The ancient greek aphorism"Know Thyself" is powerful, but can be an unstoppable force of change when self-knowledge meets action.
A promise beyond Diabetes
Continuous Glucose Monitors (CGMs) were developed to aid in the management of Diabetes Mellitus, most commonly referred to as Diabetes, and covering Type I Diabetes (a condition affecting the production on insulin in the Pancreas), and Type II Diabetes (often a preventable condition where the body no longer responds properly to insulin).
CGMs allow users to monitor their Blood Glucose levels, continuously in near-real time and keep their glucose within healthy levels, and have transformed the lives of people that require extraneous insulin to manage their condition, and, if you ask me, hold a promise to do a lot more than that...
Diabetes Type II represent over 95% of cases of Diabetes in the world, and its incidence is rising and linked with what is called the "Obesity Pandemic". Evidence is mounting that the metabolic and other health changes that lead to Type II Diabetes lead to a whole host of preventable chronic diseases.
Research shows that most of these preventable conditions are the result of impaired metabolism, oxidative stress and other damage to our bodies that accumulate as we age and are accelerated by sedentary and unhealthy lifestyles. And as for the prevention strategy: you guessed - a healthier lifestyle.
Research also points to the Insulin Resistance being a major precursor to most of these preventable conditions, and very strongly linked to higher risk and later incidence of obesity, high blood pressure, high cholesterol, Type II Diabetes, Cardiovascular disease, Dementia & even some forms of Cancers!
Now, measuring Insulin Resistance (which requires measuring insulin) is not easy, but blood glucose, the compound it controls, is, and we can do it continuously with a CGM!
A window into your Metabolism
Continuous Glucose Monitors give us a new instrument for self-knowledge, a window into our metabolism, into how our body reacts to what we eat do & feel, and provide a wealth of data about what is making us sick, and what we can do about avoiding it.
The ancient greek aphorism"Know Thyself" is powerful, but can be an unstoppable force of change when self-knowledge meets action. Imagine what you could do if you could know exactly what is making you sick, how it is making you sick, and you could just check and see the effect of everyday food, activity & habits real-time?
Now that you get my enthusiasm for the use of CGM in the process of "knowing thyself" and taking action to improve your wellbeing, health and avoiding preventable disease lets look at what to look for, what to aim at, and how you can get started!
How do CGMs Work?
Current CGMs work by measuring the glucose in your interstitial fluid, generally by inserting an implantable probe or sensor within your skin which communicates wirelessly to your SmartPhone via NFC or Bluetooth.
The measurements are not of direct of blood glucose, but of the interstitial fluid that is then used to estimate blood glucose levels using algorithms.
Most sensors are self-applied with an applicator that makes the process painless and easy and have a useful life of 10-14 days, at which time you need to discard it and a new sensor applied.
A word on precision & Diagnosis
That said, CGMs provide continuous measurements which allow us to see dynamic behaviour of out metabolism to things like food, sleep & exercise, something not pratical with blood tests.
The availability of continuous data also allows individuals to track trends and experiment with different interventions (e.g. dietary, exercise, etc) and see how these improve Glycaemic regulation in the short, medium & long-term.
It Raises and Falls
Yep, Blood glucose raises and falls, simple right! Just kidding :)
Blood Glucose is measured in terms of its concentration in your bloodstream, either in milligrams per decilitre (mg/dL), or in millimoles per Litre (mmol/L). Your Blood Glucose concentration will vary during the day as result of natural metabolic processes, food, exercise, sleep, medications, etc.
Blood Glucose is one of those "2 sides of the same coin" things in life, but one that is life-sustaining but that can also be fatal in excess, so your body employs complex mechanism to ensure you always have a healthy level of glucose to feed your organs & sustain a healthy metabolism, and works extremely hard to ensure it never gets to unhealthy levels (too low glucose can starve your body; too much glucose is toxic and kills cells). If you want to know more you can read a longer post on Blood Glucose here.
Now let's look at how your Blood Glucose changes, what may cause it to change.
Macronutrients Ingestion & Blood Glucose
Blood Glucose normally raises as a result of ingesting food, mainly carbohydrates. Carbohydrates come in simple & complex forms.
