Fear of heights- scared I may jump- anyone else?

i feel the same a lot, like when i'm sat at the front of the bus i have an urge to open the doors and jump out when it's moving. i think it may be realated to the fact that are bodies haven't changed in time yet the way we live has and we don't face the danger we once did so there's a lot of built up testosterone and adreneline which wants to be released and these situations provide that satisfaction