When I was going through Jr. Lifeguard training back in 6th grade, I had to be able to hold my breath for as close to three minutes as manageable. I was able to hold it for about 2 minutes and 46 seconds. No clue how long now, but in Duluth, there is a series of four tunnels that I can still manage to hold my breath through going at about 30mph. Speed limit is 55 and people have troubles at that speed. So, better than average still.