Fuelling Hybrid Performance: What Runners Can Learn from Saskia Millard’s Journey into HYROX

There’s a noticeable shift happening in endurance sports right now.

The long-standing narrative of “lighter is faster” is being challenged by a new generation of athletes who are not only fast, but strong, robust, and resilient. Saskia Millard is a perfect example of this.  

From an elite running background marked by early success, setbacks, and significant injury, to becoming one of the fastest European HYROX athletes ever, her story is not just about performance. It’s about learning—often the hard way—how to fuel properly. 

And from a dietitian’s perspective, her journey reinforces one of the most important truths in sport nutrition: Fuel is not just supportive, it is performance-defining. 

From Underfuelled to Unlocked Performance

Saskia’s early career reflects a pattern that is still incredibly common in female endurance sport. Despite competing at a high level, she experienced multiple stress fractures, including two femoral neck fractures. These are not random injuries; clinically, they are strongly associated with low energy availability. 

At the time, her instinct was to look at training. She believed she needed to train smarter, push harder, or adjust her programme. What is often missed in these situations is that the issue isn’t always the training load itself, but whether the body is adequately supported to handle it. 

From a clinical standpoint, this is where Relative Energy Deficiency in Sport (RED-S) comes into play.

When an athlete is not consuming enough energy to support both training demands and basic health needs, the body begins to downregulate processes that are not essential for immediate survival. Over time, this can affect bone health, hormonal function, metabolism, and ultimately performance. 

What stands out in Saskia’s reflection is how subtle this can feel – it doesn’t always present as something obvious. Instead, it can feel like your body is not coping, when in reality it is under-fuelled. 

The Shift: From “Light” to “Strong”

A turning point in Saskia’s career came when her approach to training and nutrition changed.

Under her dad’s guidance—whose background is in pro rugby, not endurance running—the focus shifted away from high mileage and toward strength, robustness, and long-term sustainability.

Her weekly running volume is relatively low for an elite athlete, often sitting between 12 and 20 miles. However, this is balanced with a strong emphasis on strength and conditioning, alongside a focus on fuelling.

This aligns more closely with what dietitians now understand about long-term performance, particularly for female athletes.

Strength training supports injury prevention and durability, but it only works if the body has enough energy available to adapt. Without sufficient fuel, you cannot build muscle, improve resilience, or recover properly.

This is where many athletes still get it wrong. They try to add strength work or increase intensity without increasing their energy intake.

HYROX: A New Kind of Demand

Transitioning into HYROX introduces a different set of nutritional demands. Unlike middle-distance running, where races require in-race fuelling, HYROX involves sustained high-intensity work for nearly an hour, combining running with repeated strength-based stations.

This means there is a greater reliance on carbohydrate availability. High-intensity = heavy dependency on glycogen stores and circulation to maintain output. Without adequate carbohydrate intake, fatigue can set in quickly, particularly in the later stages.

Saskia describes this shift as a learning curve, but also something she’s fully embraced. Rather than nutrition being something that sits in the background, she now recognises it as a key driver of performance.

The Race That Changed Everything

One of the clearest demonstrations of how powerful fuelling can be comes from Saskia’s back-to-back races in Glasgow and London. 

In Glasgow, she went out hard and felt strong initially, but by the time she reached the final stations, she completely ran out of energy. The wall balls became a major struggle, taking significantly longer than expected and feeling almost impossible to complete.

One week later, in London, her approach was different. She increased her carb intake in the days leading up to the race. She implemented a clear fuelling strategy on the day itself, including the exclusive SiS Lab Gel 30 minutes before starting, a SiS GO Energy + Electrolytes Gel 5 minutes before starting, another after station 3, and a GO Isotonic Energy Gel at station 6. This was supplemented with sipping on a GO Energy Isotonic Sports Drink at regular intervals.

The result was a dramatic change. She felt stronger throughout and was able to maintain output levels later in the race, taking over three minutes off the Wall Ball Station alone, without any additional training in between.

This is a clear example of the difference between starting a race under-fuelled versus properly fuelled.

What This Looks Like In Practice

For athletes looking to apply this, the key is to think about fuelling as a structured part of performance rather than an afterthought.

In the days leading up to an event, increasing carbohydrate intake becomes essential. This doesn’t need to be overly complicated, but it does require a conscious effort to prioritise carbohydrate-rich foods and increased portion sizes. Glycogen stores are one of the primary limiting factors in performance, particularly in events lasting around an hour at high intensity.

