How much should you drink, when do you need electrolytes, and how can you build your own hydration strategy? We talk a lot about carbohydrate fuelling when it comes to endurance performance. But there's another part of the equation that can have a huge impact on how you train and race: Hydration. And hydration isn't simply about drinking more water. Your fluid requirements are individual and can change dramatically depending on how long you're exercising, how hard you're working, the temperature, humidity, sun exposure, your clothing, your sweat rate and how much sodium and other minerals you lose in your sweat. Get it right and you're giving your body the best chance of performing as intended. Get it wrong and you may find yourself struggling with heat, fatigue, reduced exercise capacity or gastrointestinal discomfort. So let's look at what actually matters. WHY DOES HYDRATION MATTER FOR PERFORMANCE? During exercise, your working muscles produce heat. Sweating is one of your body's primary ways of getting rid of that heat. As you sweat, you lose fluid and minerals. If those losses become substantial and aren't appropriately managed, cardiovascular and thermal strain can increase and exercise performance can be affected, particularly during prolonged exercise and in hot conditions. But there's an important distinction: Hydration isn't about replacing every drop of sweat. It's about developing a strategy that appropriately manages your individual fluid losses without over-drinking. And that strategy will look different for different athletes. NOT EVERY TRAINING SESSION NEEDS THE SAME AMOUNT OF FLUID Think about the difference between: A 45-minute easy run on a cool morning and a three-hour long run in 30°C heat and high humidity. They're both running. But your hydration requirements could be dramatically different. The same applies to cycling, triathlon, HYROX and other endurance sports. Your hydration strategy should reflect the demands of the session and the environment you're exercising in. WHAT MAKES YOU NEED MORE FLUID? Several factors can increase your fluid losses. 🌡️ TEMPERATURE As the temperature rises, your body needs to work harder to dissipate heat. That generally means increased sweating. A session that feels perfectly manageable in cool conditions can become considerably more demanding when performed in hot weather. 💧 HUMIDITY Humidity can make cooling more difficult because sweat doesn't evaporate as effectively when the surrounding air is already humid. You may therefore sweat heavily without getting the same cooling benefit. Hot and humid conditions can be particularly challenging for endurance athletes. ☀️ SUN EXPOSURE Training in direct sunlight can increase your heat load compared with exercising in shade. Two sessions performed at the same air temperature can therefore feel very different depending on whether you're running in direct sun, under cloud cover or indoors. 🏃 EXERCISE INTENSITY The harder you work, the more heat your body produces. A relaxed aerobic run and a hard interval session can therefore produce very different sweat rates, even when performed in the same environment. HYROX is a great example. You're combining running with repeated high-intensity functional movements, creating a significant cardiovascular and thermal demand. ⏱️ DURATION The longer you exercise, the more opportunity there is to accumulate fluid losses. A 45-minute session and a four-hour endurance event require very different planning. For shorter sessions in comfortable environmental conditions, many athletes can rely largely on normal daily hydration and drink according to thirst. As exercise duration increases, particularly during prolonged endurance exercise, paying closer attention to fluid and electrolyte losses becomes increasingly important. YOUR SWEAT RATE IS UNIQUE TO YOU This is one of the most important things to understand. We don't all sweat the same amount. Two athletes can run side by side for two hours in exactly the same conditions and lose very different amounts of fluid. Some athletes are heavy sweaters. Others sweat considerably less. Some athletes lose more sodium in their sweat. Others lose less. This is why copying another athlete's hydration strategy isn't necessarily going to work for you. Your hydration strategy should be yours. HOW CAN YOU WORK OUT YOUR SWEAT RATE? You can do a simple field test during training. BEFORE YOUR SESSION Weigh yourself with minimal clothing. Record your weight. DURING YOUR SESSION Record: · How much