Anne Truong MD explains why anxiety kills erections: your sympathetic nervous system triggers fight-or-flight, which tightens penile smooth muscle. Relaxation and parasympathetic activation do the opposite, letting blood flow in.
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It all starts in the brain. And so when you start to have emotions that involve negative thoughts, that's going to dampen the whole cascade. It's okay if you feel that your penis go from less stiff than not. Because when you have an erection, you want to be in a relaxed state. You want to be in the feed or breathe nervous system, which is called pain. Parasympathetic nervous system. And the parasympathetic nervous system is what make your penis muscle relax. So that way you can have an erection. And so when you start feeling negative thoughts, and you start feeling panicky, whether you're going to be firm enough or whether am I going to be able to form this time, you start thinking about some negative thought, which then stimulate the sympathetic nervous system, which is the fight or flight system, which then will cause your penis to be flaccid.