What you need to know about 'bonking' and how it can affect you during endurance sport
Bonking can affect anyone, regardless of fitness levels...
CapeTalk's Lester Kiewit speaks to Registered Dietician, Marie McGregor, from the Sport Science Institute of South Africa.
Listen below:
Ever heard of bonking? Let's get into it.
The primary cause is insufficient carbohydrate intake before, during, and after prolonged exercise, especially in endurance sports like marathons, cycling, or triathlons.
When glycogen stores (carbohydrates fuel) in the liver and muscles are significantly depleted, it leads to a sudden inability to continue pushing through intense exercise.
Common bonking symptoms include extreme fatigue, dizziness, nausea, weakness, and the feeling of being unable to move, McGregor explains.
Bonking can affect anyone, regardless of fitness levels, she says.
"How your body works when you are doing an endurance race is that it needs fuel to keep going, and when you are doing something like running for example, it's at a higher intensity and your body's preferred fuel is glucose... you get glucose from taking in carbohydrates, the carbohydrates you eat get broken down into glucose so you consume glucose, it goes into your bloodstream and you have glucose in your bloodstream."
- Marie McGregor, Registered Dietician - Sport Science Institute of South Africa
"Your body also stores glucose in the form of glycogen in your muscles and in your liver so when you are training and eating... between training sessions, you maximise your glycogen stores then when you are running, your goal is to keep these glycogen stores full and going so you continually have fuel available. So, what happens is that you have about 90 minutes of fuel available if your fuel stores are full that you can go. If you don't replace fuel during this time, your glycogen stores run out, your fuel stores run out and what happens is bonking."
- Marie McGregor, Registered Dietician - Sport Science Institute of South Africa
McGregor explains how bonking may have mental effects too.
"Glucose is one of your preferred fuels for your brain as well... so if you run out of glucose, your brain has also run out of its fuel that it needs. What often happens in these long races, which can contribute and exacerbate it is dehydration - which also leads to mental confusion, so it can be a whole combination of all these things."
- Marie McGregor, Registered Dietician - Sport Science Institute of South Africa
Scroll up to the audio player to listen to the full conversation.