A real hit isn't just a flat feeling or tired legs. It's a total inability to continue, marked by nausea, extreme physical weakness, lack of coordination, and a deeply horrible feeling. Essentially, “bonking” is exercise-induced hypoglycemia or low blood sugar. That's when you need to stop every 100 m to slow your heart rate and deal with dizziness.
When 2 km from home you feel unreachable. I also remember excessive saliva and extreme hunger. Often, people associate the word bonk with hitting the wall during resistance events. For endurance athletes, it's a sudden and overwhelming feeling of running out of energy.
You were running or riding at what seemed like a manageable pace, and then, apparently, without warning, your legs turned to cement. With heavy legs, a feeling of fatigue all over the body, and sometimes dizziness, you are forced to stop. Hitting, or hitting the wall, is a term that most athletes recognize. While it's not something everyone experiences, when you hit, you'll know.
It's unmistakable that the feeling of severe weakness, fatigue, confusion, and disorientation is something you don't want to experience more than once. Knowing your body and paying attention to how you feel is more important than simply eating and drinking on a schedule. This ability to effectively recognize what is different from your normal situation or feeling could prove to be a lifesaver. But what should you do if you feel very sick during a trip, perhaps experience symptoms that are more extreme than usual, or even totally different from anything you have experienced before because of the same level of effort? The word “really” is the operative phrase here, but it's important to try to define for yourself what feels typical or normal versus what feels abnormal during a trip, since you're ultimately the best judge at discriminating between the two.
I thought I had a “little blow” once when I went from feeling in the best shape of my life to having absolutely no power after a corner. The feeling is said to be similar to taking a blow to the head (a blow to the head) and being eliminated from the competition. The important point to remember in these situations is that anyone can experience a shock while driving, but if you really feel unwell, and especially if any of the above symptoms are also present, you should immediately stop riding and seek medical attention. You hit yourself while driving, if you feel sick afterwards, are just lingering effects of glycogen depletion.
Basically, I will be sailing at 18 MPH on the plains and all of a sudden my speed will drop to 12 MPH for what seems like the same effort. If it happens to you, prioritizing a large carbohydrate intake in the first few hours is essential and then you should keep your training intensity low, while you snack between meals, for a day or two until you start to feel like you're back where you need to save energy. There may be a finer balance to achieve with shorter endurance events, such as those lasting less than a couple of hours, where the trade-off with feeling “heavy” at first may not pay off later on.