Don't forget to set your pump clock back an hour

An FUD public service reminder:

Don’t forget to set your pump clock back an hour.

The end of Daylight Saving Time - a week of waking up an hour early because babies and pets can’t tell time…


Or 3 hours early, apparently, if you’re my child. :tired_face:

So, I’m just curious, as I obviously don’t have a pump so this doesn’t affect me - how do DST changes affect pump settings like a TB for dawn phenomenon? If, say, you have it set for 5 am to head off the rise, but then DST ending means 5 is now 4, are you going to just end up rising a bit before it kicks in at 5, or do you have to switch it to start at 4 and gradually adjust as your body adjusts to the change? (If that even makes sense - not sure I’m really coherent when waking at 4:30am).

1 Like

I don’t think you would have to do it gradually. It may take your body a few days to synch-up completely, but in general people do not have crazy differences in their basal needs from one hour to the next.

If you are at 0.50 units until 4am, you wouldn’t suddenly jump to 1.5 units right at the top of the hour. People have more gradual rises and drops in their basal needs, so the hour change would not cause a drastic difference in basal needs.

The rates on my pump ramp up gradually from 12am to 4am and then go down gradually from there. Little steps in 30 minute increments.

1 Like

Interesting, DST ended here a week ago.


I just change my pump settings and, if it’s only an hour difference, I don’t notice much.

However, I recently travelled across the country where there was a four-hour time difference. I didn’t notice any issues when I went there (four hours ahead), both in terms of blood sugar or my sleep schedule. I just seemed to automatically adjust. But coming back my blood sugar was chaos for a week, as was my sleep schedule.

I have heard of people doing this, but I don’t. I have a jump from 1.4 units to 2.3 units to cover the dawn phenomenon, then back to 1.7 units for the afternoon… My basal rates do need some fine-tuning, but I’ve never done the 30-minute incremental change thing. I think I would probably do it if I didn’t have to adjust my basal rates twice a month for hormones, but having a bunch of incremental basal rates to change would be way too much work and way too error-prone for my liking.


Yes, it is extra effort to setup. But I have it dialed in pretty well, so I don’t have to mess with it too much. I might bump a few hours up or down a little bit on occasion, but I don’t make anymore big changes.

But for people changing them a lot, it would definitely be more work.

1 Like

I wondered about time changes while traveling, too! Whew.

Our physician team has a protocol when changing more than 6 time zones. But for just across they US, they don’t recommend any specific changes.

1 Like

Just discovered that when I changed the time on my Dexcom Saturday night, somehow the year got switched to 2016. So now I have a five-day blank in my Clarity record. The data is there, but for November 2016, five months before I started using a CGM. At least I didn’t wait a month before uploading. Minor nuisance, and lesson learned.


Much better than if you accidentally changed it to 2018.
That would have been a problem.


3 posts were split to a new topic: Crossing time zones

If you load your cgm data to dexcom studio, it allows a choice to display in internal time vs user time. So you could see the real time data, basically in GMT/UTC time.

Current Dexcom Receivers are no longer compatible with the Dexcom Studio application. It has been over 3 years since I was able to download the receiver into the Dexcom Studio.

We now upload into both Dexcom Clarity (automatically via Dexcom G5 Mobile App) and Diasend (manually from Dexcom Receiver via USB).

I downloaded my receiver recently, but receiver may be over a year old. Bummer if newer ones won’t work.i