There are always people who fail at swim lessons just like anything else, it's more that. It's a tough problem to solve. I have no more than 10% body fat, I h

There are always people who fail at swim lessons just like anything else, it's more that. It's a tough problem to solve. I have no more than 10% body fat, I have no issues. But I also taught adults who were similarly low body fat and some I succeeded in teaching and some I did not. Consciously controlling your breathing is a big deal in many aspects of swimming & diving. It has a major effect on buoyancy. You can't breathe normally/unconsciously swimming/floating. It is always controlled. Likewise you must keep breathing when diving with compressed air.