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You cannot wear a Dexcom G7 continuous glucose monitor inside a hyperbaric chamber during treatment. Remove it before every session. The pressurized environment can damage the sensor, produce inaccurate readings, and cause device malfunction. Dexcom’s guidelines confirm the G7 has not been tested or approved for hyperbaric conditions, and most treatment centers require patients to remove all electronic medical devices before entering the chamber.14
This creates a real challenge for diabetic patients undergoing hyperbaric oxygen therapy (HBOT), since blood glucose management during 60 to 90 minute sessions matters. Several reliable workarounds keep you safe without compromising either your glucose monitoring or your treatment.
What does Dexcom officially say about hyperbaric use?
Dexcom’s product labeling explicitly addresses environmental limits for the G7. The user guide states the device has not been tested in hyperbaric conditions and should not be used where pressure exceeds normal atmospheric levels.1
This applies not only to medical hyperbaric chambers but to any pressurized environment, including:1
- Medical-grade hyperbaric oxygen therapy chambers (1.5 to 3.0 ATA)
- Mild hyperbaric chambers used at home (1.3 ATA)
- Commercial diving chambers
The same restrictions apply to other Dexcom models and competing CGM systems from Abbott (FreeStyle Libre 2, Libre 3) and Medtronic (Guardian 4). No CGM system currently on the market is validated for hyperbaric use.23
The Dexcom G6: the only CGM with published hyperbaric data
The G6 transmitter is the only CGM with published hyperbaric safety data. A 2020 study by Bliss and colleagues (Undersea and Hyperbaric Medicine) tested G6 transmitters through 11 pressurization cycles to 45 feet of seawater, finding no functional changes during exposure and no structural damage afterward.2
Important limits apply: testing was done in multiplace chambers only, and a 2024 publication by Katsnelson and colleagues states that CGMs have not been validated for repeated hyperbaric exposure and should not be used in oxygen-pressurized monoplace chambers.3 Because the G7 is a different generation with different internal components, the G6 data does not transfer to the G7.
How do you monitor blood sugar during hyperbaric treatment?
You manage glucose with fingerstick checks before and after each session, since no CGM or meter can go inside the chamber. The key is a routine that covers before, during, and after treatment.5
Before entering the chamber
| Timing | Action | Target Range |
|---|---|---|
| 30 minutes before | Fingerstick blood glucose check | 100-250 mg/dL |
| 15 minutes before | Remove Dexcom G7 sensor | N/A |
| Immediately before entry | Confirm glucose, eat a snack if below 120 mg/dL | 120-200 mg/dL ideal |
Most centers want diabetic patients to enter with glucose between 120 and 200 mg/dL. Starting at the low end of normal (70 to 100 mg/dL) creates hypoglycemia risk during the session, since HBOT can lower blood glucose through increased metabolic activity. That metabolic drop is one of several hyperbaric chamber side effects worth understanding before a course of sessions.
During the session
Inside the chamber, fingerstick testing is not possible, because glucose meters and lancets are not allowed in the pressurized, oxygen-enriched environment. This is why pre-session glucose matters so much. If you feel symptoms of hypoglycemia (sweating, dizziness, confusion, trembling), tell the technician monitoring your session immediately. All accredited centers have emergency protocols, including the ability to stop and decompress safely.4
After exiting the chamber
Check glucose with a fingerstick meter right after you exit. Many patients see a drop of 20 to 40 mg/dL during a standard 60-minute session, so keep a snack available. You can reapply your Dexcom G7 once you are back at normal atmospheric pressure.
How do other CGM systems compare for hyperbaric use?
No CGM is approved for hyperbaric use. Here is how the major systems compare.23
CGM Systems and Hyperbaric Compatibility
| CGM System | Hyperbaric Use | Published Safety Data | Notes |
|---|---|---|---|
| Dexcom G7 | Not approved | None | Remove before session; may need a new sensor start after |
| Dexcom G6 | Not approved | Multiplace only (Bliss et al., 2020) | Same pressure limits apply; G6 data does not transfer to G7 |
| FreeStyle Libre 3 | Not approved | None | Adhesive may fail under pressure changes |
| Medtronic Guardian 4 | Not approved | None | Insulin pump must also be removed |
How do you manage diabetes during a course of HBOT?
