If someone is pulled into the water unexpectedly, and so maybe did not a get a good breath of air, how long would they remain conscious for before passing out?

Depends how much air they have in their lungs and how much their body needs….

Why, you planning on drowning someone? Don’t answer that, I don’t want to know.

Depends on their lung capacity,age,experience,healthiness,and their ‘will’ to survive.

One to 3 is typical I have seen swimmers stay conscious underwater over the 6 minute mark. I used to be able to do 3½ mins not anymore. 2½ is about all I can squeeze out.

“An average person in good health can hold his breath for about two minutes, but with even small amounts of practice it is possible to increase that time dramatically.”

Time

I think you can hold your breath longer if you are completely calm and relaxed. However in a panicked state, the adrenaline rush would happen and your heart would be pounding pretty fast and hard. I think that would increase your oxygen needs.

Well, it depends. So I will just pretend the person is 25, can swim but isn’t a great one, just average, doesn’t have medical problems and is fit. Oh, and they have just like a quarter of a full breath. So if they are calm probably 60 seconds till they pass out. If they are paniked then about 40. Then again, if just before they passed out they released all of tgeir breath then that would add about 10/20 seconds. So 2and a half minutes at best.

32.5 seconds exactly.

If you did not get a good breath. And, started to panic, you would probably start choking. Then you would start to suck water.

Not long before you black out.

Well I almost drown when I was little and never did loose consciousness. Made it all the way to the bottom of the Lake, just as I was being rescued. The strange thing as I look back now is there was no fight for air or survival on my part. I was so taken by all the underwater life I saw on the way down, completely awestruck by the beautiful fish and plant life. It was a wow moment, had no idea all that was under the water such a beautiful experience. It seemed to take a long time like slow motion.

Is this person a smoker? Smokers can’t last nearly as long as a non-smoker.

In terms of saving a person whom you have seen go beneath the surface, lung capacity is loosely based on these things:

Is it an adult or a child? The smaller the lungs, the less time they have before irreversible injury, or death, sets in.

Were they panicking? Sounds like a stupid question, but a great swimmer caught in a rip tide usually knows to stay calm. Panicking sucks up oxygen extremely fast.

What’s the water temperature? If its swimming weather, they’re screwed a hell of a lot quicker. If they feel through a sheet of ice on a lake in the middle of winter, the body uses up remaining oxygen almost by half (but figure for a third).

For a healthy adult, the window of opportunity closes between 4 and 5 minutes in normal temps. By 6 minutes, 99% of the time, we’re talking organ donor. For a child, cut it in half. Just because they are unconscious does not mean that they are hopelessly brain damaged, so hurry your ass up, already!! If you can reach them SAFELY, then use whatever is around you and help them. If you CANNOT be reasonably sure of your own safety, then absolutely do not proceed.

Without taking a deep breath? Neighborhood of 30 seconds.

We need a test subject to determine this experimentally. You volunteer?

we could have gladiators that go into the tank with a killer whale and see if they last 10 minutes.