I had been doing the Wim Hof method of breath work and cold plunging and I think I might have been pushing it a bit far on the breath work because I was passing out regularly. 

I did it at work once and checked my oxygen saturation and it went really low, like less than 50%, but I felt fine. I think sometimes when I did it at home, I would have been profoundly hypoxic leading to the loss of consciousness. Nothing generally happened and I would wake up with no effects. But once, I had what I thought of at the time as a 'vision.’ Now I think it might have been an NDE. 

I must have passed out and the next thing I knew, I woke up and I was floating through a vast black space with nothing around me. I had no control over where I was going; I was just floating, almost like I was being taken somewhere. It didn't even occur to me to try to control where I was going.

I could hear strange, discordant and quite spooky sounding chimes playing, not like anything I’ve really heard before. But it sounded something like religious/church music. It was quite an unsettling feeling, particularly as the chimes were almost scary. It was such a weird sound.

Then, ahead of me I saw a portal, almost like a roundish hole in the black space. It was right ahead of me and I was floating towards it. Through the portal was something like a massive cave that opened up out of sight. There was a bright yellow light inside there. I couldn’t see where the light was coming from, but it was illuminating everything inside. 

As I got closer, I saw people sitting around on little rock formations on the other side of the portal. I wasn’t aware of knowing any of them, aside from the one person sitting nearest to the entrance. He was looking at me very attentively, like he had a question for me or was evaluating me. I had the strong sensation that if I floated through the portal, there would be some sort of profound information or message that I would receive. That I had a moral lesson to learn from his being there and looking at me like that. I felt he was showing me it was important that I made the right decision, which was obvious but personally very difficult to make.

But just at the moment I was about to enter the portal, I woke up on the floor of my bedroom and that was it. 

I’m not close to the person I recognized in the cave, but we have a mutual friend that we are both very close to. The situation with this mutual friend had been a bit complicated and quite upsetting. There was an important moral life lesson that I needed to learn in order to progress from the situation, which I have since done. Now I have the feeling that this experience I had was like a warning because there would be karmic implications for my behavior if I didn’t do the right thing.