I’m curious what actually happens during the 2 hour sensor warm-up. Why is this really necessary? It shouldn’t take that long for the filament to reach body temperature, if I am to take “warm-up” literally. I confess, I have cheated by starting the warm-up delay before I’ve changed my sensor (like while I’m gathering materials). Granted, it’s only a few minutes I save, but it doesn’t seem to make a difference in terms of accuracy. It feels like a deterrent from getting extra time out of a sensor. (“If I need to take a 2 hour penalty, I might as well change it.”)
I use xDrip+ and can tell you that the transmitter (and receiver) actually do have raw data during the “warmup” period, but it doesn’t report “Valid” readings until the 2-hr period and calibrations have passed. I think they want the tissue around the sensor to start to form a healing wound, which somehow makes the readings more reliable…
I have a Vibe and a receiver, and I have sessions on each that are overlapping, so I rarely have a complete “blackout” period – though, after a new sensor is inserted, the receiver that is NOT told to start the session usually goes to ??? for about an hour.
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With the old Medtronic Sof Sensors (aka elephant harpoons), the warm up period was supposedly to allow the sensor wire to hydrate properly. Maybe its the same with the Dexcom.
I always thought the “warmup” was to equilibrate the body’s response to the initial trauma of insertion, temp, ect. Some people do “hot swapping”, where they insert the sensor before removing the old one–then just transfer the transmitter.
It’s a good question. I’m sure I’m not alone in leaving sensors in for longer than the one week that Dexcom recommends. When it’s time to “change” the sensor I just end the session and start a “new” sensor, even though it’s the same one. It’s annoying that it still has to go through the 2-hour warm up session and there is no way to skip it.
I agree - of course the manufacturer isn’t going to help make it easier to use sensors longer than recommended (and avoid buying another one…). As I mentioned above, I use a Dexcom G4/Share and with that have overlapping receivers, plus xDrip+ which gives me reasonably accurate readings (though only on the graph, not as if they’re ‘official’ readings) during the warmup period. See below - the soft white dotted line is during the warmup period. I did NOT tell xDrip+ that I’d restarted the sensor.
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I dunno. With xDrip+ I start the new sensor on my phone but the watch, which I use as the receiver (collector) keeps reading without missing a beat. The first two readings are always wildly high (300+) but then it gets pretty accurate readings after those first two.
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So far, I need a G5 for that – I don’t think the AW watch collector works for the G4 with Share (yet?)…
When you insert a sensor a couple of things are happening,
1 - You are fighting the bodies foreign body response
2 - You are allowing the sensor to hydrate and the polymer screening layers to set up an equilibrium with the surrounding tissue.
While both of these items are pretty quickly established, my guess is that Dexcom has some data which shows that in people with a large foreign body response, equilibrium is reached after X time. Then they probably added 30 minutes or so to that to make sure that the readings were as steady state as possible. Thus avoiding lots of unnecessary phone calls to tech services.
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G5 only. The transmitter has to use a BLE readable by xDrip+ in order to have the watch read the signal. BTW, my opinion is that you’re much better off with the G4 setup. There are sooo many things the G5 broke, plus transmitter life decrease. Don’t get me started 
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The G4/Share receiver can talk to xDrip+ via BLE, but it, so far, at least, they haven’t implemented talking directly to AW for it – was told it’s probably possible, but not a priority.
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I think that the FDA has limitations on Dexcom on how long the sensor can be used. Just like where on your body they can tell you to use it.