T2DM after 38 days on Humalog night hypos

Diagnosed 28 years ago and have progressed from diet and exercise, to Metformin, to Lantus and now Humalog. I received a Dexcom G6 2 days ago.

From what I’ve read the basal/bolus ratio for type 1 DMs is close to 50/50. However I think my beta cells are not completely kaput. I am currently taking 30U of Lantus, 2/3 at bedtime and 1/3 12 hours later. I have been dosing the Humalog at 1U/23grams carb. This has been working very well.

Yesterday I did a 45 minute moderate to hard Zwift stationary bike ride an hour and a half before dinner. My BG dropped during the ride from 140 to 103mg/dl. It was holding at 103 until dinner. It is possible I over estimated the carb grams dosing 2.5U. BG rose to 143 2 hours postprandial and was at 95 at bedtime when I injected 20U of Lantus.

2 hours later the G6 woke me with BG at 64mg/dl. I ate a couple of peanut butter crackers, 2 hours later back to 64 got up ate 30g of carbs. BG rose steady to 160 and then back to 150 prior to breakfast.

My real problem is I don’t have a diabetic specialist available in my area. For some reason we have all kinds of doctors but not one endo. Let’s see if this screenshot shows up.

1 Like

After an intense or simply long exercise session you will be more insulin sensitive than if you had exercised for a shorter or less arduous time, and the effects can last for up to 24 hours. Next time you exercise for a long time I would plan on cutting back or maybe even eliminating the Humalog and correct later if you need to.

1 Like

I’m definitely on a learning curve.

Oh, BTW I don’t have any local endo’s either but my local clinic where I get my primary care facilitates telemed endo appointments. Have you asked your PC if they can set something up for you?

1 Like

That’s a good idea. I’ll bring that up with her.

@Luis3 , There are several items flying in the wind here.

[1] what has your exercise activity been prior to your Zwift biking yesterday?

[2] the dip in your CGM data at 3am on 28 Feb 21 could be a COMPRESSION LOW. Also, the drop at 12:30 AM on 1 Mar 21. I will attach info about a compression low.

[3] The rise in CGM data on 28 Feb 21 could be ‘dawn effect’

[4] Generally speaking, what part of the world are you in?

Here is the Compression Low info

Compression Low

BACKGROUND: Compression lows are caused by the person’s body pressing against the mattress, pinning the CGM sensor/transmitter (CGM) between the person’s body and the mattress during sleep. First, the interstitial fluid (IF) is the fluid around body cells. Most of the time IF is exchanged with fluids in the blood vessels. During this exchange, IF glucose is enriched and cellular waste products are removed from the IF all over the body.

THE PROBLEM: When a person is in sound sleep and is mashing the CGM into the mattress, the IF is also mashed. It is this mashing or compressing of the IF that causes the IF not to exchange as it normally does. Since the cells around the CGM sensor wire continue to consume (eat) the glucose available in the compressed area around the sensor wire the glucose in the area drops.

OBSERVATION: It is this low reading in the CGM data that is usually seen as a nearly level data graph and then a sudden drop of the glucose level. Because it is a low brought about by the pressure on the CGM, the term COMPRESSION LOW has been offered in pumping circles. Because the Compression Low is a low glucose only in the area of the CGM, a finger stick performed in response to a LOW alarm will show NORMAL. The variation between the finger stick and the CGM data leads to frustration and bewilderment, believing technology is the source of the error.

The next observation is the blood sugar measured by the CGM will return to a value near where the CGM line was before the drop in CGM value. The near level line, the drop & alarm, the finger stick of different reading, and the return to the near pre-alarm value is the full picture of the COMPRESSION LOW.

Here is a link to Susceptibility of Interstitial Continuous Glucose Monitor Performance to Sleeping Position

HYPERLINK “Susceptibility of Interstitial Continuous Glucose Monitor Performance to Sleeping PositionSusceptibility of Interstitial Continuous Glucose Monitor Performance to Sleeping Position

1 Like

@Jay6 You are speaking my language. That is very interesting about the compression low. I suspect this would be on reason for me to never use the upper arm as a sensor location. I tend to sleep on one arm or the other throughout the night.

  1. I am fairly active, but had not done a bike ride is a couple of weeks. I would call this ride moderate with some sprints. It was mostly in HR Zone 3 with some zone 4 and less than a minute in zone 5, if that means anything.
  2. Compression low - CGM makers should put that in their user guides.
  3. I am familiar with Dawn Phenomenom and has since learned here of Feet on the Floor. Looking at last night’s data DP started at 2A and peaked at 3:30A. FOTF rising at 5:45A peaking at 6:45A.
  4. I live in south central Texas, USA. I did find an endo in my area other than Doctor Concierge. When I next speak with my PCP I will asks her if she would do a referral.

Dr. Dean Blevins is Board Certified in Endocrinology, Diabetes, & Metabolism and Board Certified in Internal Medicine.

