Scuba Diving with dexcom G5

Could anyone please share the experience of scuba diving wearing the Dexcom ? Did anyone try it already ? Is it possible ? How long does the receiver support and how deep ? For how long ? Thank you for sharing !!!

Disclaimer : I have no experience with this but would think that it would be difficult. I could be completely off base but first you’d have to waterproof the receiver with a case or some sort of waterproof pouch/container. I don’t believe the Dex transmits very well underwater.

Hi Mike Thank you. Actually I’m worried if the part that stays connected to the body and is waterproof will survive the pressure and the depth . It will definitely not transmit any data because of the density of the water. Just wondering if anyone have tried. But thank you!

Hi Martina-

funny you should ask, I was just researching this a few days ago, as I was trying to figure out if there was a way to get my T1D son certified.

What I found:

  • the G4 and G5 transmitter/sensor pairs appear to be waterproof to 8ft (although I am finding slightly contradictory info)
  • the last guy in this thread appears to have destroyed his Dexcom transmitter afer a few shallow surface dives (not even scuba), but was able to remove a transmitter pre-scuba-dive, then reattach it to the sensor post-dive and get it to work (so the sensor had not been damaged by the dive).
  • there are many threads around asking about putting a G4 or G5 in a pressure vessel, but I have not found any that recorded a MO. I may not have searched enough though.

As a caveat, the symptoms of nitrogen narcosis are very close to that of a sugar low.

I got certified and they never questioned me about it. Certain resort dive boats won’t take diabetics because they are worried about liability, so I have never volunteered the info to them. But the person training your son should definitely be made aware of it. About 98% of the training will be in a pool. It’s very safe, you just have to be cautious when you get to the openwater checkout dive.

I have not personally worn my Dexcom on a dive, but I can do that next time and report back. I think the safest thing would be to plan your sensor change to happen when you are finished with a dive. Other than getting extra days out of your sensor, there isn’t much value to having it on when you are underwater.

Michel, as you may know, there is a lot of muscle work involved in diving, and it can drop you quickly. Better to be high for a bit when you are underwater. For me personally, it’s about the only time I can think of where I intentionally plan to have somewhat elevated BG. The risk factor is that you can’t do a thing about a low when you are underwater. If you are down deep and get low BG, you have to surface. There just is no alternative. :frowning:

All the scary worry stuff aside, I say, “Do it!”. I got certified about 30 years ago.

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Hi WestOfPecos,

the question was for my son, I’m a Scuba dive Instructor and tomorrow is “take your kids to work day” so I though I may as well put him in the pool since he’s a certified "Padi bubblemaker "already . But since he got the dexcom for the first time last week, I didnt know what to do. Thank you for your post, I’ll read the link and see if I also find more information on that, I’ll let you know.
Greetings from Miami

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Eric, if you wear the transmitter my guess is you are going to ruin it - even 2 bars might be too much for this little plastic bubble:-). Better take it off before you dive, then try to put it back on afterwards (hopefully an old sensor).

DAN published a really nice set of guidelines, not sure if you saw it.

I was wondering about that: in my last dive I was able to eat hard candy before it had time to melt:-) I think if you took some gel it might work - or something that is hard enough that it won’t melt between the time you take it out of a waterproof wrap and your mouth. I am not saying it’s a good idea - just that it might work:-)

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Martina, I’d love to know what you figure out!

FYI, my son (12 yrs old) is on a swim team and swims 5-15 hours per week with a Dexcom. Diving starts are no problem.

My only desire to do this would be for experimentation and sharing the information as a public service. Ideally, I would have a transmitter that was about to expire, so I would not be out too much if it died. If it was just for my own purposes, I wouldn’t wear it on a dive. But I am always curious on how to break things! :slight_smile:

That strikes me as potentially dangerous. Since you are inhaling through your mouth, having a piece of hard candy in there seems like a choking hazard. And what makes it worse, is if your airway got blocked and you tried to surface, you could have pulmonary barotrauma.

You know I am a gambler, but I would never put hard candy in my mouth when breathing through a reg!

You know that funny piece of plastic that one has to remove in order to insert the Dexcom sensor? It is actually a tool to remove the transmitter if needed in between sensor changes. I have used mine several times to get the transmitter off. It is an ingenious bit of plastic.

