Diabetes and Diving -

Diabetes and Diving

Facts and a Firsthand perspective from Rescue Diver Cody Hartman, ESQ.

Article by Nurse Nancy Huntington-Grahn

The Facts – Section 1
Considerations for Scuba Diving with Diabetes – Section 2
Cody Hartman living and diving with Diabetes – Section 3

The Facts

Globally, it is estimated that approximately 537 million adults are living with Diabetes type 2 (2021 data from the International Diabetes Federation). I personally am not a person living with diabetes, but as a nurse educator, I have cared for many patients with this chronic condition. As an SDI Instructor Trainer, I have taught several students living with diabetes, classes from open water to professional level certifications. I invited a former student – Cody Hartman, Attorney / Rescue diver to assist me in coauthoring this article, where he gives a first-hand perspective on diving with diabetes.

Glucose: C6H12O6 -> 2 hydrogen atoms for each carbon and oxygen atom in the molecule-> (sugar) mainly comes from your carbohydrates in your food and drinks. Glucose is your body’s go-to source of energy, and your blood is responsible to carry glucose to every cell to use for energy. When glucose enters your bloodstream, it essentially needs a “conduit “to reach the body’s cells. The “conduit” is insulin (a hormone) and if the pancreas is not making enough insulin or isn’t using it properly, glucose will build up in the blood stream.

Diabetes- Type 1 is an autoimmune condition whereas the body does not produce insulin. Type 1 is often diagnosed early on in life.

Diabetes-Type 2 is a condition that happens when your blood sugar (glucose) is too high. It develops when your pancreas doesn’t make enough insulin or because your body doesn’t respond to insulin appropriately, a condition known as insulin resistance.

Symptoms:

Type 2 diabetes symptoms can vary and may develop gradually over time. Some common symptoms include:

Increased thirst: Feeling very thirsty, even after drinking fluids.
Frequent urination: Needing to urinate more often than usual, especially at night.
Increased hunger: Feeling very hungry, even after eating.
Fatigue: Feeling tired and lacking energy.
Blurred vision: Temporary vision changes due to high blood sugar levels.
Slow-healing wounds or infections: Cuts, bruises, or infections that take longer to heal.
Numbness or tingling in hands or feet: Loss of sensation or tingling in the extremities.
Weight loss: Unintentional weight loss, despite eating normally.
Skin problems: Dry skin, itchy skin, or skin infections.
Eye problems: Diabetic retinopathy, which is damage to the blood vessels in the eyes.

Causes: Insulin resistance: At the heart of type 2 diabetes lies insulin resistance. This condition means that the body’s cells, especially those in the muscles, liver, and fat tissue, become less responsive to insulin—a hormone produced by the pancreas that allows glucose to enter cells from the bloodstream. Initially, the pancreas compensates by producing more insulin, but over time, it can no longer keep up with the body’s increased demand. As a result, blood glucose levels rise, eventually leading to the diagnosis of diabetes.

Genetics: Genetics play a substantial role in the development of type 2 diabetes. Individuals with a family history of the disease are at a higher risk of developing it themselves. Many genes are involved in blood sugar regulation, insulin production, and response to insulin, and variations in these genes can predispose someone to diabetes.

Family History: Having a parent or sibling with type 2 diabetes significantly increases risk.
Ethnic Background: Certain populations, including people of African, Hispanic, South Asian, Indigenous, and Pacific Islander descent, have a higher genetic risk for developing type 2 diabetes.
Obesity: The most significant modifiable risk factor for type 2 diabetes is being overweight or obese. Excess fat, particularly in the abdomen (visceral fat), is strongly linked to insulin resistance.
Visceral Fat: Abdominal fat releases hormones and inflammatory substances that disrupt the action of insulin on cells.
Body Mass Index (BMI): Individuals with a BMI greater than 25 are at increased risk, with risk rising sharply at higher BMI levels.

Physical Inactivity: Leading a sedentary lifestyle contributes greatly to the development of insulin resistance and type 2 diabetes. Physical activity helps maintain a healthy weight, improves the body’s sensitivity to insulin, and supports healthy glucose metabolism.

Muscle Action: During exercise, muscles use more glucose, reducing blood sugar levels.
Weight Control: Regular physical activity helps prevent obesity, a major risk factor for diabetes.

Dietary habits: Pivotal in the development of type 2 diabetes. Diets high in calories, processed foods, saturated and trans fats, sugar-sweetened beverages, and refined carbohydrates all increase the risk. Conversely, diets rich in whole grains, vegetables, fruits, lean proteins, and healthy fats are protective.

