I was wondering if it's normal to blackout during sex. It only happens when I'm stand up or when I'm in the shower. My vision goes grey and everything starts spinning my hearing starts to go and everything sounds muffeled and my legs go weak. The last time it happened my girlfriend said I was shaking and I don't remember any of it. If I set down I recover from it but if I don't I blackout. Im fine laying down just when I stand it gets to me?