Home » What Is “Bonking” in Cycling? Causes and Prevention

What Is “Bonking” in Cycling? Causes and Prevention


Bonking,’ or hitting the wall, is a rite of passage for all cyclists. Bonking is known to cause cyclists to lose balance suddenly, and potentially lead to more serious injuries. But, what causes bonking and can it be prevented? 

Bonking occurs when the glycogen in the muscles and liver is depleted. Cyclists try to avoid bonking by eating lots of carbohydrates before the race, with more conscientious consumption around 2-3 days before the competition.

Although bonking isn’t completely unavoidable, especially for beginner cyclists, it is possible to manage. This article will discuss the causes of bonking as well as preventative methods, so continue reading! 

Your Body Is Low on Glycogen

The worst nightmare of an athlete is hitting the wall, especially mid-race. “Bonking” refers to extreme fatigue triggered by hitting the wall or the ‘bonk.’ The feeling is overwhelming. It comes with symptoms such as loss of coordination, dizziness, muscle cramping, and virtual hallucination.

When your body runs out of glycogen, you may feel light-headed—even though the muscles and liver retain the glycogen that cyclists expend throughout a race. Once they reach their maximum, movement may feel tough due to a loss of strength, and you may have peripheral vision loss.

How To Prevent Low Glycogen

To prevent bonking, you should consume carbohydrates for the preceding event. Glycogen enhances a cyclist to race without tiring out. Note that the body can accommodate a certain number of carbs—for an average person that’ll be about 300 g (0.66 lb) which equates to 1,200 calories of energy. 

Furthermore, these carbs are processed into energy; once you start biking, the faster you ride, the more power you consume. You can then use up to about 800 calories within an hour. You’ll need to replenish with carbohydrate-rich foods and beverages.

Bonking can be a frightening experience, but it can be avoided if you expect and plan for it. Sustaining a regular carbohydrate intake during your ride is a great way to do this.

You Haven’t Consumed the Right Amount of Carbohydrates

A cyclist should take a decent amount of carbohydrates if training. Not having the right amount of carbs, electrolytes, and H20 is crucial if you’re to ride in a competition. Having too many carbs or not enough can eventually cause bonking.

Since individual tolerance levels are different, it’s important to understand the capacity of calories and carbs your body can take in. Feed your body with enough carbs days before the commencement of the race. 

Eating fatty or greasy foods aren’t beneficial to satisfy your carbohydrate intake. Pasta and rice are more ideal foods that’ll help you store glycogen.

Carb Loading

Every day, consume a carbohydrate-rich diet. While opinions differ on what constitutes “enough,” strive for a 40-65 percent carbohydrate diet. The best value is, once again, based on the individual and genetics.

Carb load on healthy, high carb foods

Carb loading is a perfect way to protect yourself from bonking. It ensures you’ve stored enough glycogen before going out on a ride. Although a slow process, it’ll help you keep enough carbohydrates for the race. It takes about two days to get the right amount of carbs stored for an upcoming race.

There are several practical sources of carbohydrates, including sweet potatoes, pasta, rice, dried fruits, fresh fruits, and oats.

A good amount of carbohydrates, combined with hydration, energy drinks, and an energy bar, prevents becoming excessively weak while riding. 

Consume Carbohydrates on the Bike

This is rudimentary, especially for novice cyclists, but vital to remember: if your ride is above 90 minutes, you should consume some carbohydrates while on the move. Genetics determine how long a rider can sustain energy before refueling. It’s cogent to know how long your muscles can maintain the glycogen before you refuel.

Most people maintain an energy supply for about 90-120 minutes; if that elapses, a cyclist has to replenish, while the supply of sugar to muscles helps a rider keep balance. It usually takes 1-2 hours before complete exhaustion kicks in, but most cyclists have a limit of 90 minutes to refuel.

If a cyclist doesn’t replenish after a long ride, they will soon feel hollow, tired, and worn.