fluid you drink · How long you exercise · The environmental conditions · Any urine produced during the session AFTER YOUR SESSION Weigh yourself again, ideally after drying off and changing out of wet clothing. A simplified calculation is: Sweat loss = pre-exercise weight − post-exercise weight + fluid consumed − urine produced For example: You start at 70.0 kg. You finish at 69.0 kg. You drink 1.0 litre during the session. You don't urinate. Your estimated sweat loss is approximately: 2.0 litres If the session lasted two hours: Estimated sweat rate = approximately 1.0 litre/hour. Repeat this test under different conditions and you'll start to build a much clearer picture of your individual requirements. YOUR SWEAT RATE CAN CHANGE Your sweat rate isn't fixed. You might lose: 0.5 L/hour during a cool morning run. But perhaps: 1.0 L/hour during a warm afternoon. And potentially considerably more during a long session in hot, humid conditions. Same athlete. Different environment. Different hydration strategy. WHAT ABOUT ELECTROLYTES? This is where things get a little more interesting. Sweat doesn't contain only water. You also lose electrolytes — including sodium, chloride, potassium, calcium and magnesium. The amount you lose varies considerably between individuals. Some athletes are naturally higher-salt sweaters. Others lose considerably less. This is one reason electrolyte requirements can't simply be reduced to: "Everyone needs electrolytes." For many athletes exercising for less than 60–90 minutes in normal conditions, a normal diet will generally provide sufficient electrolytes. However, electrolyte replacement can become increasingly relevant when you have: · High sweat rates · Long-duration exercise · Significant sweating · Hot or humid conditions · Multiple training sessions · Evidence of high sweat sodium losses · Limited opportunities to replace electrolytes through food during exercise The AIS recognises electrolyte supplementation as particularly useful in situations involving substantial sweat losses and prolonged exercise. (ausport.gov.au) ELECTROLYTES DON'T JUST MEAN SODIUM Sodium is the major electrolyte lost in sweat and therefore receives much of the attention in endurance nutrition. But electrolytes are a broader group of minerals. Our BYF Electrolyte Mix contains a blend of mineral salts providing: Magnesium Potassium Calcium It has been designed to give athletes another flexible option when building their hydration strategy. And this is where we think it becomes particularly useful. TWO WAYS TO USE BYF ELECTROLYTES 1. MAKE YOUR OWN ELECTROLYTE DRINK Simply mix the BYF Electrolyte Mix with water to create your own electrolyte drink. This gives you a straightforward way to include electrolytes during training, racing or throughout the day when appropriate. Your carbohydrate and hydration strategies don't always need to be combined. Sometimes you simply want: Water + electrolytes. 2. ADD IT TO YOUR BYF CARBOHYDRATE MIX This is where the BYF system really comes together. You can add your BYF Electrolyte Mix to your carbohydrate mix to create your own carbohydrate + electrolyte fuel. That means one soft flask can contain both the carbohydrate you're using for fuelling and the electrolytes you're choosing to include as part of your hydration strategy. Build your fuel. Build your hydration. You control what goes into your flask and can adjust your strategy around the demands of your training or race. WHY WE LIKE THE BYF SYSTEM This is exactly how we use it ourselves. We're endurance athletes training and racing across HYROX, running and triathlon, and our hydration needs aren't the same every day. A short training session in cool conditions might require very little during the session. A long run in the Australian summer is completely different. An Ironman 70.3 is different again. Instead of having one product that tries to do everything, we wanted a system that gives athletes flexibility. BYF Carbohydrate Mix Build your carbohydrate fuel. BYF Electrolyte Mix Build your electrolyte drink. BYF Carbohydrate + Electrolyte Combine the two when your training or race demands it. One system. Your strategy. HOW MUCH SHOULD YOU DRINK? There isn't one magic number. Your goal isn't necessarily to replace 100% of the fluid you lose during exercise. In fact, drinking substantially more fluid than you're losing can be dangerous. Exercise-associated hyponatremia can occur when excessive fluid intake dilutes the sodium concentration in your blood. Severe cases