Why My Husband Carried Me (Almost) to Gold: The Science Behind HYROX Fitness

There’s nothing quite like agreeing to race alongside your husband to find out exactly where your strengths, and weaknesses, lie.

A few weeks ago we lined up for the Battersea Urban Race by Athena Events. Think of it as HYROX’s slightly shorter cousin: the running is broken into 500m efforts instead of 1km, and the stations are half the volume. We entered the mixed doubles category, which meant we had to complete every run together but could split the work at each station however we liked.

There was just one catch.

In mixed doubles, both athletes use the men’s weights.

As two personal trainers, we were well aware of our limits but told ourselves we’d be absolutely fine.

Reader… it was warm. Very warm. Around 34°C warm! By the second run I was already questioning every life decision that had led me there. And as every perimenopausal woman knows, running in that kind of heat is an extreme sport in itself. For that alone, I deserve a medal!

Strength Isn’t Everything… But It Helps Almost Everything

My husband and I train in remarkably similar ways. Neither of us are bodybuilders, but our training revolves around progressive strength work using a split-body programme, with the goal of getting stronger while building muscle.

The biggest difference being he never runs. I don’t run much either, but I attend one 90-minute HYROX class every week, so I assumed I’d have the edge in terms of cardiovascular fitness.

I was wrong. Spectacularly wrong.

He’s next-level strong. The heavy sleds, carries and strength stations barely registered as exercise for him, while I was working hard from the first station onwards. Yet despite doing very little traditional cardio, he flew through the race.

The reason why lies in something exercise scientists call specificity. His training has developed enormous levels of maximal strength and power. Over repeated 500m efforts, where acceleration, force production and rapid recovery matter, those qualities transferred brilliantly. Add in years of lifting heavy weights and he simply lost very little time at the stations.

Meanwhile, I discovered that burpees may well be my hidden superpower. I’m claiming those as my contribution to our eventual victory.

The Science Explains Why HYROX Is So Brutal

HYROX has become one of the fastest growing fitness sports because it asks your body to do something incredibly difficult.

• Run hard.
• Lift heavy.
• Recover.
• Repeat.

Over and over again.

Unlike a marathon, you never settle into a rhythm. Unlike a gym workout, you never get a proper rest.

Research into the physiological demands of HYROX points to aerobic capacity as an important predictor of performance. VO₂max, the maximum amount of oxygen your body can utilise during exercise, appears to be particularly important.

In simple terms, it’s the size of your engine.

What matters in a hybrid race?

• Aerobic fitness: the engine that keeps you running and helps you recover between stations.
• Strength: the force you need for sleds, carries and other resistance work.
• Muscular endurance: your ability to keep producing force as fatigue builds.
• Recovery: how quickly your body can prepare itself for the next effort.

Many people assume HYROX is won by the strongest athlete. The evidence suggests otherwise. Strength gets you through the stations. Your aerobic fitness determines how quickly you recover before the next run, and whether you can keep producing power as fatigue accumulates.

That’s why someone who can squat twice their body weight can still find themselves shuffling between stations while a lighter, fitter athlete sails past them.

You Need Two Engines

One of the reasons HYROX is so addictive is because it constantly switches between energy systems.

During the running sections your aerobic system is working flat out. Hit the sled push or burpee broad jumps and suddenly your anaerobic system is working overtime.

Hydrogen ions start to build up, the muscles become more acidic and that unmistakable burning sensation kicks in. For years we blamed lactate, but science has largely cleared its name. Rather than being the villain, lactate is now recognised as a valuable fuel that helps shuttle energy around the body while your muscles desperately try to keep you moving.

Research into simulated HYROX competition has recorded blood lactate concentrations of around 8.5 mmol/L during the exercise stations, compared with around 7.7 mmol/L during the running sections.

Yet, despite this, I actually found the running much tougher.

