Posted by Kendall Raine on September 25, 2001 at 12:54:54:
In Reply to: Re: Dive Computers-Really Long posted by Jon D on September 25, 2001 at 11:21:41:
Hi, John;
All of what you are doing to reduce risk should reduce risk. You're right, they're no guarantee but you are lowering your decompression stress. The physical fitness part gets little attention on this Board and your taking up mountain biking is a great way to strengthen your legs, lower body fat, improve the cardio and boost your confidence. Deco efficiency is correlated with fitness for several reasons.
There are many ways to become more aware of deco status. The first is how do you feel after the dive? Are you sluggish, tired and fluey or are you ready to rock? Can you go to the gym after you get home, or jump on your mountain bike and perform, or do you just want to go to bed? How you feel is the best indicator of how you're dealing with deco stress.
The second way is to read up on the subject. I don't mean Alert Diver, either. There are some good reference materials out there and some web sites that deal in pretty cutting edge stuff from people who actually know something about the subject. Understanding the issues with ascent rates, bounce diving, sleep, hydration, fitness and myriad other variables will feed into your pre-dive planning. The more you start thinking about this stuff, the more you'll naturally start using your computer more and more as a bottom timer. That's a natural and safe evolution.
The third is get a PC based software program and play with it. I think Decoplanner is about $90. Cheap! By playing with the model, you get a sense of how the variables behave. It's still just a model, but it works.
Another way is you could buy and learn to use a Doppler ultrasound. That'll give you an indication of decompression stress by measuring the magnitude and duration of post dive bubbling. The magnitude and the time for bubbles to clear are measures of your deco efficiency. That's an expensive proposition, however, and it takes a while to get good at using the thing. For the diving you do, I'd only suggest that if your a closet freak for this stuff.
Lastly, you could get yourself checked for a PFO or septal shunt. Bubbles are brought to the heart from tissues via the veins and sent to the lungs where they are filtered out by capillaries. If you have a hole in the heart, those bubbles can short circuit the trip to the lungs and get into the arterial system whence they can find there way to the brain. This is bad. The test is expensive and not without some risk. I suspect most diving docs would encourage you to dive conservatively and skip the test. Your choice.
T