I was doing my cardio on a gym bike the other day and out of boredom tried holding my breath a few times for just 20 seconds. I was going at a good aerobic working pace where I was breathing close to my maximum and just under an anaerobic pace. I did the first 20-second breathhold, which was so short there wasn’t much time to feel anything, and immediately after, came close to Samba. The room started getting dark, I saw spots everywhere, and I felt real light headed. I just grabbed the bars hard and kept peddling. It was over as quickly as it started and there was no pain or anything. I wasn’t sure if what I thought just happened or not, so I did it. Same result!
It was freaky and cool all at the same time. I was like going on a little miniature drug trip, but at the same time, I was kind of freaked that I could have fallen off and been hurt. The scary thing was that it came after the breath hold. I could have easily pushed the breath hold to 30 or more seconds, and if I had I probably would have blacked out afterwards.
don