Here’s how to never “hit the wall” again

If you’ve been there, you won’t forget it—hitting the wall (sometimes called bonking) is an unpleasant experience familiar to many distance runners during training or racing. The term refers to the moment in a race or run when a runner feels suddenly and profoundly depleted of energy. The good news? It’s entirely avoidable. Here’s how to steer clear of the bonk.

The dreaded sensation of hitting the wall occurs when runners deplete their glycogen stores in the muscles and liver, the body’s primary energy sources during prolonged physical activity. While it commonly happens around the 25 to 30-km mark in a marathon, individual experiences can vary based on factors such as training, nutrition and overall fitness level.

As legs become heavy and pace slows, runners find themselves navigating through profound physical and mental fatigue. Elisabeth Scott, a Connecticut-based running coach and host of the Running Explained podcast, reassures runners that hitting the wall is not inevitable, and provides some key strategies to prevent this challenge.

Slow your start

With the adrenaline boost of a start line and legs fresh off of a taper, it can be very tempting to take off hot from the start. Scott says that going out with a more aggressive effort or pace than you have trained for (even if it feels sustainable at first) will rapidly burn through fuel stores and create excess fatigue. She suggests being extra conservative in the early stages of your race. “In most race strategy plans, you should aim to run slightly slower (5-10 sec/kilometre) than the average goal pace for the first few kilometres of your race,” explains Scott.

Build a strong base with adequate training

Make sure you aren’t heading into a race or long run without adequate preparation. “Lots of easy effort running to build your aerobic capacity, plenty of weeks of training to prepare properly and lots of long runs to also help practice your fueling strategy,” says Scott. “Not giving yourself enough time to prepare for the demands of your chosen event can lead to being ill-equipped to deal with the physiological demands of running for hours at a time.”

Carb load and fuel well

“Two to four days of carbohydrate loading (eight to 10+ grams of carbohydrate per kg of body weight per day) in the days immediately preceding your race can increase glycogen storage and improve race day performance by two to three per cent,” Scott says. Making sure you eat enough in the days before your race is key to helping your body power through to the finish. During your race, most experts recommend taking in about 60 grams of easy-to-digest carbohydrates per hour during a marathon. Make sure you are hydrating appropriately, taking into account factors like the temperature of the day.