Hi dub --
I'm a fat woman diver! Welcome to the club.
First, my disclaimer -- I am not a medical person, and this is not to be construed as medical advice.
There are primarily two issues that are special to fat folks (as has been discussed already) I may be repeating what was said, but perhaps I'll say it in a slightly different way.
The first issue is aerobic fitness / cardio vascular health. Diving is a sport, you do need to be able to demonstrate some physical stamina. Minimally, you'll need to be able to swim 200 yards without stopping. (no gear). One way of thinking about it that I have used with my friends is -- you'll need to be able to put on the gear and carry is around to do a beach entry. (now, technically, you could do only boat diving and could put your gear on in the water --) but, for reasonable-ness sake -- I usually say -- think about putting a 40 - 50 pound back pack on and walking a city block. That's a guideline that I use -- it's not a perfect test, but at least it gets you thinking. Of course, the better fit you are, the easier it will be to master the required skills, the more comfortable you will be in the water, and the better your air consumption will be.
OK, the second "biggy" is Decompression Sickness (DCS) or "the bends". This is what was referred to earlier regarding Nitrogen. The air that we breath is comprised of Nitrogen and Oxygen (and other stuff in smaller quantities) When we breath that air under water, it is compressed (under pressure) and some of the nitrogen is dissolved in our bodies. If that nitrogen comes out of solution in our bodies too quickly, bubbles are formed and that is what causes "the bends". We don't know exactly why some people get "bent" and others don't in the same situation, but we do know things that seem to increase the risks.....
Age -- older people seem to be at greater risk than younger
Gender -- women seem to be at greater risk than men
Fat - larger percentages of body fat seem to be at greater risk
Aerobic fitness - less fit people seem to be at greater risk
Alcohol consumption before or after the dive may increase the risk
People suffering from fatigue are at greater risk.
There are others, but that's what comes to mind.
OK, I am a 40 year old fat broad.... but, I'm not going to give up diving -- so what can I do to minimize my risks?
I want to be in the best possible fitness I can.
I want to stay as well hydrated as possible (dehydration is a risk)
I want to stay as well rested as possible.
I want to always dive conservatively -- that means that I watch the tables or my computer carefully -- always staying well within the 'no deco' limits (you'll learn about this in class) -- In fact, my computer has an adjustment, so that I am able to choose a more conservative algorithm.
I can make sure that I ascend slowly from every dive. (you'll learn about this too.)
And, I make sure I always take a safety stop, 5 minutes or longer.
For me, diving is a life affirming activity - I won't give it up... so I try to mitigate the risks... just like I try to look both ways when crossing the street, and always where my seat belt when I'm driving.
I'd love to chat with you privately -- pm me if you want.
Also, you might want to check out my website, where some of the other concerns for fat divers are discussed.
www.bigadventures.net
Liz