A car accident can cause an adrenaline rush. The wreck is frightening, sudden and traumatic. Your body reacts instinctively, and you have nothing to do with this chemical process.
The downside to an adrenaline rush is that it can mask pain or make it harder to feel injuries. It doesn’t do this the same way that a painkiller does, but it helps your body function through the pain. People often do not realize that they have been injured until the adrenaline rush is long over and they start to feel the effects.
This can keep people from seeking proper medical care. The EMTs who come to the scene may ask them if they are injured or if they want to go to the hospital, but they may insist they are fine and deny that treatment. The next day, they’ll come to the ER with serious issues — brain injuries, internal injuries, etc — that went undetected.
Why does the body do this? The reason is that, from an evolutionary standpoint, adrenaline would help. It allowed those who had been injured in accidents or by predators to keep fighting or running. This saved lives. It was beneficial to humanity. If someone just collapsed from the pain, they would die.
That helped 10,000 years ago. Today, though, it could actually cause death by making someone overlook a serious injury and reject the very medical care that would save their life. This is why it’s important to talk to a doctor after a crash, no matter how you feel. If it turns out that you are injured, you may be able to seek financial compensation for your costs.