Physically, a bonk is when your body is so depleted of energy if cannot keep you on your bike – or even keep you functioning and conscious. A bonk begins when both your blood sugar and the glycogen stored in your muscles and liver are gone. Your body tries to burn fat, but can’t turn it into energy quickly enough. You simply run out of fuel and your body shuts down.
But it’s not just glycogen depletion. There are 3 kinds of bonk :
1. GLYCOGEN BONK
You can be drinking gallons of water, but if your body doesn’t have enough fuel to run, it stops. Eating fruit or an energy bar can get you back in the saddle.
2. ELECTROLYTE BONK
Electrolyte depletion occurs when you sweat out all your body’s necessary minerals. You know this kind of bonk is happening when your heart has an irregular beat and you have a mineral taste in your mouth. For rides longer than two hours, you should fortify yourself with a quality highcarb sports drink and energy gels and bars or other foods that contain nutrients and minerals. This kind of bonk can put you in the hospital. You’ve depleted the minerals that regulate your body’s functions; muscles contract, breathing becomes ragged, kidneys shut down and you pass out. Repeated electrolyte bonks can permanently damage your kidneys.
3. FATIGUE BONK
You’re just too weary to push on. You’ve had enough to drink. You’ve eaten plenty of energy bars and your fingers are sticky from gel packets, but your legs have gone on strike. There’s no solution, aside from one to three days of rest. Then build up your dies times gradually again so you can condition yourself to cope with the same demands in future.