Experiment Pre-Registration: Measuring the Effect of Sleep on the Blood Glucose Impact of Meals (Replication of Ilmo Stromberg’s Results)

Ilmo Stromberg just posted a fantastic write-up of 100 days of monitoring his blood glucose using a CGM. He had tons of interesting observations, but the three that stood out for me were:

  1. No correlation (R2=0.03) between average glucose and sleep score (Oura ring, R2=0.003)
  2. Slight correlation (R2=0.09) between last glucose value before sleep and deep sleep (Oura ring)
  3. Strong correlations (R2=0.36, 0.92, & 0.98) between total sleep the previous night and “meal scores” (a measure of the blood glucose impact calculated by the Veri app from the CGM data).

From my own data, I also haven’t seen a correlation between average glucose and time asleep, but I never thought to check impact on just meals to reduce noise in the measurement.

For the correlations with specific meals, Ilmo had a relatively small data set (3 meals, 4 datapoints each), but the effect was consistent and strong.

I’m interested to see whether I can detect the same effect. I eat a very consistent breakfast and relatively consistent lunch, so I should be able to get a statistically robust measurement in a relatively short time.

I’m pre-registering the experiment here for data quality & transparency and to get feedback on the experimental design.

Details

Experiment

  • Breakfast:
    • I will take 4.5u of Novolog (fast acting insulin, duration of 2-4h), wait 30 min., then eat 50g ketochow with 2 tbsp. of butter (websiteBG testing).
    • This is my standard breakfast and insulin dosage and will be used every day.
  • Lunch:
    • I will take 3u of Novolog (fast acting insulin, duration of 2-4h), wait 15 min., then eat 50g ketochow with 2 tbsp. of butter (websiteBG testing).
    • This is my standard lunch and insulin dosage when I’m not doing a food effect experiment. On days when I am doing a food effect experiment or otherwise need to deviate from this meal, I won’t record data.

Measurements

  • Blood glucose will be monitored using a Dexcom G6.
  • Sleep will be measured using the Oura Ring 3
  • For each meal, I will record:
    • Time of insulin injection
    • Amount of insulin injected
    • Time of meal
    • Any additional observations

Analysis

  • I will conduct an analysis after collecting 30 days of data. If the results are inconclusive, I will collect an additional 30 days of data and re-analyze.
  • Peak change in blood glucose and area under the curve will be calculated for the 2h after each meal.
  • Pearson R (with 95% CI) and p-value will be calculated for the following correlations:
    • Peak change in blood glucose vs. time asleep (breakfast & lunch)
    • iAuC vs. time asleep (breakfast & lunch)
    • Average daily glucose vs. time asleep (prev. night)
    • Average daily glucose vs. sleep score (prev. night)

Please let me know if you have any comments or suggestions on the experimental design.

I will start recording data immediately and will report out the results on March 12th


– QD

3 thoughts on “Experiment Pre-Registration: Measuring the Effect of Sleep on the Blood Glucose Impact of Meals (Replication of Ilmo Stromberg’s Results)

  1. Looks very good!

    Only note to myself that I actually believe there’s more noise on sleep score than time asleep. I should have looked at the correlation between average glucose and time asleep and I will do that in the future.

    1. Thanks! It’s on my todo list to look at the correlations between my Oura ring and manually recorded sleep and other data. Very curious to see if the sleep score gives any benefit over just straight time asleep.

Leave a Reply

Your email address will not be published. Required fields are marked *