Before you faint due to vasovagal syncope, you may experience some of the following: Pale skin Lightheadedness Tunnel vision — your field of vision narrows so that you see only what's in front of you Nausea Feeling warm A cold, clammy sweat Blurred vision During a vasovagal syncope episode, bystanders may notice: Jerky, abnormal movements A slow, weak pulse Dilated pupils