For starters, here is a general orietation to diving with diabetes. It's from one of my past Rodale's "Ask RSD" columns:
"Are there restrictions to diving with diabetes?" W.A., Bozeman, MT.
Diabetes, along with asthma & seizure disorder, ranks among the most controversial medical conditions affecting divers. Diabetes was considered by many in the medical & dive community as a contraindication to scuba until opinion began to change in the early & mid-1990s. At present, the Undersea & Hyperbaric Medical Society and the YMCA have detailed protocols for approving diabetic divers, and British Sub-Aqua Club allows certification with clearance from a medical referee. DAN is currently conducting an extensive study of diabetic divers, and additional guidelines will very likely result. In addition, there is an outstanding dive program for diabetics age 17 and older, Camp DAVI (Diabetes Association of the Virgin Islands) located on St. John. It is operated by the University of the Virgin Islands and has diving diabetologists on staff, some of whom have the condition themselves.
As you know, the body uses the sugar glucose for fuel, and the hormone insulin is necessary for cells to metabolize it. In diabetes, the pancreas fails to secrete enough insulin, or the body's cells resist entry of insulin, and glucose builds to dangerous levels in the blood. The immediate result is cells are temporarily starved for energy, while over time damage to the eyes, kidneys, heart or peripheral nerves can occur. Signs and symptoms of diabetes can include intense hunger, thirst and tiredness, as well as weight loss, frequent urination, blurred vision, and even seizures and coma.
For the diabetic diver, the most worrisome immediate risk is blood glucose falling to a level where hypoglycemia, or low blood sugar, is precipitated. This can result from events such as too much insulin, alcohol or exercise, or too little or improper eating. An episode can cause weakness, tremor, sweatiness or chilling, irritability, alterations or loss of consciousness, and convulsions.
The diabetic must also be aware of the possibility of hyperglycemia occurring when insulin runs low enough that the body breaks down stored fat for energy. This process can eventuate in breathing difficulty, alterations or loss of consciousness & shock. If left untreated, both hypo & hyperglycemia can result in death.
While the criteria for clearance to dive differ among agencies, they generally include such things as a demonstrated understanding of diabetes, awareness of when a hypoglycemic episode is imminent, good control of the disease with no severe episodes within the past year, and no related abnormalities of the eyes, kidneys, heart or nerves which pose an additional risk. Some protocols include depth limitations to those above which nitrogen narcosis is likely to occur so as to avoid confusion of this phenomenon with a life-threatening hypoglycemic episode.
Clearly it is unwise to deny or minimize this condition to yourself, or hide it from your instructor or the ops with which you dive. If you have diabetes and want to dive, or are already diving without medical clearance, it is critical that you consult a physician to obtain an appropriate medical work up & permission to dive. Even after clearance to dive, it is prudent to carefully monitor blood glucose throughout the course of the dive trip, especially prior to a dive. Measurements at 1hr, 30min & 5-10min prior to a dive would not be excessive. Finally, bring on board whatever substances you use for controlling abnormal glucose levels, and make sure your dive buddy also carries & knows how to use them."
The YMCA diabetic protocol can be veiwed here--->
http://www.ymcascuba.org/ymcascub/diabetic.html
DAN & BASC guideline can be viewed here---->
http://www.scuba-doc.com/endmet.html#Diabetes_and_Diving
As regards tech diving in particular, I know of no studies that have this as a primary focus. Of course, the increased physical & psychological demands of tech diving, along with the increased inherent risks, could suggest that a higher standard be applied.
Hope you found this informative.
DocVikingo