Patients on multi-session protocols face ongoing management challenges. Many wound healing protocols run 20 to 40 sessions over several weeks, so sustainable glucose strategies matter.56
Insulin pump considerations
If you use an insulin pump with your Dexcom G7, the pump must also come off before entering the chamber. Pumps contain electronics and batteries not rated for pressurized environments, and delivery rates may be affected by pressure changes. Work with your endocrinologist on a treatment-day protocol. This usually means switching to manual injections on treatment days, adjusting basal rates before disconnecting, timing sessions to minimize disruption, and keeping rapid-acting insulin available for post-session corrections.
Blood glucose patterns during HBOT
Diabetic patients commonly see these glucose patterns during a course of treatment:
- During sessions: glucose tends to fall by 20 to 50 mg/dL as increased oxygen availability supports cellular glucose uptake.
- Immediately after: a brief rise of 20 to 30 mg/dL is common as stress hormones normalize.
- Over the course: some patients report better overall control after 10 or more sessions, possibly tied to reduced inflammation and improved circulation.
Pre-session glucose between 120 and 200 mg/dL is the standard safety target at most accredited centers.5
What should you ask your hyperbaric treatment center?
Before your first session, ask these questions to confirm the facility can safely accommodate diabetic patients:4
- What is your protocol for diabetic patients during HBOT?
- Do you have glucose tablets or juice available in the chamber area?
- Can the technician communicate with me during the session if I have symptoms?
- How quickly can you decompress the chamber in an emergency?
- Do you require specific pre-session glucose ranges?
- Have you treated other patients who use CGM systems like the Dexcom G7?
Reputable centers will have clear answers. If a facility cannot describe its diabetic-patient protocol, consider a center with more experience. UHMS-accredited facilities are required to have these protocols in place.
Should diabetic patients get HBOT?
HBOT has FDA-cleared indications for specific diabetic conditions, and managing your CGM around treatment is a manageable trade-off for real therapeutic benefit. The strongest evidence is for non-healing diabetic foot ulcers: in the HODFU randomized trial (Löndahl et al., 2010), complete ulcer healing at one year was 52 percent with HBOT versus 29 percent with placebo (P=0.03).6
HBOT is indicated if you have:
- Diabetic foot ulcers that have not responded to 30 or more days of standard wound care
- Wagner Grade III or higher diabetic wounds
- Compromised skin grafts or flaps related to diabetic vascular disease
- Diabetic osteomyelitis not responding to antibiotics alone
- Radiation injury to tissue
Talk to your doctor first if:
- Your glucose is frequently above 300 mg/dL or highly unstable
- You have severe hypoglycemia unawareness
- You are considering home hyperbaric therapy without medical supervision
- Your A1C is above 10 percent and glucose management is not yet stable
A Cochrane review (Kranke et al., 2015) found HBOT improves diabetic ulcer healing at six weeks but not at long-term follow-up, and does not reduce major amputation rates, so treat it as an adjunct to good wound care, not a standalone cure.7 For the broader clinical picture, see our guide on the hyperbaric chamber for diabetes.
Can I wear my Dexcom G7 in a hyperbaric chamber?
No. The Dexcom G7 must be removed before entering a hyperbaric chamber. The pressurized environment can damage the sensor, produce inaccurate readings, and cause device malfunction. Dexcom’s labeling states the device has not been tested for hyperbaric conditions. Always check blood glucose with a fingerstick meter before and after treatment.1
Will hyperbaric therapy damage my Dexcom G7 sensor?
Potentially yes. Pressure changes during compression and decompression can crack the sensor housing, displace the subcutaneous filament, and cause adhesive failure. Even if the sensor looks intact after hyperbaric exposure, readings may be unreliable and should not be used for insulin dosing. The only CGM with published hyperbaric testing is the older G6, and that data does not transfer to the G7 (Bliss et al., 2020).2
What should my blood sugar be before entering a hyperbaric chamber?
