Race Day Pacing: How to Avoid Hitting the Wall

You’ve trained for months, nailed your long runs, and shown up ready on race day. Halfway through, your legs turn to concrete, your energy crashes, and every step feels like a battle. Welcome to “the wall”, its sucks. .

Most runners who hit the wall aren’t lacking fitness. The real problem is usually pacing and/or fuelling. The good news is that with the right strategy, you can reduce the risk of a late race blow up and give yourself a much better chance of finishing strong.

In this guide, we’ll cover:

• Why runners hit the wall
• The role pacing plays in race success
• How to pace yourself for different distances
• The connection between fuelling and pacing
• How VO₂ max testing helps you plan your race strategy

Why Do Runners Hit the Wall?

The wall usually shows up in long distance races. It happens when your body burns through stored glycogen and can’t produce energy fast enough to match the effort you’re trying to hold.

The result:

• Fatigue that feels overwhelming
• Heavy legs that just don’t want to move faster
• A sharp drop in pace
• A mental battle just to keep moving

Large analyses of recreational marathoners suggest that runners who hit the wall tend to start too fast and then slow dramatically in the final third of the race. This pattern lines up with the point where glycogen is running low, especially if fuelling has been inadequate.

The Role of Pacing in Race Success

Going out too fast is the most common pacing mistake on race day.

Why it happens:

• Adrenaline is high at the start
• Fresh legs make goal pace feel “too easy”
• Crowds and other runners can pull you along faster than planned

The problem is that if you spend too much energy early on, you’re going to pay for it in the final kilometres.

Smart pacing:

• Keeps your effort and heart rate stable
• Preserves glycogen for the second half
• Reduces the risk of hitting the wall

Research on pacing shows that more controlled strategies, such as even or slight negative splits, are linked with better marathon performance and lower physiological stress than big positive splits.

How to Pace Different Race Distances

These are general guidelines. You’ll still need to adjust for your fitness, conditions, and course. I recommend using the same intensity measurement that you used in your training. That might be a specific pace, heart rate zone, or rate of perceived exertion (RPE).

Breaking the race up into thirds can be helpful in maintaining motivation and focus. This is where your progression runs during your training will really shine! 

5K

• Start controlled, don’t get caught up with the crowd just yet
• Settle into about 90 to 95% effort by the 3k mark
• Use the final kilometre to push the pace

Short races are meant to feel uncomfortable, but the first kilometre still shouldn’t be the fastest.

10K

• The first 3k should feel nice and comfortable
• At the 5-6k mark settle in around your goal pace, focus on quick turnover of your feet and maintaining your posture
• 8-10km is when it starts to really suck, maintain your focus and embrace it. Now the race really begins

Half Marathon

• First 10k should feel good. Relax and enjoy the course. If you’re breathing very hard here, you’ve gone out too fast, dial it back a little
• During kilometres 10-16 think “comfortably hard”, just under lactate threshold
• The final 5k is when it’s time to race. Embrace the suck, keep your upper body relaxed, and push it.

The marathon is all about patience. A common strategy is the 10/10/10 method, breaking the race into the first 10 miles (16k), second 10miles (16-32k) and the final 10k.

• Stick to a comfortable pace slightly lower than your goal marathon pace, even if it feels easier than you expect at the start
• From kilometres 16-32 settle into your goal marathon pace
• Treat the final 10k as the real race!

How Fuelling Ties Into Pacing

Fuelling and pacing are closely linked. Even good fuelling won’t save you if you go out too hard, but smart pacing combined with a solid fuelling plan makes a big difference.

General tips:

• Carb load before race day. Make sure glycogen stores are topped up. This usually starts ~3 days before race day. Only having pasta for dinner the night before a race won’t cut it. 
• Start fuelling early. Take your first gel 15mins before the race start rather than waiting until you feel tired.
• Fuel often. Gels, chews, or sports drink every 30 to 45 minutes works well for many runners.
• Hydrate smart. Avoid both underhydration and overhydration. Sip steadily instead of chugging large volumes all at once.

Current endurance guidelines suggest roughly 30 to 60 grams of carbohydrate per hour for events lasting 1 to 2.5 hours, and up to around 90 grams per hour for longer races if your gut tolerates it and you use mixed carbohydrate sources such as glucose and fructose.

The goal is to keep blood glucose stable and delay the point where glycogen becomes critically low so you can maintain your planned pace.

Working with a Registered Sports Dietician to dial in your fuelling can be a game changer for performance. I recommend No Sweat Nutrition, and if you’re in BC or Ontario this will be covered under most extended health benefits.

If you’d like to dial in your hydration, you can book in for a Sweat Sodium Test with me in Port Moody.

Why VO₂ Max Testing Helps With Pacing

One of the hardest parts of race pacing is knowing what “sustainable” really means for you.

VO₂ max testing helps by:

• Providing accurate training zones based on your physiology rather than generic formulas
• Identifying your thresholds so you know which paces are realistic for different race distances
• Giving you specific heart rate and pace ranges you can use in both training and racing

Recent work has highlighted VO₂ max testing as one of the most precise ways to individualise training zones and race pace, especially when it’s combined with threshold data. If you want to learn how to use those zones in everyday training, read my post on heart rate training for runners.

Instead of running on guesswork, you’re racing with a personalised roadmap you’ve already rehearsed in training.

[Related: What Is VO₂ Max Testing? Everything Runners Need to Know]

Actionable Tips to Avoid Hitting the Wall

1. Practice race pace in long runs. Include sections at goal pace during longer sessions so it feels familiar.
2. Dial in your fuelling plan during training. Practice what, when, and how much to take, don’t try anything new on race day.
3. Start slightly slower than you think. Let the race come to you in the second half.
4. Use heart rate or RPE if pace is hard to judge. This is especially useful on big city courses where the GPS in your watch can be impacted by tall buildings
5. Stay patient. Race day rewards patience and discipline

Key Takeaways

• Hitting the wall is usually linked to pacing and fuelling, rather than a simple lack of fitness
• Each race distance has its own pacing profile; shorter races tolerate higher relative effort, marathons demand more restraint
• Fuelling supports your pacing strategy but can’t fully rescue an overly aggressive start
• VO₂ max testing helps you understand your training zones and likely race pace, so you can line up with a clear plan

Ready to Run Your Best Race?

If you want to avoid the wall and finish strong, book a VO₂ max test in Port Moody to get personalised pacing zones for a smarter training plan.

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