Pop Quiz for Surfers


Not this surfer and not by Mr. Hand.

Definable and reproducible patterns on CGM blood sugar trend plots are meant to be interpreted and used by a Sugar Surfer for immediate self-care decision making. Looking at these plots often and searching for common patterns is part of the practice of Sugar Surfing. Once competent with this skill, the Surfer begin to apply his/her knowledge of what has recently happened (food, stress, insulin doses both basal in nature as well as for meals and corrections) and combines these data with what is happening (or about to happen soon) ‘in the moment”: e.g., a long car drive, a soccer match, birthday party, banquet, or just a quiet afternoon reading a book at home. This is what Sugar Surfing is about: managing in the moment.

To some, especially those not familiar with the use of continuous glucose monitoring, breaking from the dogma of strictly managing to historically identified trends and adherence to strict regimens can be quite alarming. Looking at old blood sugar information and your self-care actions (or omissions) from days or weeks past (i.e., logbook) IS helpful, but only in the sense of giving you the best idea of what might happen next under similar circumstances. You need a rough idea of what to expect and be prepared for the unexpected. Remember: chaos still reigns in diabetes. It has and always will. The best defense is good preparation coupled with frequent action. As Louis Pasteur famously said, “Chance favors the prepared mind”.

Look at the first image. The only annotations are the two blood sugar levels and a dose of insulin. You can estimate the time for each by looking at the timeline across the bottom. This image is meant to challenge you to look beyond the numbers. It’s the PATTERNS that matter. Pattern recognition is a Sugar Surfing skill that must be appreciated and practiced with every glance of the screen. It’s not hard to do nor does it take much time. It just takes patience, consistency and resilience; the three virtues of Sugar Surfing.

Looking at the arrows and the actual number are not as helpful as the trend line itself. It's the trend that shows you direction, duration and rate of change. Only YOU, the Surfer, possess the knowledge of what drives the trend line. Artificial general purpose arrows are not to be trusted beyond what the practiced Surfer can infer from his/her own raw data and life experience.

The answers are displayed on the second image below.

From left to right:

  1. a brief straight line trend (aka “shelf”), followed by;

  2. a 2 hour upward drift (aka “delta wave”), followed by;

  3. another shelf;

  4. then another delta wave;

  5. At this point the high blood sugar level is noticed (it was occurring during sleep).

  6. A dose of 7 units of rapid acting insulin was given.

  7. Next, you see a short period of continued rising BG denoted by the green L (aka “lag”) before the blood sugar trend inflects downward (aka “pivots”) and over the next 2.5 hours a fall in the BG trend occurs (aka “drop”).

  8. As the 7 units of insulin wear off, the fall in BG slows then stops and another shelf emerges.

  9. At this episodes conclusion, the trend line is at a more desirable BG range (at least for this Surfer).