Hi. I'm 31 years old man, I almost collapsed yesterday after running up and down in our building stair / staircase from ground floor to 4th floor 5 ups and 5 downs. I felt my ear was full and totally blocked. Then my eyesight gets dimmer every 2 seconds and becomes total darkness. I am sitting at my chair. Before I lost my consciousness, I called for help to my roomates. When I vomits, It started to get some light in my sight gradually. I drink water before and after running, but I did'nt took my breakfast yet. Why is that happened? Your reply will be highly appreciated. Thanks