Hi and welcome to Healthcaremagic. Thank you for your query. I understand your concerns and I will try to help you as much as I can. Your condition is so called micturition syncope or post-micturition syncope which is benign issue which is a result of vasovagal response, postural hypotension. People often become pale, lightheaded, nauseated, sweaty and weak before they lose consciousness. Sometimes defecating, coughing, or severe vomiting may cause fainting in a similar way. There is no specific treatment for it and only if this happens frequently you can: sit while urinating, sit on the edge of the bed for a while before getting up and going to the toile, avoid urinating while sleepy, urinate before sleep. So this is not directly related to urine or bladder but more like neurogenic response and there is no need to be worried. I hope I have answered you query. If you have any further questions you can contact us in every time. Kindly regards. Wish you a good health.