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Dexcom G4: Exercising my Demons.

There aren't any stupid questions. Or so I was told by every teacher in every classroom, growing up.  But I think the Dexcom is the exception to that rule.

Because when it asks me "???" with that blank look on its screen, I can only throw my hands in the air and say, "WHAT? What is your question?!"

With the Seven Plus system, I had my fair share of the Triple Question Marks.  Usually they signaled that a sensor was about to give up, or that something else was en route to borked.  But for the last month on the G4, I hadn't seen the dreaded triples. 

Until last night. 


While I was at the gym, with the Dexcom receiver sitting safely on the treadmill shelf, the receiver showed the "lost signal" icon.  Which, according to sources, means that I'm "out of receiver range," meaning I'm too far from the receiver, meaning I'm not even close to it.  Meaning that I'm totally confused because the transmitter and sensor were less than three feet from the receiver when it claims to have lost the signal.

Meaning that I was extra frustrated when my meter showed a 50 mg/dL before driving home after my workout.  Symptom-free lows plus a questioning Dexcom receiver equals frustration.  (That's pretty much the only kind of math I can do, right there.)

This has happened a few times for me at the gym, while on the treadmill specifically, but the Dexcom usually "finds" me soon enough and my numbers reappear on the graph.  Last night, however, the Dexcom oscillated between the lost signal and triple question marks for my entire workout.   And it didn't sort itself out until about midnight ... five hours after going rogue. 

But all night long?  Totally fine.  And all day, so far?  Also fine.  Is it the treadmill that's making the G4 go berserk?  Does the new system hate running?  (I can't blame it, if that's the case.  I hate running, too.)  Is this sensor a fickle one?  Does this happen to other people while they're at the gym?  Is it the friction of my clothes against the transmitter?  Is it something about the treadmill itself?  What can I do to prevent it? Will Batman escape the machine before being turned into mashed potatoes? 

Or is that just a stupid question?  (???)


When I got the G4 I wore it for less than a week and every night around 8 pm no matter what it went ??? On me and didn't sort itself out for a few hours. I also had three sensors die on me in that short period of time (not sure of that's my fault or something weird with the sensors). I called dexcom and they replaced my wasted sensors but didn't have much of an answer for me otherwise. Perhaps it's just kinks needing to be worked out of the new system? Frustrating none the less.

Kerri - I believe you wear the sensor on your legs, right?

If you're running, it might be the impact on your leg muscles jarring with the sensor wire. With running, there's a lot more pounding on those muscles than, say, an elliptical machine.

To investigate "scientifically," it might be interesting to wear the sensor on your stomach/arm for a week, and see if the same thing occurs while at the gym...?

My Dexcom 7+ hates running. Even in the boob pocket of a sports bra it says out of range and then ??? Believe me, my boobs aren't big enough to be out of range from the sensor on my arm! Everything works fine however fine on an elliptical machine, so yes Dex hates running.

I don't have G4 sensors yet due to insurance/mail company stupidness (here's hoping I get a phone call today!) but I am having ??? frustrations with my 7+, inexplicably, every night, for hours. Frustrating, since overnight lows are the main reason I use Dexy. The last five mornings I've woken up to ??? and a graph thats basically empty, and it's been happening pretty regularly for three sensors now... Is mercury in retrograde or something?

The same thing happens to me, but only when I run. I am training for a half-marathon and on all my long runs, I get the question marks or the hour glass, but as soon as my run is done, back to normal. When I work out at the gym (I don't run at the gym) I never have this problem. I talked to tech support at Dexcom last week, and they were just as confused as I was!

It's because when we had lunch yesterday you totally said that the new Dex keeps up a lot better at the gym and doesn't give you the ???. Seriously, you totally jinxed yourself. Hopefully now that you've blogged about it, the curse is broken and it will be all good from here!!

Me too, only with running, not biking. Dexcom was confused for me as well.

I'm glad you posted about this issue occuring with the new G4. I've worn the G4 now for 2 weeks and I'm getting the "out of range" signal at the strangest times. What happens is I put my winter coat on at the end of my work day (the coat is not crazy thick). I put the receiver in the left hand pocket. By the time I've gotten to my car and put the receiver in my cup holder (just what I do) the thing is saying "out of range"!!! It will then stay out of range for 60-90 minutes and then magically wake up. This ONLY happens in the evening from 5-6:30 p.m. I have worn the coat other times and not had the receiver stop working. Something has to be up with the new system. BTW - this entire time the receiver has never been more than 12 inches away from the sensor (located on my left thigh).

