breathing problem - need help

[romdz]

My dive buddy is experiencing the following problem:
During the dive and the descent everything is perfectly ok. As soon as he reaches the depth of around 70 ft, however, he begins having breathing problems. After ascending above 70 ft again, everything goes back to normal.

Some points to consider:
1. He is an experienced diver. He has over 100 dives logged, diving 4 times per year.
2. The problem developed suddenly. He has previously dived at depths of 120-130 ft without experiencing any problems.
3. He is 43 years old and appears to be in good health. After having some heart tests done (stress, nuclear), the results came back normal. His cholesterol and blood pressure are slightly high, but still not too bad.
4. We eliminated the regulator (apex-200) as a reason. The 2 of us switched regulators between dives, only for him to continue experiencing this problem. I was fine.

Does anyone have and ideas as to what it could possibly be? Thanks.

Rom

 

[reefsong]

There are any number of reasons your friend might be experiencing sudden problems diving. That he just recently got a cardiac workup doesn't preclude other medical problems, including but not limited to pulmonary embolus, partial spontaneous pneumothorax, as well as new onset anxiety disorder (yes, this is possible, even though he has previously been to depths deeper than 70 and not had difficulties at that time). The best thing you could recommend to your friend is to temporarily stop diving until the reason is found and he can be safely cleared for diving.

 

[Northeastwrecks]

1. He is an experienced diver. He has over 100 dives logged, diving 4 times per year.

With all due respect to your friend, I would not consider a person with 100 dives who dives 4 times per year particularly experienced.

Since you've eliminated the reg and a medical exam didn't reveal anything, I'd question whether the diver becomes nervous when he goes deeper than 70 feet. I'd also inquire whether the conditions he is currently diving in are similar to those he has experienced before. It could be that more challenging conditions (darker, deeper, more current, or any other unfamiliar condition) are causing increased anxiety. Increasing anxiety can cause an increased breathing rate, which causes increased CO2 buildup, which can make a person feel short of breath.

Finally, I'd ask whether the dives are different. Is the diver working more for some reason, such as swimming faster or attempting a particular objective (raising an artifact, having timed objectives). Once again, this could create an issue.