Ache

Do you ever feel that exigent need to do something completely life-threatening and dangerous? You get the thought in your head that you aren't alive, and you have to do something - anything - to wake up. You're just there, a small, insignificant creature waiting to break out of that shell.
I feel the craving for adrenaline almost daily. What could I do?
What if I hit 120 on the freeway, swing the steering wheel and yank up the emergency brake? What would happen then? Would I just stop? (Doubtful, considering the speed.) Would the car roll like a bouncy ball? Would I hit other cars? Would I even survive? If I knew the answer to that question, I would've already experimented.
Give me anything. Skydiving or bungee jumping. Swimming in a cage surrounded by sharks. Cliff diving. Revving the engine to my 600 bullet bike. Flying a jet. Being thrown from a two-ton raging bull. Punching out the irritating girl in my class. Running until my legs give out. Hang gliding or parachuting. Anything.
I often feel that aching need for the rush, the thrill of feeling "alive." Is it healthy to feed such a hunger? Or is it better to sit in silence as the ache intensifies? How far can I go? How much can my brain and body take? How far can I run? How fast can I do? How thin can I get? How long can I go without sleep? I find myself stretching my limits. Usually the fear overcomes the rush, forcing me to abandon before hitting my mark.
What can satisfy?