Excess Caloric Intake: Consuming more calories than the body burns lead to weight gain and insulin resistance.
Sugar and Processed Foods: High intake of added sugars and highly processed carbohydrates can spike blood sugar and increase fat storage.
Low Fiber Intake: Fiber helps regulate blood sugar and improve satiety.

Age: Risk for type 2 diabetes increases with age, particularly after age 45. This is partly due to decreased physical activity, loss of muscle mass, and increased weight gain as people age. However, type 2 diabetes is increasingly being diagnosed in younger individuals, including children and adolescents, largely due to rising rates of obesity and unhealthy lifestyles.

Chronic Stress: Long-term stress can alter hormones such as cortisol, which in turn raises blood sugar levels and contributes to insulin resistance. Chronic stress can also lead to unhealthy behaviors, such as poor diet and physical inactivity, further raising risk.

Sleep Quality: Both sleep deprivation and poor sleep quality are associated with a higher risk of developing type 2 diabetes. Disrupted sleep affects hormone balance, increases appetite, and reduces insulin sensitivity.

Alcohol and tobacco use:

Excessive Alcohol Consumption: Heavy drinking can contribute to pancreatitis, which impairs insulin production, and promotes weight gain.
Smoking: Tobacco use increases insulin resistance and raises the risk of type 2 diabetes.

Socioeconomic and environmental factors: Access to healthy foods, opportunities for physical activity, education, and healthcare all influence diabetes risk. People living in low-income areas may face extra challenges in maintaining a healthy lifestyle.

Food Deserts: Areas with limited access to affordable, nutritious food make healthy eating difficult.
Lack of Safe Places to Exercise: Neighborhood safety and accessibility of parks or recreation centers affect physical activity levels.

Considerations for Scuba Diving with Diabetes

For individuals living with diabetes, engaging in physically demanding activities like scuba diving demands special consideration and preparation. The underwater world offers a sense of adventure, tranquility, and discovery, but it also imposes unique physiological challenges that can complicate diabetes management—especially glucose control. Fluctuations in blood sugar, the effects of increased physical exertion, and the unpredictable nature of open water environments require divers to be vigilant, knowledgeable, and proactive in their approach to glucose management.

Diving places unique stress on the body, and certain aspects of diabetes, particularly the risk of hypoglycemia (low blood sugar- typically below 70 mg/dl), can be exacerbated underwater. Factors that may contribute to unpredictable glucose levels include, but are not limited to:

Environmental Stress: Cold water, currents, and the mental stress of diving may alter glucose metabolism.
Altered Routines: Changes in meal timing, medication schedule, and sleep patterns can impact glucose control.
Pressure Effects: The pressure underwater can influence how insulin and medications are absorbed or metabolized.
Swimming increases energy use, potentially lowering blood glucose.

Medical assessment and clearance: Before engaging in scuba diving, individuals with diabetes should undergo a comprehensive medical evaluation with a healthcare provider

knowledgeable about both diabetes and dive medicine. A written medical clearance is often required by dive operators and is strongly recommended for personal safety.

This assessment should include:

Review of glycemic control history (ideally with recent HbA1c results)
Screening for diabetes-related complications, such as retinopathy, neuropathy, or cardiovascular disease
Evaluation of hypoglycemia awareness and frequency of recent severe hypoglycemic episodes
Assessment of physical fitness for diving

Glycemic control and dive planning: Well-controlled and stable blood sugar is crucial for safe diving. Divers should maintain good glycemic control in the weeks leading up to the dive and avoid diving if glucose levels have been erratic or if recent severe hypoglycemia has occurred. Divers are encouraged to establish personal thresholds for safe blood glucose levels before, during, and after diving (typically, pre-dive glucose should be in a safe, slightly elevated range—consult with a provider for individualized targets).

Meticulous planning reduces risks and ensures that contingencies are in place. Consider:

Choosing dive sites with easy access and reliable emergency services
Arranging short, shallow dives initially, especially if new to diving with diabetes
Ensuring all dive buddies are aware of your condition and are trained in basic diabetes emergency response (recognizing and treating hypoglycemia)
Packing extra glucose sources, blood glucose meters, and spare supplies in waterproof containers
Scheduling dives after meals to avoid fasting states and help stabilize glucose

Monitoring blood glucose: Monitoring before and after each dive is essential. While monitoring during a dive is challenging, new technologies—like continuous glucose monitors (CGMs)—may be helpful if properly protected from water and pressure. However, traditional fingerstick checks are not possible underwater, so divers must rely on pre-dive preparation and post-dive monitoring. Check blood glucose 60 and 30 minutes before the dive, and immediately before entering the water. If glucose is below the established pre-dive threshold, treat and recheck. If using a CGM, ensure it is calibrated and protected by a waterproof case if possible.

