G7 startup overlap?

  1. Each Dexcom G7 has its own transmitter.

  2. When a G7 sensor expires, you have a 12-hour grace period where it will continue functioning. (Which is really nice.)

  3. When you insert a new G7 sensor (if I read correctly) the sensor session/warmup starts automatically.

All that together, unless I’m mistaken, means you can have two sensors going at the same time. The old sensor expires. You put in a new one. You wait half an hour. That’s when you stop the old sensor and pair the new one, which should have completed its warmup.

Does that work?

I suppose if the new sensor does need to be paired, and you’re using a pump, you can pair the sensor with your phone first, wait for warmup, and then switch over on your pump. You have to pair them separately anyway, since it’s a new transmitter. That would even let you make sure warmup is successful (and compare readings from both sensors) before changing the pump over to the new one.

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Correct with a couple caveats… a) G7 sensor warm up begins when you take the top off the applicator, and b) you don’t need to pair it to make it warm up - only to see the results.

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I don’t pair the new sensor for hours because dexcom, for me, is a little inaccurate the first few hours. I let it sit 4-5 hours then pair the new sensor and stop the old one. When the new one pairs it uploads all the data since warmup so you see 2 lines on the dexcom app.

I find the G7 to be very inaccurate during the first 12+ hours, always with false low readings (when compared to blood tests and how I feel). I had the same exact problem with the Libre system. I’ve been applying a new G7 sensor when the 12 hour grace period starts on the old one (last day of wear). I’ve had luck pairing the NEW sensor to my Dexcom phone app while I DON’T yet pair the new sensor with my G7 receiver and that lets me see both sets of numbers simultaneously. However a couple of times doing this forced my old sensor to switch off. It seems to work if I pair with my phone first. If I pair with the receiver first, the receiver seems to send a message to my phone that the older sensor has been replaced and it stops working, forcing me to pair the new sensor to the receiver. I recommend if you’re going to try this- to NOT pair with any device for several hours, to give the new sensor time to “warm up” before the old one shuts down. Also be aware that Dexcom recommends that you NOT calibrate a new sensor until it’s been worn for 12 hours. Which just proves (to me at least) that the readings are unreliable during the first 12 hours. The G7 is otherwise very good, I just rely on fingerprick testing during the initial 12-24 hours until it “settles in”.

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I had the same problem with the G6. And the Guardian 3 sensors before that. I’m only on my second G7, but so far it’s been warming up smoothly for me. Hopefully that keeps up. (I’d cross my fingers, but I’m Jewish.)

The problem I’ve been having is that with the sensor in my arm instead of my belly, and the transmitter being smaller, the pump is much more liable to lose the signal. I’m gradually learning how and where to keep it, especially at night.

But good to know you can keep both sensors going. I think I’m going to try that when this one expires.


@WearsHats I just activated my new sensor after wearing it for 6+ hours. Here’s the graph you can see there are double lines and zero gap for warmup (which happened before lunch)


I remember the first time my chart showed double the dots from G7 sensor transitions. I thought the app was broken so I called Dexcom support. They had no clue either but were able to see my double readings on their side. As we were trouble shooting it I noticed the dots were on different 5min reading patterns. This lead to tracking when first and second sensor was installed and then mapped them to the different sensors. Took a good hour to figure it out! But that was in Feb 2023 when G7 started shipping.

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I’m still using the G6. But I wear a pump holder arm band at nite on the arm with the sensor. Seems to work well for me