intensity. Heat, hydration levels, and individual physiology will also heavily affect your gastrointestinal response. You must practice with the specific gels, chews, or solid foods you intend to consume on race day to master this complete guide to sports nutrition.
The broader trend in sports medicine is moving rapidly toward personalized assessment. A related announcement from the University of Birmingham highlights a new testing service called fuelsync®. The university states that its fuelsync® service measures how much carbohydrate an athlete can actually use during exercise. Developed by Professor Gareth Wallis, the platform operates through laboratories at the University of Birmingham’s School of Sport, Exercise and Rehabilitation Sciences.
This commercial service represents a major shift away from generalized advice. Rather than assuming every athlete absorbs carbohydrate at the exact same rate, professionals are attempting to measure individual capacities. You do not necessarily need laboratory testing to succeed, but you do need to understand your own body. Careful self-testing during long training blocks can provide much of the same practical insight. Fine-tuning your carbohydrate periodization requires patience, deliberate practice, and objective observation.
The audience’s age is highly relevant to this testing phase. Adults in the 35 to 65 range may be highly competitive and capable of using the same performance principles as younger athletes. However, age alone does not determine an appropriate carbohydrate rate for your body. Training status, body size, and event duration remain highly relevant to the practical decision.
Pace, heat, and hydration will also dictate your personal tolerance far more than your birth year. Athletes should never interpret the four-week schedule as a rigid requirement. If you develop nausea or bloating, you must adjust the progression immediately. The same rule applies if you experience cramping or diarrhea.
An athlete who performs exceptionally well at 60 grams per hour does not necessarily need to force 90 grams per hour. The most useful target is always the highest intake that supports your long-term endurance performance without causing unacceptable stomach issues.
The bottom line for ambitious veteran athletes is that carbohydrate targets must be scaled to event duration, split between multiple sugar sources for long efforts, and ruthlessly practiced at race pace to ensure gut tolerance.
Follow ReEndure for practical insights on endurance training, recovery, nutrition and healthy aging. Stay connected for new articles, research led guidance and ideas to help you perform better for longer.
Read practical ideas on endurance training, recovery, nutrition and healthy aging to keep progressing for years to come.
Read the Blog