I have been using the G4 for about a month now and I am also see the ??? and out of range symbol. I have been able to recreate this, I would go outside wear a light jacket and sensor would give out of range, I do have installed on the back of my arm and was throwing the ball for my dog and thought that might be someting but it does not happen every time. The signal will come back and seems to be working great other times. I thought it might be the cold about 30F but its happened at other times. This is my first experience with CGM and I really like being able to see what's going on.

The sensor does not seem to tolerate motion well - I get the same thing with running. Also, my rep told me to keep the receiver away from metal as much as i can because metal can disrupt the wireless frequency. Maybe you're experiencing a combo of both those things?

I have been wearing my G4 since the beginning of November and although I have never gotten the ??? message I have had it go out of range several times. Each time the receiver has either been in my pocket or sitting on the table next to me. Sounds like this is a common problem with the new device. Maybe we all need to start calling Dexcom so they can solve this problem.

I believe it was destiny! :) This happened on our son's G4 tonight. We are new to CGMs and the G4. For the last hour, I have been scouring the users guide wondering what in the hell I did or he did. I just saw your post and all the responses. I am sorry this frustration has so many scratching our heads...but for me, it was the right post at the right time. So thank you! (And I am sure my son would thank you because now I won't be quizzing him again in the morning to see if he pressed something he should not have!)

My 10 year-old daughter just got her G4 last Friday and we never saw ??? until right now.
She's in bed sleeping and it changed for no apparent reason. Keeping fingers crossed that it starts tracking her BG soon because other than this, it's been wonderfully on spot!

This (???) has happened to me also while on the treadmill and when I left the dexcom on the treadmill. I think this happens due to some sort of interference from the treadmill, could be magnetic. It doesn't happen all the time and happens rarely if I keep the dexcom in my pockets instead. I have not experienced this behavior while biking or running or jogging or walking. Now I keep the dexcom in my pocket all the time when I'm in the gym and don't ever leave it on the machine/treadmill.

I had this happen the first time I did my daily rowing with my new G4 about a month ago. I called Dexcom and the person on the phone told me it was because of moisture. (I do sweat a lot when I row) It has never happened again. Go figure?

I wear my sensor in the "love handle" area and have not had much of a problem. I received ??? once on the first sensor I used, but I was new to Dexcom and I thought it was just because I was on my 7th day and needed to change the sensor. I am on my 3rd sensor now (and it's lasted 21 days so far!), and I haven't had any other ??? or out of range errors. Perhaps it's because there's no motion? Arms and legs obviously move around a lot, but with the sensor on my side, it more moves with my body?
It does sound like this might be something Dexcom should look into though...

We are all partial to our particular systems, and I wear the Revel pump by MM with their CGM. I had considered switching over to Dexcom at some point, primarily because I thought it would be nice to take frequent pump vacations to keep my infusion sites fresh, and that with the new Dexcom's supposed longer range I'd be able to just have it in my handbag or on my desk, rather than around my waist. However, I guess DexCom still hasn't gotten rid of its ??? problem, which is why I went with MM back in 2008. Are you listening, Dexcom? I hope so! (I never get ??? with Medtronic, and only wacky numbers if there's a bad sensor. I've had only one in the past 12 months.)

This post just makes me feel better about deciding to forgo the Platinum G4 upgrade right now. Dexcom simply has to get this very expensive, time consuming tool right before I'm okay with sinking that much cash into a new device.

I think the legs have a lot of problems handling running. I have had several that seem to have this problem (and I am on the 7 plus). For some reason it looses the signal or has trouble tracking my BG. Generally, after I finish my run things calm down. Considering the legs aren't technically approved for Dex use, I can't really complain, though I wish it was better.

I had the seven+ for about a year and a half. Just got the g4 yesterday and 12 hours later it is throwing the dreaded ???. From reading other peoples posts I did have it sitting on my phone. I wonder if it is truly the metal on metal thing going on. I do, however, like the thiness of it.

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