Circadian optimization using a continuous glucose monitor

I often work with members in my Circadian Retraining Program to help optimize their circadian rhythms.  This is very common with people start tinkering with circadian rhythms, but also necessary when people’s circumstances change.  This is particularly useful when a woman goes through menopause.

Many things change on a physiological level from pre- to peri- to postmenopause.  When hormones change, tweaking things helpw manage symptoms as they pop up.  I suppose some people can get away with winging it, but it’s always useful to have some data to guide the decision-making progress.

That’s why I was thrilled when a member with perimenopausal symptoms asked if a continuous glucose monitor(CGM) would help.  Circadian rhythms not only control blood glucose, but behaviors that disrupt blood glucose levels cause circadian disruption.  When she showed me her results, we immediately had something to work with that also opened a few more things we may need to address later.

Using a continuous glucose monitor to optimize circadian rhythms

Based on the data, there are “optimal” times to do the things that help set your circadian rhythms.  However, optimal to me and optimal to you may be completely different.  Furthermore, optimal for the individual may not necessarily fall in the middle of the bell curve of a clinical study.

For example, some people do best with blocking blue light 90 minutes before bed, others 2 hours.  Some people can have their eating window go from 7am-5pm, others do much better 9am-7pm, and some may need a shorter or longer feeding window.  Some people do better with morning exercise whereas some people do better by pushing it to the late afternoon.

People always ask me what is the best time to eat, or exercise, or block blue light.  But the truth of the matter is it depends.  No matter how you cut it, the only way to figure out what’s best for you is to tweak and then measure how you respond.  I personally like looking at things like heart rate variability or an activity tracker that also tracks heart rate.  But a continuous glucose monitor is another one that’s high up on the list.

Using CGM data

When this client showed me her results, something stuck out like a sore thumb.  Let’s see if you can see it:

Circadian CGM1

You can probably tell the outlier on the chart without me telling you the exact problem.  For the most part, the daytime is pretty ho-hum, with no major issues.  But once we get to around 20:00, blood glucose begins to elevate until it reaches it’s max of 12.9 mmol/L(232 mg/dL) and then drops back in to range but continues to drop below the range(Not shown, but similar to the low readings from 00:00-04:00 earlier in the day).  That’s way too big of a glucose spike at night.

Now, if we would have simply done spot checks of blood glucose throughout most of the day, we wouldn’t have noticed anything.  Blood glucose seems to stay well in range while she was awake, save for the bump right before bed.  Any sort of blood glucose elevation that high in the later evening will disrupt circadian rhythms and normally disrupt sleep if it happens all the time.

Using other circadian data

If we look at this data in isolation, that drop in the early morning hours appears like a poor cortisol awakening response.  Fortunately, we have recent data on that:

Circadian salivary cortisol

Morning cortisol is more than adequate, which leads me to believe that we’re dealing more with an insulin/blood glucose regulation issue not due to cortisol.  This gives us some targets to hit:

  1. Improper timing of blue light blocking-Melatonin inhibits insulin release and re-establishes insulin sensitivity the next day.
  2. An inability to maintain melatonin output throughout the night
  3. Reduce carbs at night or shift dinner earlier
  4. Redistribute calories earlier in the day

While the salivary cortisol pattern isn’t ideal, I don’t think it’s the immediate variable that needs to be addressed. That cortisol bump midday could actually be a result of the factors mentioned above.  So, we changed blue light blocking, redistributed carbs and calories to other parts of the day, and moved some nutrients that may help with the melatonin output to dinner.  As a result, a much better glucose response to dinner and better sleep:

Circadian cgm2

As you can see, a much flatter response to dinner with a peak at 9.3 mmol/L(167 mg/dL) that happened much earlier.  The result, a much better nights sleep and better glucose levels during the morning the next day.  We may tweak that a touch, but we’ll give it time to see if what we did makes it fall in line.

Moving forward

We still have a few tweaks to make as perimenopause opens up constant challenges, but check one off the list.  Ironically, these issues came out of nowhere.  This woman was humming along quite nicely when things just changed on a dime.  I wouldn’t be the least bit surprised if we aren’t thrown another curveball down the road.

Fortunately, we have a nice piece of data to work with to measure the effect of our little tweaks.  Too many wing it and just go by how they feel, and this is a mistake.  Data always trumps no data.

If you want to dig a little deeper in to the relationship between melatonin, blood glucose regulation, and metabolism, there’s a wonderful review article just published.  You can check it out, just click here.

Need help working on your circadian rhythms? We now have a shop for our programs with different programs and bundles to fit your needs. We also have some solo video for sale as well. Check that out under “Shop Program” at the top of the page.

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