can be life-threatening. (ausport.gov.au) Instead, develop a strategy based on: Your sweat rate. Your exercise duration. Your intensity. The environment. Your access to fluid. Your individual tolerance. And, when appropriate, your electrolyte requirements. DON'T WAIT UNTIL RACE DAY Just like carbohydrate fuelling, hydration is something you can practise. Your long training sessions are the perfect opportunity to experiment. Try different fluid volumes. Measure your sweat rate. Pay attention to the conditions. Work out what feels comfortable. Practise carrying your bottles or soft flasks. Test your carbohydrate and electrolyte combination. Then refine it. Your race-day strategy should not be a first experiment. HYDRATION FOR MARATHON, TRIATHLON, HYROX & ULTRA Different events create different hydration challenges. MARATHON Long duration, potentially high temperatures and limited opportunities to drink can make hydration planning important. IRONMAN & 70.3 Several hours of continuous exercise combined with changing environmental conditions means hydration and electrolyte planning become an important part of race preparation. HYROX High-intensity running combined with functional stations creates significant cardiovascular and thermal demands, particularly during longer sessions and warmer conditions. ULTRA RUNNING Long duration means prolonged exposure to fluid losses, often combined with changing terrain, temperature and access to aid stations. There is no universal strategy. The event determines the demands. Your body and your environment help determine the solution. THE BIGGEST HYDRATION MISTAKES? ONLY THINKING ABOUT WATER. Hydration is more than just drinking water. COPYING SOMEONE ELSE'S PLAN. Your sweat rate isn't necessarily the same as theirs. IGNORING THE ENVIRONMENT. A strategy that works at 10°C may be completely inadequate at 30°C. WAITING UNTIL RACE DAY. Your hydration strategy should be pract More fluid isn't automatically better. --- BUILD YOUR HYDRATION STRATEGY Before a long training session or race, ask yourself: How long am I going to be exercising? How hard am I going to be working? What's the temperature? What's the humidity? Will I be in direct sun? How much do I normally sweat? How much fluid can I realistically carry? Will I need electrolytes? Am I also taking carbohydrate? Then build your strategy. HYDRATION IS PART OF PERFORMANCE When you're preparing for a marathon, Ironman, HYROX or ultra, hydration shouldn't be something you think about only when you're already thirsty. It should be part of your preparation. Your training plan tells you how far you're going. Your fuelling plan tells you where your carbohydrate is coming from. Your hydration plan tells you how you're going to manage the fluid and electrolyte losses along the way. And when the environment changes, your strategy needs to change too. Cool morning? Your needs may be lower. Hot afternoon? Your fluid losses may increase. Hot + humid + long duration + high sweat rate? Now hydration and electrolyte planning become a much bigger part of your performance strategy. BUILD YOUR HYDRATION. BUILD YOUR FUEL. This is why we created BYF as more than just a carbohydrate mix. We wanted athletes to have the flexibility to build their own fuelling and hydration strategy. Use the carbohydrate mix when you need carbohydrate. Use the electrolyte mix when you need electrolytes. Or combine them to create your own carbohydrate + electrolyte fuel in a reusable soft flask. Mix it. Fill it. Carry it. Fuel it. Your training is individual. Your sweat is individual. Your environment is constantly changing. So why shouldn't your hydration strategy be individual too? BUILD YOUR FUEL. BUILD YOUR HYDRATION. TRAIN SMARTER. GO FURTHER.

From 30 g to 120 g per hour — what does the latest research actually tell us? If you've spent any time around endurance sport, you've probably heard the familiar advice: "Have a gel every 30 minutes." For years, that was a pretty common approach to endurance fuelling. But sports nutrition is evolving. We're now seeing elite endurance athletes routinely consuming 90, 100 and even 120 grams of carbohydrate per hour during prolonged training and racing. So has the old 60–90 g/hour advice changed? Yes — but there's more to the story. The latest research is challenging the idea that 90 g/hour is the absolute ceiling for carbohydrate intake during endurance exercise. At the same time, 120 g/hour is not a recommendation that every athlete should immediately adopt. The real evolution