Ironman Nutrition 101: Preventing Muscle Cramps on Race Day

Completing an Ironman isn’t just about fitness - it’s about grit, mental strength, and good old-fashioned preparation. It’s also about how you go about your daily routine during the lead-up to the event. Things like what you eat, how you sleep, and your general stress levels are as important as the race itself.

After all, when you’re pushing yourself to the max across the open water or on the road, every little bit matters.

From your training blocks to your breakfast choices, how you prepare will, at the end of the day, determine your performance on race day. While this might seem common sense, even the most seasoned triathletes have found their races derailed by a familiar and infuriating enemy: muscle cramps.

In this article, we shine the light on how to prevent the dreaded camp from hitting mid-race.

What’s the deal with muscle cramps, anyway?

Often striking without warning, cramps can turn a PB into a DNF. Whether you're lining up for your first Ironman or your tenth, knowing how to keep the cramp away is vital.

Prolonged exertion can disrupt the nervous system’s ability to coordinate muscle contractions, while sweat loss over hours can throw off your body’s salt balance. Interestingly, research shows that cramps often occur late in a race when fatigue is high and electrolyte stores are depleted.

A key cause seems to be linked to fatigue, dehydration, or an imbalance of electrolytes like sodium and magnesium. That’s often where supplements come into play, particularly those that replenish lost electrolytes and minerals.

Heavy training loads, endurance events, and high-pressure races all increase your chances of cramping. But with the right strategies and support, you can minimise how often they strike — and how long they stick around.

Hydration and Electrolyte Strategy

Hydration isn’t just about drinking more water. In fact, overhydration — too much water without enough electrolytes — can be just as risky as dehydration. It can dilute sodium levels in the blood, leading to hyponatremia, which not only increases cramping risk but can also be dangerous.

To strike the right balance, consider your sweat rate, race conditions, and fuelling plan. Sodium is key here, as it helps retain fluid, supports nerve function, and keeps muscles firing. For Ironman athletes, maintaining a steady intake of sodium is a smart move.

At Fixx Nutrition, our CrampFix formula is designed with precisely this in mind — targeted electrolyte support including sodium, magnesium, and key ingredients that interrupt the cramp reflex and get you back on track quickly.

Popular cramp solutions: what works and why

The search for natural ways to stop muscle cramps has brought about a few fan favourites: pickle juice, magnesium supplements, bananas, and sports drinks. But do they actually work?

Pickle juice has surged in popularity thanks to social media and a few small studies showing it can relieve cramps within 30–60 seconds. But it’s not actually about the sodium - it’s the vinegar. Researchers believe the acetic acid triggers a reflex in the mouth and throat that calms overactive motor neurons. However, trying to drink pickle juice from a jar is not without its drawbacks…due to the imprecise nature at times of the ingredients it is very hard sometimes to know what the required dosage may be - meaning that you don’t get the needed relief. This is where CrampFix comes into play. It provides the required ‘neural jolt’ in the precise dosage needed to stop the symptoms and pain  caused by cramping

Magnesium is another key player. It helps muscles relax and supports energy production. That’s why our sports supplements have this all-important ingredient included.

Salt tablets can help replace sodium lost through sweat, but they’re not a complete solution. Taken alone, they don’t address the neural or muscular fatigue components of cramping. They also take time to digest and can cause gut discomfort if not timed well. CrampFix, on the other hand, is a fast-acting, multi-pronged approach.

Preventing cramps through smart fuelling - Fuel X, Fuel X Pro and Fixx Energy Gels

Fuelling isn’t just about calories - it’s about giving your muscles the nutrients they need to perform over hours of work. An imbalance in energy intake can trigger fatigue-induced cramps, especially during the marathon leg. This is something we know a thing or two about.

Two of Fixx Nutrition’s popular products that have paved the way for cramp-free races, Fuel X and Fuel X Pro, are designed to give you a balanced carb blend for fast absorption and sustained energy. Fuel X Pro goes one step further with added amino acids to support muscle endurance and recovery, making it ideal for longer races.

Fixx Energy Gels deliver around 30g of carbs per serve, along with 220mg of sodium. They're easy on the stomach and perfect for topping up glycogen stores during intense efforts. Used together, this fuelling system helps maintain steady blood sugar, supports electrolyte balance, and reduces the risk of late-race cramping.

Race day plan: how to fuel to avoid cramps

Your race-day nutrition plan should be a continuation of your training — not a new experiment. Here’s a framework to work from.

• Pre-race: Begin hydrating in the lead-up to your event using an electrolyte-rich drink like Fuel X. It gives you both fluid and fuel, helping top up carbohydrate and sodium levels before the race begins. Cramp-prone athletes can also take CrampFix before the race as a preventative measure.

• During the race: Use Fuel X or Fuel X Pro during the race to meet your energy and electrolyte needs. These products contain a blend of carbohydrates, electrolytes, and (in the case of Fuel X Pro) amino acids for endurance support.

• Post-race: Rehydrate with a drink that replaces lost sodium and magnesium. A serving of Fuel X post-race can help replenish glycogen and electrolyte stores. Follow with a balanced recovery meal that includes carbs, protein, and salt to support muscle repair and fluid balance.

Listen to your body. Test everything - hydration, electrolytes, fuelling-in your long training sessions. This will help you fine-tune your needs and spot any gaps before race day. Don’t overhydrate.

Getting ready for the big day

Muscle cramps during an Ironman are often caused by fatigue and electrolyte imbalance, so make sure that you prepare properly. Make sure your hydration is taken care of, including both water and sodium.

CrampFix offers a fast-acting, comprehensive solution for athletes that is designed specifically to meet their body’s requirements under the most stressful conditions. 

With Fixx Nutrition’s range of sports supplements, you’ll be crossing that finish line cramp-free in no time. From the first stroke to the final stride, Fixx Nutrition has your back (and your muscles).