@Martina4 , since you are a pro, what do you think? Is there a safe way to take carbs in the middle of a dive?

If I remember correctly, DAN guidelines advise going up to the surface before ingesting any. But I know some divers recommend bringing glucose gels along during the dive. Would you feel comfortable with something like that?

You can get PADI certified with T1D - you will need a certification from your doctor. In my case this was a two sentence letter from my GP stating that my control was good enough to allow me to dive safely. As a PADI certified diver he will be restricted to depths of 40 metres and normal air mixtures only (no nitrox). There are even hand signals for “my BG is Low”. You can buy small waterproof dive containers that clip to your BCD to hold your emergency glucose tabs (you will need one for the buddy too)

The British Sub Aqua Club has a lot of online information on diving. When I started to dive which was around 15 years ago, there was little information from PADI, but I suspect this may have changed.

You cannot dive with a pump - he will have to go untethered and take at least a small amount of long acting insulin. The potential for long disconnect times makes it unsafe to rely on pump basal.

I have snorkelled with a Dexcom (and pump disconnected). The transmitter and sensor were fine but I never went below 4 metres depth - even as a “learner” he will be diving to 20 metres accompanied by a dive instructor. However, I would give it a go. At 20 metres you are at a pressure of 2 bar. The transmitter doesn’t have any obvious holes so it might do OK.

Don’t worry about nitrogen narcosis

The link above will give you some tips. There’s a whole established procedure for checking BG before diving but with a Dexcom it should be easier.


Edit: Missed the post above about removing the transmitter. That might work well.


One other thought. The excitement of diving will possibly cause the adrenaline to give him a good spike. Be prepared to treat the high BG when he gets back up on the boat! Once he gets more familiar with it, that response will settle down.

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Hi WestOfPecos , I have a friend . He has diabetes for over 30 years now and is a technical diver . I always watch out for him . But he does take gel and eats underwater when he starts feeling low. Me as an instructor would never suggest that even tough I agree is better then hard candy. And is also always good to be prepared , you never know how fast your sugar can drop

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Joel, great info in your post and in your link too!

While I have not SCUBA-dived since starting with my Dexcom, I did dive quite a bit prior. I always carried a 15g glucose gel tube with me in my BCD. While I never had to use it specifically for a hypo event, I did “waste” one to see if I could consume one quickly while underwater. It took two intakes and a bit of nasty salt water included, but I determined that I could “safely” take in 15 g of carbs while diving. The test really relieved a concern I had with SCUBA and I never looked back.

W/r/t the Dex, I would just remove the transmitter before the dive and give both the transmitter and the attachment area a good fresh water rinse, then alcohol wipe (to displace the water) before reattaching after the transmitter.

FWIW, my dive target was to start @ 100-170 mg/dl (and NOT trending down) and rarely finished a dive above 200 mg/dl; easily corrected when I reattached to the pump.

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@YogaO , that is great news! You are an experimenter like @Eric2 and myself:-)

I was thinking the same MO. My only question was - will the sensor survive the dive? I don’t see why not, and the guy on the earlier quoted thread has done it successfully.

I am assuming you started the dive with little or no IOB?

No IOB!! No IOB!!
Please, no IOB!!!

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Almost always. I think I had maybe a couple dives where I was over 200 and trending up, so I took half the correction dose.

I only had one dive (in Bonaire) where I was worried about being low, but it was actually after the dive. I had a long swim after surfacing to get back to my dinghy against the wind. When I finally got on board and tested, I was @ 73 mg/dl and I could feel the low coming on. I had glucose tablets in the dink, so I downed 5 (20g) to get me back up.

I can’t imagine a sensor not surviving the dive unless it’s older, starting to lose the adhesive, and gets pulled out when taking off the wetsuit.

Wondering if anyone on this thread did try to reinsert the transmitter after diving and if it worked? Heading on a dive trip in two weeks and wondering how to handle it. I don’t want to ditch my son’s Dexcom the whole week bc it would us some valuable info about trends in this situation (we are one year in). Dexcom said to start a new sensor after diving, but at $75 each, I am not going to do that two or three times. Also, I have read the PADI guidelines and the report from the meeting that generated them. Any advice for bolusing meals beforehand? My son is on MDI. We will reduce basal the night before. Thinking I may do half the breakfast bolus? He is pretty resistant to insulin in the morning.