On race day, having a pre-race meal 2-4 hours beforehand helps ensure energy availability. A smaller top-up closer to the start can help maintain blood glucose levels. During the race itself, taking in regular carbs can make a significant difference, particularly in preventing the energy drop that many athletes experience in the later stages. 

This is where practical options, such as GO Isotonic or BETA Fuel gels as easy-to-digest carbohydrate sources, are useful. They provide a convenient way to maintain energy levels without causing gastrointestinal discomfort, especially when intensity is high. 

Training Nutrition: The Power of Consistency

One of the most valuable shifts in Saskia’s approach was moving away from short-term thinking and toward consistency. Earlier in her career, she would adjust her intake based on the session, eating more on harder days and less on easier ones. What she has since learned is that this approach can be limiting. 

Adaptation does not occur during the session itself; it happens afterwards, during recovery. That process is highly energy dependent. If an athlete under-fuels on rest or lighter days, they are effectively limiting the benefit of the work they have already done. 

Now, her focus is on ensuring she eats enough every single day, considering not just training but also the demands of her job as a doctor, general movement, and overall life stress. When you consider all these factors together, total energy needs are often far higher than athletes expect. 

Recovery. Where Performance is Built

Recovery nutrition is one area where Saskia is particularly disciplined. She prioritises refuelling within 20 minutes of finishing a session, typically using a combination of protein, carbohydrates, and something quick and practical.

This immediate intake helps glycogen replenishment and muscle repair, setting up the body for the next session. Waiting too long to eat can delay recovery and increase fatigue, particularly when sessions are frequent or demanding. 

What’s important here is not perfection, but consistency. Even on long days or late finishes, she makes a point of refuelling properly. For individuals on tight schedules, all-in-one recovery shakes, such as SiS REGO Recovery, provide the carbohydrates & protein needed to start recovery without extensive preparation or a large appetite.

Fuelling in a Busy, Real-World Schedule

One of the most relatable aspects of Saskia’s approach is how she manages nutrition alongside a demanding full-time job. With unpredictable shifts and limited breaks, she relies heavily on preparation and convenience.

She focuses on making sure she always has access to food. Carrying snacks, choosing quick options, and being willing to eat whenever possible allow her to maintain energy levels throughout the day.

This is the approach most athletes need. Real life rarely allows for ideal conditions, so building a flexible, practical system is far more effective.

Strength, Protein, and Long-Term Health

With a strong emphasis on strength training, protein intake has become a key part of Saskia’s nutrition strategy. She aims for a relatively high intake, distributed consistently across the day rather than concentrated in one meal. 

This supports muscle repair, adaptation, and overall resilience—particularly important given her injury history. However, it is important to recognise that protein alone is not enough. Without adequate total energy intake, the body cannot effectively use protein for its intended purpose. 

Hydration: Small Changes, Big Impact

Hydration is another area where Saskia has seen noticeable improvements, particularly with the introduction of electrolytes. As someone who sweats heavily, simply drinking water is not always sufficient.

By being more proactive with fluid and electrolyte intake, she has noticed improvements in energy levels and overall performance.

This is a reminder that hydration is not just about avoiding dehydration, but about optimising how the body functions under stress. 

Changing the Narrative Around Body Composition

One of the most important aspects of Saskia’s story is her perspective on body composition in sport.

Endurance running has long been associated with a lean physique, often to the point where it becomes a defining characteristic of performance. However, this can be misleading and, in many cases, harmful. 

Saskia has experienced the consequences of being too lean, including repeated injuries and disrupted training. Since shifting her focus toward strength, fuelling, and overall health, she has seen improvements not only in performance but also in her relationship with sport. 

Final Thoughts

Saskia Millard’s journey highlights something that cannot be overstated: you cannot separate performance from fuelling. 

Her progression has not come from dramatically increasing training volume or radically changing her programme. Instead, it has come from: 

• Fueling adequately 
• Recovering consistently
• Shifting her mindset toward long-term health

For athletes, the takeaway is clear. If you want to train hard, perform well, and stay healthy, nutrition cannot be an afterthought. It has to be a priority. 

Because ultimately, the difference between feeling strong at the end of a race and falling apart often comes down to one simple question: 

Did you fuel for the performance you were asking your body to deliver?