Coldwater_Canuck
Contributor
The problem with a short course and a short book are that a lot of subjects are never covered in sufficient detail. This is a perfect example.
When diving while congested, you may not be able to equalize on the way down. But even worse, would be if you could equalize on the way down you may not be able to equalize on the way up (reverse block), and end up doing horrible, amazingly painful damage to your sinuses and/or ears. If your lungs are full of goo and aren't efficiently exchanging gas, there's no telling what sort of interesting damage you could cause.
Because the classes are short and the cert agencies don't want to go into too much gory detail in OW class, "Don't dive while sick" is a good rule, just as is the depth limit for OW divers.
Terry
A bit off topic I guess, but isn't the risk basically if you need to take a decongestant to equalize and it wears off? That's the impression I got after reading a few different places, that if you were able to equalize on the way down, unless on some sort of medicine, the way up should be no issue.
I know when I was flying with a cold (worse than anything I've dove with) ascending to the first 10,000 feet or so (which is around the point they start pressurizing the aircraft) my ears were fine. However, descending from this point, my ears started killing me and my hearing was screwed up for days, it was horrible. But yet nothing on the way up.