Simple carbohydrates are composed of sugars and found in foods in natural form (e.g.: honey), but mostly in processed foods & ingredients (white flour, cakes, candy, sugar, fructose, etc). Simple sugars are readily processed into glucose in your digestive system, and absorbed into the blood, leading to faster rise of Blood Glucose.
Complex carbohydrates on the other hand are... more complex. They contain more complex sugar structures and are occur naturally in foods that also contain fibre and other macro & micronutrients. These characteristics makes the ingestion of complex carbohydrates by the body slower, and the resulting in smaller peaks in blood glucose. Additionally, foods containing complex carbohydrates are more nutritious compared to the simple carbohydrates.
Consuming protein and fat also raises your blood glucose but the magnitude of the increase is orders of magnitude smaller.
On top of this different people metabolise foods differently and you yourself may have different Glucose Response from day to day depending on how well you slept, your level of stress, if you had a more carb-laden breakfast than usual, or exercised before or after the meal.
Yep! It can gets complicated...
About Fasting Glucose
Fasting Blood Glucose is the concentration of Blood Sugar measured when you are in a fasting state (without eating or drinking anything but water for at least 8h) and is normally measured as part of blood tests. It is also the most recognised Blood Glucose metric and the main one used by physicians to pre-diagnose diabetes.
- Optimum: Between 80-65 md/dL
- Normal: Below 99 mg/dL
- Pre-diabetes: 100-125 mg/dL
- Diabetic: 126 mg/dL or above on at least 2 measurements
An estimation of Fasting Blood Glucose can be measured with CGMs by averaging the glucose measurements between 8h fasting and your 1st meal, but due to their precision CGMs cannot be used for diagnosis diagnosis, but you get a pretty good idea of where yo¡u are at...
What does a Healthy CGM data look like?
To start with you want your average Blood Glucose in fasting state (after 8h without eating and drinking) to be at or below 99 mg/dL.
Additionally, the International Diabetes Federation's guidelines for Management of PostMeal Glucose in Diabetes states that healthy people have glucose spikes resulting from food ingestion generally below 140 mg/dL, with glucose returning to pre-meal levels within two to three hours.
Complementing the guidelines above with other characteristics & parameters observed in the Glucose response of healthy individuals described in various studies [24, 25, 26, 27, 28], the following indicative healthy glucose regulation parameters can be drawn that will be observable by CGMs:
- Average Fasting Blood Glucose at or below 99 mg/dL.
- Average Blood Glucose of ~100 mg/dL, with lower night time averages;
- > 96% of the time Blood Glucose is in the range 70-140 mg/dL;
- Around 2% of time Blood Glucose is > 140 mg/dL;
- Around 1% of time Blood Glucose is < 70 mg/dL;
- Blood Glucose returning to pre-meal levels within two to three hours.
A simple way of visualising this is, in a 24h period having:
- Glucose mostly in a "Green Zone" (> 96% of the time in range 70-140 mg/dL);
- Glucose is in the "Red Zones" (> 140 mg/dL & <70 mg/dL) only during occasional "peaks & troughs" (totalling ~4% of the time).
- Glucose Plateaus while you sleep are at or below 99 mg/dL.
- Average Blood Glucose is ~100 mg/dL, with lower night time averages.
Note that these are not clinical recommendations, but should give you and idea of what "healthy" looks like.
Not the whole Story
Blood Glucose is not the whole story, measuring it does not provides us with how the whole metabolism is working, is not a direct measurement of insulin.
But it tells a whole lot more than not knowing it, plus, the fact that we can have a continuous gage on it and correlate it with other metrics (e.g.: heart rate) multiplies its power & possibilities of use.
What can I do with this information?
If your blood glucose is within the parameters described above then just keep doing what you are doing!
Otherwise, if you consistently and significantly fall outside the indicative values above then you are probably at increased risk of having or developing Type II diabetes, and in that case at a higher risk of developing other chronic disease, and so should talk with your doctor.
Chances that you are an undiagnosed diabetic are not high, but are higher of being outside the "healthy bracket" and be a pre-diabetic, or in the process of becoming one. In this case do not despair, in the majority of cases you can improve your glyceamic response with lifestyle changes that will impact other parts of your life, for the better.