Carbohydrate supplementation: Carry fast-acting glucose sources (such as glucose gel, tablets, or high sugar snacks) in a waterproof container easily accessible to both diver and

buddy. Plan carbohydrate intake before the dive based on recent trends, meal timing, and anticipated exertion.

Consume a carbohydrate-rich snack 30-60 minutes before the dive
Have a plan for carbohydrate supplementation if a dive is prolonged or unexpectedly strenuous

Medication management: Insulin users may need to adjust dosing to prevent hypoglycemia. This often means reducing insulin for the period before and during the dive.

However, all medication adjustments should be made in consultation with a healthcare provider.

Consider reducing basal insulin dose for the day of diving
Adjust bolus (mealtime) insulin to account for scheduled activity and food intake
Review other oral diabetes medications with a provider to assess risk of hypoglycemia

Communicating with your dive buddy: Your dive buddy should be informed about your diabetes, the signs of low or high blood sugar, and what actions to take in an emergency. A pre-dive safety briefing that covers your condition, symptoms to watch for, and the location of emergency glucose is essential.

Post dive management: After resurfacing, promptly check blood glucose and monitor for delayed hypoglycemia, which can occur after prolonged physical activity. Have snacks and glucose sources readily available. Check blood glucose immediately after the dive and at regular intervals for several hours.

Monitor for symptoms of hypoglycemia, which can be delayed after physical exertion
Rehydrate and have a balanced meal
Record glucose readings and any symptoms to discuss with your healthcare team for future planning

Special considerations:

Do not dive if: Blood sugar is unstable, you have had recent severe hypoglycemia, or you have diabetes complications that may impair safety (e.g., impaired vision, significant neuropathy, or heart disease).
Always: Have an individualized diabetes management plan for diving, which is reviewed and updated regularly with your healthcare provider.
Carry: Medical identification indicating diabetes, in case of emergency.
Be aware: Environmental factors such as temperature, duration, and dive conditions may require adjustments in your usual diabetes management plan.

Advances and Technology: The rapid evolution of diabetes technology has brought new tools to the diving community:

Continuous Glucose Monitors (CGMs): Some CGMs are waterproof and can be used during diving but always verify manufacturer guidelines for depth and duration limits.
Insulin Pumps: Most insulin pumps are not designed for underwater use. Plan accordingly and disconnect if needed, following your provider’s advice.
Waterproof Carrying Cases: Specialized underwater cases allow for the safe storage of glucose meters, snacks, and other supplies during a dive.

Firsthand perspective from Cody Hartman living with Diabetes:

Having lived with Type 1 Diabetes for almost 30 years, I wanted to share some insight that may be helpful to get you diving with your Diabetes. Whether you are a Diabetic interested in diving for the first time, or have recently been diagnosed, I would first check in with your primary care physician or endocrinologist. Prior to your appointment, I would recommend reading up on published material about diving with Diabetes and write out a personalized plan on how you will manage your diabetes on a day of diving.

When I met with my physician, I provided a hypothetical timeline of a dive day, showing the times I would eat, types of food I would eat, times I would check my glucose, dive times, times I would administer insulin, the type of insulin I would administer and contingency plans. I also outlined how I would handle an emergency and how my buddy would handle an emergency (both in and out of the water).

Show your physician your plan and work together to address any concerns. Keep in mind your physician will have to sign of any medical waiver, so show them you’re prepared! In addition to keeping an up-to-date medical release in my dive log, I have a letter from my physician outlining that they are my physician, the date they last examined me, how long I have had Diabetes and that I have had no major Diabetic related issues.

I also keep a history of my Diabetes management, outline of past A1c and concluding that I am medically cleared to dive. This type of letter has saved me once in the past, and is also a nice item to have, particularly when traveling to other countries with Diabetic supplies (i.e. a lot of needles!). Another smart tip is to keep a copy of these documents on your phone and a copy in your email should you lose the paper copies.