His clinical interests include Diabetes, specifically Diabetes technology and research; Thyroid disease, including Thyroid cancer, Pituitary and Adrenal disorders; as well as Osteoporosis.

I will pay attention to if it is possible that I am compressing the sensor area in the future. That said last night without any exercise was really odd. I took 20U Lantus w/BG at 123. BG went steadily down to 10:40 when I got an alarm for 63. Ate 21 grams carbs and BG was fairly flat at 73 for two hours. Then a steady 90 to 100 for 1 hour, ramping up to 140s going back down to wake up with 123.


Compression Lows cannot be documented with the statistical requirements for inclusion in documentation. Anecdotal data is all that exists.

I am concerned about your arm use, since you are in the USA, here is what I have found about some CGM issues. Discuss with your new doctor & possibly get letters of variance.

As far as the CGM sites are concerned in the USA, using a site outside those approved by the FDA following Dexcom research and development place you in peril of footing the bill if you lose a wire. Sure, G6 is approved in other countries for other locations beyond the abdomen. Here in the USA, you are limited to the belly.

Here’s why. From what I have seen watching the way FDA does approvals, we are still in the post-thalidomide tragedy mentality of the early 1960’s. The US Congress and American people supported a “never again” mentality will anything be approved unless it is safe. The cases of phocomelia were horrible. Some say this is a strong language, however, it is still used today in language related to FDA rationale, power, and need for authority.

Here in the states, everything must be checked and double checked and scientifically proven to be safe. Who knows, until proven otherwise, the placement of CGM sensor wires in the upper arm may provoke the growth of new hands in the upper harms (NOT).

As I understand the regulatory process, if a prescriber wants to use something in a manner different than approved by the FDA (called off label), the prescriber must write to the manufacturer, describe the situation, and request off label approval. Many people are told by their prescribing doctors, “Oh, just go ahead and do it.”, not realizing the Pandora’s box which may be opened in a misadventure. I have seen local newspaper coverage in days past of malpractice lawsuits shining the light on such issues.

The purpose of this group is support. Sharing published regulatory & usage information is a form of support. Providing information from contradictory, inapplicable, & unfounded sources without substantiation is not supportive & may in the opinion of others be an undermining of veracity.

In regard to claims about sites, it is the savvy claims clerk in the insurance company that creates the problems related to off-label use.

When a claim comes in for the removal of a wire from, hypothetically, posterior upper arm, and the insurance clerk notifies the hospital or doctor making the claim, additional information is needed. What type of wire? If the response is a Dexcom CGM sensor wire, the clerk checks to see if the device was being used according to published standards.

If the device was not being used according to published standards, the insurance clerk should deny the claim as ‘device not used as prescribed’ (because the prescription is for an FDA regulated device to be used according to FDA authorization). Failure to use according to directions, without variance, constitutes negligent usage, placing the onus, and therefore the bill, on the user.

The point of my post about ‘proper placement’ is not what the patient would tell anyone. It is what the health care bill to the insurance company would reveal and the sequelae.

One additional item to remember is being told by a prescriber it is permissible to use an item outside FDA authorization or ‘off label’ in the case of devices requires the device manufacturer to be notified and acknowledge the variance in writing according to the FDA.

Anyone in this situation should verify and obtain copies of correspondence their physicians have had with Dexcom seeking approval of off label locations and the clinical reason for the requests.
The mountain of off-label requests will be the only impetus medical device manufacturers have to re-open the approval process and divert resources to current product situations. In the meantime, inspection of medical device companies’ prospectus (yes, the plural of prospectus is prospectus - see Oxford Dictionary) will show major investment in R&D (new product research & development [FDA required testing, etc])

BOTTOM LINE: As informed users of ‘restricted medical devices’ (restricted medical device includes but is not limited to a device & accessories requiring a physician’s prescription), we the users must learn the “Thalidomide era” safeguards and apply those same rules to have common sense brought to the forefront. Here is the link from the Dexcom website (make sure you are on the USA page):
Where can I insert my Dexcom? [link is for USA – country selection is in upper right of screen]

This is the same as INSULIN PUMPs on airplanes. I have yet to find in FAA regulations the full approval process demonstrating insulin pumps are safe to use on commercial aircraft and that the radio waves generated, or electromagnetic interference (EMI) will not cause the plane to crash. Twenty year ago, when CGMs were first making their appearance, there was rattle about the radio waves from the CGM transmitter being in the same frequency range as some important avionics. Use of items operating in those frequencies were unproven and deemed (by FAA regulation) dangerous until proven safe. (one of the reasons given 20+ years ago when I started pumping).

This is a long post. The picture is big. Let’s pull together and get the eyes opened so location in one country is good in another.

Hope this provides the sunshine needed. The comment is to illuminate the situation.

1 Like

Thanks for a great read, Jay. Just to be clear I am using the sensors on the prescribed place on the abdomen, but I know from browsing the web that some users use the arms.

1 Like