Sandra stands at the edge of the precipice. She looks down. Is she sure she wants to do this? Her heart is racing. Her knees are weak. Everything in her body tells her STOP. And Sandra doesn't get any closer because she is standing at the top of a literal precipice and getting any closer would risk death. A slightly better view is not worth the danger. Sandra has a great adrenaline rush of terror.
Sandra stands at the edge of the precipice. She looks down. Is she sure she wants to do this? Her heart is racing. Her knees are weak. Everything in her body tells her STOP. But Sandra jumps because she is at an amusement park and a bungee chord is firmly attached. Sandra has a great adrenaline rush of excitement and has a great time.
What is the difference between Sandra's two experiences? From the perspective of her lizard brain, absolutely nothing. But to the higher thinking brain, there is a very large difference. Logically we can see that bungee jumping is much safer than being reckless around the edge of a cliff. But the lizard brain can't see the difference. It thinks it's going to die in both situations. This is why Sandra's body's physical response is the same to each. The lizard brain's job is to freak out at everything because it's a dangerous world out there and if you hesitate you might die.
Let's try another scenario!
Harold stands at the edge of the crowd. He looks out. Everyone is staring at him and only him. His heart is racing. His knees are weak. Everything in his body tells him DANGER. And for good reason. The tribe is mad because Harold stole his neighbor's food and they are confronting him and about to kick him out of the tribe. Excommunication from the tribe means Harold will probably die from being eaten by a lion because this is like 10,000 years ago. Harold has a great adrenaline rush of terror.
Harold stands at the edge of the crowd. He looks out. Everyone is staring at him and only him. His heart is racing. His knees are weak. Everything in his body tells him DANGER. But for no particularly good reason, as he's about to give a talk at a local programming meetup to boost his authority in his chosen technology and increase his networking opportunities. The tribe is happy because Harold has graciously agreed to speak and the meetup organizers are overjoyed to have him fill their speaking slots. Harold has a great adrenaline rush.
But what kind of adrenaline rush does Harold have?
I've heard it said that people often rate fear of public speaking higher than fear of death in surveys. What's so scary about public speaking? I'm not sure how completely correct this is, but I've heard it said that the only situation the lizard brain would find itself in where a bunch of people are staring at it is the "you are in big trouble" situation. And so lots of people staring at you literally causes the same fear of death response whether you are in trouble or you are giving a talk at a meetup.
But consider again the first scenario. The exact same physiological response of an adrenaline rush can happen in a dangerous situation or an exciting situation. The lizard brain doesn't know the difference, and so defers to the thinking brain to know if terror or excitement should be had.
The key: reinterpret nervousness as excitement
This bit of advice to reinterpret nervousness as excitement has helped me a bunch in my own public speaking and talking giving career. Consider that some people pay good money to experience an adrenaline rush in the form of bungee jumping, jet ski riding, and other forms of daredevilry.
You can experience this same excitement for free by giving a talk at your local meetup! (Note that this technique also works for asking persons of interest on dates.)
You are not weird or alone in being nervous. From what I can tell, that feeling never goes away, even for seasoned public speakers! And I'm no expert, but I can say that after giving about 5 talks I'm starting to enjoy the excitement and energy that comes from giving a talk. And it certainly gets easier with practice. You can work your way up from giving a 5 minute lightning talk to a 15 minute shorter talk to a longer 45 minute to 1 hour talk and go as slowly as you need. Before you know it you'll be speaking at conferences.
All of which, by the way, is a great way to increase your authority and reputation as a freelancer or job seeker. Are you good at what you do? Well now there is 45 minutes of recorded video footage of you proving that you are. Don't have something to speak about? I bet that anything that you think is mildly interesting and seems obvious will for some in the audience blow their mind.