Even if you are diagnose with Type II diabetes, know that the same lifestyle changes can improve your glyceamic response and reverse this condition.
How to get Started?
You can purchase a CGM yourself and experiment, logs, a diary and data, and get to know your glycemic response during the day, how your diet, eating patterns and habits affect your blood glucose, and even how your sleep, exercise and emotional state affect your metabolism.
If you get really into it you can devise a nutritional plan and habit changes to improve your metabolic response and start your journey towards better health and a longer life with lower risk of chronic disease.
If, like many of us, you cannot fathom how you would get time to do all this, and want to take this to the next level you can Join Kognitas!
- Continuous Glucose Monitors (CGMs) were developed to aid in the management of Diabetes Mellitus but hold a promise to do a lot more than that;
- CGMs provide a new instrument for self-knowledge, a window into our metabolism, into how our body reacts to what we eat do & feel;
- Consuming protein and fat also raises your blood glucose but the magnitude of the increase is orders of magnitude smaller.
- How your Blood Glucose responds to the consumption of food is.. complicated: The mixture of macronutrients, the sequence matters, and so does how well you slept, your level of stress, if you had a more carb-laden breakfast than usual, or exercised before or after the meal.
- Fasting Glucose lCategories: (80-65 md/dL); Normal:(below 99 mg/dL); Pre-diabetic (100-125 mg/dL) & Diabetic(<126 mg/dL)
- Your Glucose response is healthy if you glucose is mostly in the "Green zone" (70-140 mg/dL) with only ~4% being outside it & your fasting glucose being at or below 99 mg/dL;
- If you consistently and significantly fall outside the indicative healthy values above then you are probably at increased risk of having or developing Type II diabetes and should talk with your doctor.
- Glyceamic response can be improved and Type II Diabetes can be reversed with lifestyle changes that will impact other parts of your life, for the better.
- Use of Continuous Glucose Monitors by People Without Diabetes: An Idea Whose Time Has Come? | link
- WHO Diabetes | link
- WHO Diabetes Prevention & Treatment | link
- Reversing Type 2 Diabetes: A Narrative Review of the Evidence | link
- WHO Noncommunicable diseases Prevention | link
- Insulin Resistance and Diabetes | link
- Insulin Resistance & Prediabetes| link
- Insulin resistance. A multifaceted syndrome responsible for NIDDM, obesity, hypertension, dyslipidemia, and atherosclerotic cardiovascular disease | link
- Insulin resistance and cancer: the role of insulin and IGFs | link
- Insulin resistance and cardiovascular disease | link
- Insulin Resistance in Alzheimer's Disease | link
- Assessing Insulin Sensitivity and Resistance in Humans | link
- Physiological reconstruction of blood glucose level using CGMS-signals only | link
- Macronutrient Composition and Food Form Affect Glucose and Insulin Responses in Humans | link
- Impact of Nutrient Type and Sequence on Glucose Tolerance: Physiological Insights and Therapeutic Implications | link
- Personalized Nutrition by Prediction of Glycemic Responses | link
- The Effects of Breakfast Consumption and Composition on Metabolic Wellness with a Focus on Carbohydrate Metabolism | link
- Sleep and Blood Glucose Levels | link
- Blood Sugar Levels & Exercise | link
- Can Stress Cause High Blood Sugar? | link
- How Blood Sugar Can Change Your Body & Brain | link
- Mayo Clinic - Diabetes | link
- 2011 Guideline for Management of PostMeal Glucose in Diabetes | link
- Continuous Glucose Monitoring Profiles in Healthy Nondiabetic Participants: A Multicenter Prospective Study | link
- Reference Values for Continuous Glucose Monitoring in Chinese Subjects | link
- Variation of Interstitial Glucose Measurements Assessed by Continuous
Glucose Monitors in Healthy, Nondiabetic Individuals | link
- Continuous glucose monitoring is more sensitive than HbA1c and fasting glucose in detecting dysglycaemia in a Spanish population without diabetes | link
- Characterizing glucose exposure for individuals with normal glucose tolerance using continuous glucose monitoring and ambulatory glucose profile analysis | link