is understanding that carbohydrate intake can be trained, individualised and progressively increased. FIRST, WHAT DOES THE AIS RECOMMEND? The Australian Institute of Sport (AIS) remains one of our most useful evidence-based resources for sports nutrition. Its current guidance gives the following carbohydrate targets during exercise: Exercise duration Current AIS guidance Under 45 minutes Generally not required 45–75 minutes, high intensity Small amounts may be useful 1–2.5 hours 30–60 g carbohydrate/hour Exercise duration Current AIS guidance 2.5–3+ hours Up to 90 g carbohydrate/hour For prolonged endurance exercise, the AIS also recommends practising your fuelling strategy in training and choosing an approach that suits your individual goals, hydration needs and gut comfort. So where does the new 120 g/hour conversation come from? 90 G/HOUR ISN'T NECESSARILY THE END OF THE STORY For a long time, the practical thinking around carbohydrate intake was that approximately 60 g/hour was the upper limit for glucose-based carbohydrate. This is because glucose is absorbed through a transporter in the small intestine called SGLT1. Once this pathway becomes saturated, simply adding more glucose doesn't necessarily mean more carbohydrate will be absorbed and used. It can also increase the likelihood of gastrointestinal problems. But researchers discovered something important: Different carbohydrates can use different transport pathways. Fructose, for example, is transported through a different pathway. This led to the development and use of multiple-transportable carbohydrate strategies — typically combinations of glucose-based carbohydrate and fructose — allowing athletes to potentially absorb and oxidise carbohydrate at higher rates. The AIS now specifically recognises multiple-transportable carbohydrate products as useful when athletes are targeting higher carbohydrate intakes during prolonged exercise. And this is where the research gets really interesting. THE MOVE TOWARDS 120 G/HOUR A recent study published in the Journal of Applied Physiology investigated carbohydrate intake of 60, 90 and 120 g/hour in eight elite male marathon runners. These weren't recreational runners. The athletes had an average marathon personal best of approximately 2 hours 23 minutes. The researchers found that carbohydrate oxidation increased as intake increased, with the 120 g/hour condition producing greater exogenous carbohydrate oxidation than both 60 and 90 g/hour. They also observed a lower oxygen cost of running at 120 g/hour. However — and this is important — gastrointestinal symptoms were also a consideration at the higher intake. So the takeaway isn't: "Everyone should now consume 120 g/hour." It's: "The human capacity to use carbohydrate during prolonged exercise may be higher than previously thought — particularly in well-trained athletes using multiple-transportable carbohydrates and a trained gut." That is a very different message. WHAT ABOUT 120–200 G/HOUR? This is where we need to separate what athletes are experimenting with from what the research has firmly established. Elite endurance sport is increasingly seeing athletes consuming carbohydrate at rates above 90 g/hour, with some strategies reaching 120 g/hour and beyond. But the evidence does not currently justify telling every endurance athlete that they should consume 120–200 g/hour. Higher is not automatically better. The emerging research is asking a much more interesting question: What is the highest carbohydrate intake an individual athlete can effectively absorb, tolerate and use during their particular event? And that answer will be different for different athletes. YOUR BODY WEIGHT DOESN'T GIVE YOU THE WHOLE ANSWER This is an important point. It is tempting to create a simple formula: Body weight × X grams = your hourly carbohydrate target. But that's not how the current AIS recommendations are structured. The AIS carbohydrate targets are primarily based on exercise duration and intensity, rather than simply body weight. A 55 kg runner and an 80 kg runner completing the same marathon don't automatically need completely different hourly carbohydrate targets. However, body size can still provide useful context when developing an individual fuelling strategy. So rather than giving you one "correct" number based on your weight, think in terms of ranges and progression. A PRACTICAL CARBOHYDRATE SCALE This isn't an AIS prescription. It's a practical framework for understanding how carbohydrate intake might progress