Hello and Welcome to ‘Ask A Doctor’ service. I have reviewed your query and here is my advice.P Probably bending may cause posterior semicircular canals dysfunction lead to Acute vertigo and pass-out. it may be due to vasovagal syncope or sinus bradycardia and pass-out. Until examination is done it is difficult to say what it is. you may to check for your pacemaker functioning properly or not , get it done vestibular apparatus function check for posterior circulation stroke etc. Avoid high risk activities, use tablet Vertin thrice a day for five days. Please consult your physician he will examine and treat you accordingly. Hope I have answered your query. Let me know if I can assist you further.