We cannot flee, thus, we have more of the fright mode. By the time we land, our hearts are racing, the respiratory rate is increased, and we are probably breaking into a sweat. If we did not sustain a serious injury, this extra adrenalin helps us get over the immediate effects of the fall. Of course, later, we are quite sore and fatigued, but grateful that nothing really bad happened. Fear is no fun, but dealing with it may build character.
Falls can result in serious injury or life threatening situations.
About seven years ago when I was leaving my office rather late one night, I fell on ice about midway between my office and my car. It was very cold. Because of the slippery ground, I was unable to get any traction, and could not get up. I was totally alone. I decided to crawl to my car.