Always Have Good Feeding Plan for Cycling

A typical blunder is assuming that you don’t need to start replenishing glycogen until you’re well into a ride. Maastricht University researchers disproved this theory by observing ten male individuals over a three-hour cycle ride. 

Sports drinks were observed to minimize the glycogen necessary to maintain a given speed throughout the activity, not just at the end when the bonk threatened to hinder the athlete. As a result, it’s critical to start sipping as soon as possible, so you can better maintain your glycogen levels throughout the ride. Don’t wait till the deed is almost done to act.

Making a strategic plan before your ride is crucial. When setting out for cycling, decide what you will drink or eat. A proper analysis of how long your energy supply will take will ease this process. Benchmark the number of energy bars, water, and even sandwiches your body needs for a ride.

If you’re riding with a buddy or teammate, keep an eye out for each other and set a reminder to refuel if you’re a forgetful person. Whatever technique you choose, make sure to plan ahead of time because it’s too late to make good fueling decisions once you’re on the bike.

Eating can be challenging once you start bonking because you’ll be experiencing nausea. The remedy is to refuel; little fluids with your food will help you obtain the refreshing taste of carbs in your body, and your brain will typically respond positively.

Finally, knowing how many carbohydrates to ingest throughout a ride is critical if you want to avoid bonking.

You Aren’t Pacing Correctly

Imagine biking along, enjoying yourself, when you’re suddenly dumped from the rear of the pack. You strive to get back on your feet, but you’re out of options. You can’t go another stroke on the pedals, but even the slowest speeds are excruciating

Your legs become like concrete, concentration becomes a challenge, and full-body tiredness sets in. This is bonking. It’s disastrous for a cyclist, and however, with a concise plan, you can manage or avoid the situation with this essential skill, ‘pacing.’

Pacing is crucial in managing you energy levels.

Pacing is crucial in avoiding the bonk because the practice helps you manage your energy levels. The harder you cycle, the faster your glycogen stores are expended. It’s beneficial to have a long-ride strategy and to be mindful of your exertion levels. 

Proper pacing is a necessary skill that can set you up for success if you apply it along with refueling and topping up your reserve before a ride. Keep this to heart while cycling and don’t go too hard on yourself.

Pacing also affects your performance in a race. Simply a few percentage points lower performance can keep you from attaining your full potential. 

Setting a new personal best might come down to the tiniest of margins, especially if you’re a seasoned cyclist getting the most out of your training. While riding, don’t go harder than usual. You can use a Garmin, a great tool to track your pace, but don’t become dependent on this training tool.

According to studies, the best pacing technique for a 5k race is to run the first mile 3 percent faster than the goal pace. Running the first mile more than 6% faster than the desired race pace, on the other hand, significantly lowers performance; in fact, nearly all of the individuals who ran faster than 6% didn’t even finish the race.

These results can also be applied to cycling, and starting too quickly can be disastrous if your objective is to create a new personal best.

If you’ve ever prepared for a marathon, you’ve heard the phrase “putting time in the bank,” which refers to running the first half of the race slightly faster than the goal pace to make up for a slow last 10 kilometers (6.21 mi). Sadly, from a physiological and scientific basis, this racing technique is entirely incorrect.

The utilization of carbs or fats as a primary fuel source is the biggest flaw with the “time in the bank” technique. Since carbohydrates are the source of energy, your performance will decrease if you burn up your available carbohydrate resources, especially if you “bonk.”

Practice Pacing Skills

Pacing skills can protect you from bonking. The faster you cycle, the quicker you burn carbohydrates. As a result, by starting faster than your desired speed and putting “time in the bank,” you’re burning through your carbohydrate storage quicker, and you’re likely to run out of fuel and bonk. Practicing your pace regularly is crucial if you want to give your best in a race.