The stations felt like hard strength sessions, something I’d trained for over many years, whereas every 500m run exposed exactly what I’d neglected. It was a reminder that exercise feels hardest where your training adaptations are weakest, not necessarily where your body is under the greatest physiological stress.

By this point, I wasn’t looking forward to the next station but I definitely wasn’t looking forward to another 500m run either. I could feel my body desperately trying to restore oxygen, clear metabolic by-products and replenish energy stores. There was simply no opportunity to recover before it all started again.

Research has also found competitors spending much of a simulated HYROX race at very hard exercise intensity.

That certainly matched my experience.

From running, pushing, pulling, jumping and carrying, it felt like my heart rate had permanently moved into the red zone and had no intention of leaving. There was barely a moment to recover before the next challenge arrived.

All the while, I had one recurring thought: whose ridiculous idea was this?

Mine, of course.

So Was Our Training Good Enough?

Looking back, yes… and no.

Our strength base was undoubtedly an advantage.

Progressive resistance training gave us the force production needed for sleds, carries and functional movements. Years of lifting also built muscular endurance, allowing us to keep producing force despite mounting fatigue.

Research into HYROX performance suggests that aerobic fitness, strength, muscular endurance and the ability to maintain performance under fatigue all matter. That’s one reason why heavy resistance training remains such an important part of HYROX preparation.

Neither of us are regular runners. A fact that became increasingly obvious every time another 500m run appeared on the course.

Without question, more running could have improved our performance. My cardiovascular system would have definitely appreciated a little more preparation.

However, training is always about priorities. We had to balance performance with injury prevention, avoiding unnecessary repetitive impact on joints that have already accumulated plenty of mileage, while staying aligned with our bigger goals of building strength, muscle and maintaining long-term health.

Missing a few minutes on a race clock was a trade-off I was happy to accept.

The Best Athletes Train Both Systems

The research highlights several training methods that can help prepare athletes for the demands of HYROX:

• Progressive strength training to improve force production for sled pushes, pulls and carries.
• High-intensity interval training (HIIT) to develop aerobic and anaerobic fitness.
• Station-specific circuits that replicate race-day fatigue and transitions.
• Local muscular endurance work to improve repeated movements such as lunges, wall balls and burpees.

In other words, don’t just become a stronger lifter or a faster runner.

Become someone who can keep producing force when your muscles are complaining, your lungs are filing a formal complaint and your brain is questioning your life choices.

The Best Part Had Nothing To Do With Winning

Don’t get me wrong, it was lovely discovering we’d won our age category.

Although, in the interests of complete honesty, I suspect the fact that there aren’t quite as many competitors in our age group as the twenty-somethings may have worked slightly in our favour!

I’ll happily take the win regardless.

But my favourite part of the day wasn’t getting our results. It was watching so many of my own clients race. Several finished in the top ten of their age categories, and seeing months of consistent training pay off was infinitely more rewarding than anything I achieved myself.

That’s one of the things I love most about events like HYROX and the Urban Race. The finish line belongs to everyone. Whether you’re chasing a podium, a personal best or simply proving to yourself that you’re capable of more than you thought, crossing that line feels exactly the same.

The Take-Home Message

HYROX rewards athletes who are relentlessly well-rounded. A big aerobic engine matters, but only if it’s supported by enough strength, muscular endurance and resilience to keep moving when fatigue peaks.

So don’t choose between lifting weights and doing cardio.

Do both.

The HYROX training takeaway

• Lift heavy.
• Run regularly.
• Train intervals.
• Practise moving under fatigue.

Because HYROX isn’t about being the strongest person in the room.

Or the fastest runner.

It’s about becoming exceptionally good at doing both, again and again, without slowing down.

And if you’re racing mixed doubles with your spouse?

Choose someone stronger than you.

It worked brilliantly for me.

(Just don’t tell my husband I admitted that.)

Read more about HYROX on EyeOnLondon, and if you’re tempted to try mixed doubles, choose your partner wisely.

For more London arts and culture, visit EyeOnLondon at eye-on-london.com.