as an athlete becomes more experienced with fuelling. Training / racing level Carbohydrate target: Starting out 30–45 g/hour Regular endurance training 45–60 g/hour Well-practised endurance athlete 60–90 g/hour Highly trained athlete 90–120 g/hour* Above 120 g/hour Emerging research — individual/experimental *120 g/hour should be viewed as an advanced strategy, not a universal recommendation. It is most relevant to prolonged, demanding endurance exercise and should be introduced progressively. The AIS currently supports 30–60 g/hour for 1–2.5 hours and up to 90 g/hour for ultra-endurance exercise lasting more than approximately 2.5–3 hours. The newer research suggests that some highly trained athletes may be able to use more. But getting there is a process. YOU CAN TRAIN YOUR GUT This might be one of the most important concepts in modern endurance fuelling. Your legs aren't the only thing you train. You train your gut too. If you're used to consuming 30 g of carbohydrate per hour and suddenly attempt 120 g/hour on race day, there's a very good chance your stomach is going to let you know about it. Instead, carbohydrate intake can be progressively increased during training. For example: Week 1–2: 40 g/hour ↓ Week 3–4: 50–60 g/hour ↓ Week 5–6: 70–80 g/hour ↓ Later training: 90 g/hour ↓ Advanced strategy: potentially 100–120 g/hour The exact progression will depend on the athlete, the sport and the duration of training. The important principle is: Don't race with a fuelling strategy you haven't trained. The AIS specifically recommends practising your fuelling plan during training and notes that the gut can be trained to improve carbohydrate tolerance. WHY TAKE SMALL AMOUNTS MORE OFTEN? Let's say your target is: 90 g carbohydrate/hour You could consume: 45 g every 30 minutes But you could also spread it out: 30 g every 20 minutes or: 22–23 g every 15 minutes Your total hourly intake is approximately the same. For some athletes, smaller and more frequent amounts can simply be a more practical way to manage their fuelling. And this is one of the reasons we love using a soft flask. BYF SOFT FLASKS Instead of carrying six individual gels and trying to remember when to open each one, you can carry your prepared carbohydrate fuel in one reusable flask and take smaller amounts throughout your session. WHAT DOES 120 G/HOUR ACTUALLY LOOK LIKE? This is where the numbers start to sound pretty intimidating. 60 g/hour 15 g every 15 minutes 20 g every 20 minutes 30 g every 30 minutes 90 g/hour 22.5 g every 15 minutes 30 g every 20 minutes 45 g every 30 minutes 120 g/hour 30 g every 15 minutes 40 g every 20 minutes 60 g every 30 minutes Suddenly, you can see why how you carry your fuel matters. Trying to consume 120 g/hour exclusively through individual sachets can mean a lot of packaging, a lot of opening and a lot of decision-making. A soft flask allows you to prepare your total fuel in advance and take smaller amounts as you go. DOES EVERY ATHLETE NEED 120 G/HOUR? Absolutely not. This is probably the most important message in this entire article. If you're running for 60 minutes, you don't suddenly need 120 g of carbohydrate per hour because elite marathoners are doing it. If you're doing a 90-minute training session, 30–60 g/hour may be perfectly appropriate depending on the intensity and your individual goals. If you're racing a marathon, Ironman, 70.3 or ultra, your carbohydrate requirements may be considerably higher. And if you're a highly trained endurance athlete preparing for a long, demanding event, progressively training towards 90–120 g/hour may be a strategy worth considering. The goal isn't to consume the biggest number. The goal is to find the highest intake that works for you. WHAT ABOUT HYROX? HYROX is an interesting one because it sits somewhere between endurance and high-intensity functional fitness. A HYROX race isn't a traditional endurance event, but it can still take well over an hour for many athletes and involves sustained running combined with repeated high-intensity functional stations. Carbohydrate availability matters during this type of training and racing too. For a shorter HYROX session, you may not require the same carbohydrate strategy as someone completing a four-hour Ironman bike leg. But for longer HYROX training sessions, race simulations or athletes completing multiple sessions across a training week, carbohydrate fuelling can become an important part of the overall strategy. Again: The demands of the session determine the strategy.