DAN Medical Frequently Asked Questions

Diving With Hyperglycemia

The importance of re-evaluating your fitness to dive.I am scuba-certified but I've been out of diving for the past 10 years. In that time, I've developed hyperglycemia (diabetes controlled by oral medication), and take medication daily to control my blood sugar. My dive instructor suggested I contact DAN for recommendations about diving on oral hyperglycemic medication. I am in good shape and jog four to five miles five times a week.

Getting re-evaluated before going back to recreational scuba diving is an excellent idea. Re-acquaint yourself with the proper skills and knowledge of safety practices, and get a fitness-to-dive evaluation to reduce the risk of a scuba-related injury. You didn't state whether you ever experience episodes of low blood sugar (hypoglycemia). Many people with diabetes have periodic hypoglycemia when they are taking oral medications, particularly during or after exercise. This is more common when using the longer-acting oral agents. Episodes of hypoglycemia do pose a risk for scuba diving.


Extremely low blood sugar in divers with diabetes can cause loss of consciousness. If this occurs while the diver is in the water, it can be fatal. It would be wise to obtain blood sugar measurements before and after your jogging sessions and after swimming. If hypoglycemia does not occur, and your physician advises you that you have no coronary artery disease or other reason to avoid scuba, you could resume diving. A regular annual re-evaluation for diving fitness is appropriate. If you do take up diving again, this would be an opportunity for you to learn how your blood glucose levels change with scuba diving. In DAN's current study of insulin-dependent divers, we require divers to check their blood glucose levels at three separate intervals before getting into the water and immediately after a dive. This additional information will help you make diving and eating decisions.