As with everything involving scuba diving, we do it with a buddy. Diving with Diabetes is no different. Ideally your buddy will understand your personal Diabetes management practices. Educate your buddy well in advance of the dive. Have a copy of your plan and be prepared to discuss handling both hypoglycemia/hyperglycemias. Discuss hand signals that you may use to describe something is wrong, or that you are experiencing hypoglycemia.

For instance, I make the shape of an “L” (“L” equating to “low blood glucose”) with my hand across my forehead to describe to my buddy, underwater, that I may be experiencing a hypoglycemic episode. You can always also use the “something is wrong” sign and recommend surfacing. Though our mind always gravitates to the worst – having a low blood glucose while underwater, it’s very much more probable that we’ll have issues outside the water. Discuss with your buddy any key characteristics indicative of issues such as confusion, shaking, or sudden change of emotion. Discuss how to treat these types of concerns. My buddy and I also understand that I can end a dive for any reason, at any time.

Conversely, my buddy also has the right to end a dive, on my behalf, if he feels that I may not be in the best health. Though we primarily rely on our buddy in the water, if diving on a boat, I always tell the Divemaster about my Diabetes and let them know who I am diving with. When possible, I will also tell the boat Captain.

If the dive party is large enough, I will also inform the safety diver. If appropriate, or in a small group, I have even told other seasoned divers about my Diabetes, just to let them know. Generally, divers are a curious bunch and always love a free education! Many times, before I have found myself giving a full lecture to curious divers on the intricacies of diving with Diabetes while headed out to a dive site.

In every instance I have shared information with dive staff, they have been appreciative of me sharing. If you intend on going to a remote location to go diving, I recommend communicating with the dive company very early to understand their processes, concerns, and plans. Communicate with them to determine what medical documentation is necessary to dive with them, and any special areas of concern that they may have. The last thing you want to have happen is to travel to a far-off land only to learn you won’t get to dive for lack of medical clearance.

Diving and Diabetes can be a match made in heaven. Divers tend to be device nerds. Similarly, Diabetics can also be device nerds. All that to say, consider your Diabetes management supplies carefully. Ensure that you have enough supplies, batteries, insulin, and/or other medications to last. Redundancies are always key. When diving from a boat, I learned to bring two glucometers after my CGM failed and I foolishly soaked my glucometer.

Consider your supply selection with the type of diving that you will be doing. For instance, an injectable glucagon kit may work if you are diving in swim trunks, but may not be the most expeditious if you’re in a drysuit or thick wetsuit. Removing a drysuit/wetsuit can be a cumbersome process as it is, let alone having a buddy try to do it so they can administer an injectable glucagon. Again, build in redundancies such as a nasal glucagon kit. Pair your Diabetes supplies with the type of diving you will be doing.

While diving, in case of emergency, I generally keep a small tube of frosting connected to a double ender like the set-up pictured above. I clip this to a D-Ring. My buddy also carries one as they sometimes like to break free. I also carry some form of noisemaker on me in case I need to get the attention of my buddy, fast.

A modern adaptation of a Biblical quote is that “Data will set you free.” When I dive, I log the entire day. I generally log what I eat through the course of the day, when I eat, when I dive, when I disconnect from my insulin pump, when insulin resumes, my surface interval, and I track my glucose both pre- and post-dive. I try to keep my dive days as consistent as possible, eating similar types of foods, quantities – all to reduce as many variables as possible. This allows me to have a consistent and predictable glucose through the course of the day.

Lastly, it’s important to understand yourself and to continue experimenting. For instance, while diving in a drysuit, I was able to adjust the settings on my CGM receiver to consistently buzz – letting me know my glucose was “on target” for where I wanted it to be. Moreover, I’ve even heard of others diving in drysuits with their insulin pumps on. If you are uncertain how your body will react while scuba diving, perhaps take some time to go for a supervised swim. Trying to understand how your body reacts is key. We pursue perfect dive days and with some preparation, even a Diabetic can have them!

Conclusion:

Scuba diving is entirely possible for many people living with diabetes, if they plan diligently, know their bodies, and work closely with healthcare professionals who understand both diabetes and the challenges of diving. With careful monitoring, appropriate preparation, and open communication with dive partners, divers with diabetes can safely enjoy the wonders beneath the waves. Glucose management remains the cornerstone of safety—knowing what to do, when to act, and how to prevent complications is key to a fulfilling underwater adventure.

Cheers to your health and happy, safe diving!

Nancy Huntington-Grahn BS, RN-BC / SDI Instructor Trainer #18847

Cody Hartman, Esq. Rescue Diver.

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