I had a colonoscopy without sedative earlier today. It was quite tough and I had to take gas and air on a few occasions. My procedure lasted 45 minutes (large polyps removed and extensive examination). Although very uncomfortable, it was brilliant being able to chat with the medical team during operation and observe the procedure on the monitor whilst fully alert. It is worth noting that the doctor has asked me to ensure I have sedative option next time as spasm caused some difficulties on navigating colon. Also I think I would have opted for it anyway. It all depends on your pain threshold and how long you can cope. I could've managed 15-20mins but 45 was a bit much. Hope this helps and stay positive...