Most centers recommend blood glucose between 120 and 200 mg/dL before entering. Starting below 100 mg/dL increases hypoglycemia risk, since HBOT can lower glucose by 20 to 50 mg/dL during a session. Confirm the exact protocol with your treatment center, and eat a snack before entry if you are below 120 mg/dL.5
Can I use a FreeStyle Libre instead of Dexcom in a hyperbaric chamber?
No. The FreeStyle Libre (all versions, including Libre 2 and Libre 3) has the same hyperbaric limits as the Dexcom G7. No CGM is currently approved for pressurized environments, and CGMs are not validated for oxygen-pressurized monoplace chambers. Fingerstick meters remain the only reliable option for pre- and post-session monitoring.3
Does hyperbaric therapy help with diabetes?
HBOT has FDA-cleared indications for diabetic wound healing, specifically non-healing diabetic foot ulcers. In the HODFU trial, clinical-grade chambers at 2.0 to 2.4 ATA improved one-year ulcer healing to 52 percent versus 29 percent with placebo (Löndahl et al., 2010). Effects on insulin sensitivity and circulation are proposed mechanisms but are not FDA-cleared indications.6
How many hyperbaric sessions do diabetic patients need?
Typical diabetic wound healing protocols involve 20 to 40 sessions, usually 5 days per week for 4 to 8 weeks, each lasting 60 to 90 minutes at 2.0 to 2.4 ATA. In the HODFU trial, patients completing more than 35 sessions healed at higher rates. Your hyperbaric physician sets the exact number based on wound severity and healing response.6
Sources
- Dexcom, Inc. Dexcom G7 User Guide: Environmental and Safety Information. dexcom.com/en-us/safety-information.
- Bliss C, Huang E, Savaser D. Safety of a continuous glucose monitoring device during hyperbaric exposure. Undersea Hyperb Med. 2020;47(1):13-19. PMID: 32176942.
- Katsnelson G, Salvatori M, Djaiani G, et al. Continuous glucose monitoring in diabetic patients undergoing hyperbaric oxygen therapy. Diving Hyperb Med. 2024. doi:10.28920/dhm54.1175.
- Undersea and Hyperbaric Medical Society, Safety Committee. CGM monitoring in hyperbaric environments (MEDFAQ). uhms.org.
- Hadanny A, Meir O, Bechor Y, Fishlev G, Bergan J, Efrati S. The safety of hyperbaric oxygen treatment: retrospective analysis in 2,334 patients. Undersea Hyperb Med. 2016;43(2):113-122. PMID: 27265988.
- Löndahl M, Katzman P, Nilsson A, Hammarlund C. Hyperbaric oxygen therapy facilitates healing of chronic foot ulcers in patients with diabetes. Diabetes Care. 2010;33(5):998-1003. doi:10.2337/dc09-1754 (PMID 20427683).
- Kranke P, Bennett MH, Martyn-St James M, et al. Hyperbaric oxygen therapy for chronic wounds. Cochrane Database Syst Rev. 2015;(6):CD004123. doi:10.1002/14651858.CD004123.pub4.
Medical Disclaimer
The content on BaricBoost.com is for informational purposes only and is not intended as a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay in seeking it because of something you have read on this website.
Author
Seph Fontane Pennock is the founder of BaricBoost.com and Regenerated.com, a clinic directory for regenerative medicine serving 10,000+ providers across the United States. He previously built and sold PositivePsychology.com, which grew to 19 million users and became the largest evidence-based positive psychology resource on the web. Seph brings direct experience as an HBOT patient, having completed protocols at clinics across three continents while navigating mold illness, systemic inflammation, and autoimmune conditions. His treatment journey includes hyperbaric oxygen therapy, peptide protocols, NAD+ therapy, and consultations with specialists from Dubai to Cape Town to Mexico. This combination of entrepreneurial track record and lived patient experience shapes everything published on BaricBoost.com. Every article is grounded in peer-reviewed research, informed by real clinical encounters, and written for patients making high-stakes treatment decisions. Seph's focus is on bringing transparency, scientific rigor, and practical guidance to the hyperbaric oxygen therapy space.
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