Improving your capacity in pacing isn’t easy. You’ll need to devote yourself to practicing. As Malcolm Gladwell describes in Outliers, you just got to practice — it’s that simple. When it comes to running, learning to pace oneself isn’t easy. To acquire an intrinsic feeling of pace takes countless hours on the road and circuits around the track. Here are a few pointers that might be useful:

Learn To Be Patient

Rome wasn’t built in a day. Likewise, your pacing skills, acquiring these skills will take time, effort, and devotion. Pacing can be challenging to control, but it’s a necessary skill for racing faster and improving your fitness. The critical quality to achieve pacing is patience.

Use a Bike Computer

A bike computer, such as Garmin or Wahoo, is an excellent tool. This helps cyclists keep track of their pace while looking for ways to improve. You’ll notice a significant improvement in setting a consistent pace using a bike computer.

Garmin Edge 530 Bundle

Wahoo Elemnt Roam

Monitor Your Breathing Patterns

To assist you in feeling the speed, keep an eye on your breathing patterns. After you’ve settled on your workout’s target pace, pay attention if you start breathing quicker or your breathing rhythm changes to see if you’re speeding up or slowing down by accident.

Keeping tabs on all your gradual improvement plays a critical role in preventing you from hitting the wall.

You’re Low on Energy and Need To Refuel

When you happen to be cycling and bonking, it can also mean that your body is low on energy and you need to refuel as soon as possible. Riding without prior meals and hydration isn’t recommended, and you may find your energy levels depleted quicker.

When your energy levels are running low, refuel, but stick to your plan. Start with items that release energy quickly, such as dried fruit, a very ripe banana, an energy bar, or a couple of swigs of an energy drink. If you haven’t been keeping hydrated, you could be in big trouble.

Prevent Running Low on Energy and Hydration

To prevent your body from running low on energy and eventually bonking, you need to ensure you’re adequately hydrated and have enough carbohydrates and proteins to keep you going. Reduce the amount of stress on your body by slowing down and allowing any food to digest.

If you recognize the warning signals of a coming bonk, you can avoid it if you respond quickly and haven’t fully depleted your reserves.

While it’s good to bring food and drinks with you to refuel on, you don’t want to ingest too much in one sitting. Doing so will only hinder your digestion and overburden your stomach and gut, which can make subsequent riding more uncomfortable. Only eat what your body can accommodate and utilize. 

Stay adequately hydrated and snack on carbohydrates while riding.

It’s best to portion out your snacks beforehand and check out the carbohydrates of each snack as well. Avoid fatty, greasy, and unhealthy snacks, such as candy, chips, and anything fried. 

When you’re refueling while riding, you usually won’t need an entire meal, just enough to get your energy levels back up and running. If you’re going on a longer ride, you may need to plan for more than one refueling session, depending on your physical needs. If this is the case, pack a variety of snacks that can help you refuel, such as oats and fresh fruit.

Remember to be prepared, follow your rules, strictly drink and eat when you’re supposed to, and you’ll see yourself finishing the race in one piece. You can finish the race in good shape with proper fueling as you feel better and recover your balance.

Bonking can be avoided if you anticipate and plan for it and keep a regular carbohydrate intake before and during your ride, ensuring you pace yourself during the ride.

While bonking to a novice may suddenly feel like the end of the world where everything comes crashing together, and there’s absolutely nothing you can do, it always helps to keep the above points at heart. 

Preparedness, including pacing, feeding, and continuous refueling during the race or competition, will eventually help you push through and gladly finish the race you started. Don’t forget; it can be a dangerous and ineffective event, so your first objective should be to recover safely and get back on track.


Bonking happens to all cyclists, but it can be avoided with the proper carbohydrate intake, energy bars or gel, and adequate hydration. Loading the body with enough carbs before an event will help a cyclist keep a balanced pace. 

Pacing is a critical skill that protects cyclists from burnout. When training for a race, be cautious of your pacing to avoid burning out too quickly.

A great strategy will only give you success, so before the event, feed well, improve your pacing, refuel while on the move to prevent “hitting the wall.”

Other articles you may find interesting:

11 Tips for Overcoming Cycling Fatigue

How To Lose Weight Without Losing Cycling Power

12 Best Foods To Eat When Cycling Long Distance

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