Discover the role of Insulin and how to track it.

Insulin sensitive, that is? In the world of strength and conditioning, it is impressive to see the growing interest amongst coaches and athletes alike regarding their blood work and, more specifically, their ability to regulate glucose following a meal, an exercise bout, or upon waking.  While it is great that athletes have taken an interest in their metabolic health, the focus on blood glucose may be misplaced.  Acute changes in blood glucose are simply a small piece of the puzzle. What athletes and coaches are really interested in is a component of their endocrine (hormone) system that deals with regulating insulin secretion and insulin sensitivity.

While this blog is not intended as a deep dive into insulin ( I suggest you check out this blog all about hormones by my buddy and fellow Power Athlete Coach  Ben Skutnik), insulin is a peptide derived hormone (amino acid based) which is secreted from the pancreas. Since it’s peptide derived, it must communicate to cells via a second messenger that exists on the cell membrane. Think of it as a middle man. Insulin’s primary role is to regulate blood glucose, specifically making sure that blood glucose does not climb too high as this can result in hyperglycemia and be all types of bad if chronically elevated (1). Insulin regulates glucose, and other nutrients like amino acids, by communicating to the cell and getting glucose doors to open on the cell membrane using what is known as glucose uptake transporters (or GLUTs). When these GLUTs open up, glucose can rush into the cell and blood glucose levels drop back to baseline.

This is a KEY-POINT for the rest of this blog series. In theory, the faster insulin can communicate to the cell and get blood glucose back to baseline, the more Insulin Sensitive the individual should be.

That is essentially the big picture of insulin, but as part of the Power Athlete community, you have to ask yourself why you should care. Should you be tracking your glucose or insulin sensitivity and, if you do, what do you do with that information?

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Tracking and Data

First, why should you care? Insulin sensitivity and blood glucose regulation are two of the best predictors for your cardiometabolic health and risk for disease development. You want to be insulin sensitive throughout life. There is also an argument that since insulin is the most anabolic hormone in the body, the more insulin sensitive you are, the easier it should be to add lean muscle. I think the jury is still out on this one, but I will say it is hard to be insulin sensitive and not lean or sporting an optimal level of body fat for yourself. Look at most any hard-charging professional athlete and in most instances you’ll find an optimal level of body fat for their sport.  If you were to test them, you’d likely find a level of insulin sensitivity to go with their physique. So, let’s talk about how to assess it.

The truth is, it is nearly impossible to assess insulin sensitivity at home in a clinically relevant method. For example, I test for insulin sensitivity all the time in my research, but it requires ~100k dollars worth of equipment and another ~10k in blood hormone assay kits. You got that kind of money laying around? If you happen to get regular blood testing done and your physician measures insulin, then you can easily calculate insulin sensitivity (insulin and insulin sensitivity are not the same) using the Homeostatic Model Assessment for Insulin Resistance (HOMA-IR) method. Simply take your blood insulin levels (they must be in mU/L units so convert if not) and multiply by your blood glucose (in mg/dL) to get your HOMA-IR. See the ranges down below for interpretation of your insulin sensitivity.

Healthy Range: 1.0 (0.5–1.4)
Less than 1.0 means you are insulin-sensitive which is optimal.
Above 1.9 indicates early insulin resistance.
Above 2.9 indicates significant insulin resistance.

What if you do not get regular blood work and you do not have any insulin values to go off of? Are you doomed? No, and there are some other methods in which you can assess and make some fairly strong interpretations based on how your data come back.

Continuous Glucose Monitors (CGM) – CGM are monitors that go on the arm and can track your daily blood glucose levels by the second for usually a 2-week period. They are, however, expensive and difficult to obtain pending the state you live in. I honestly did not think I’d see the day when Power Athletes were asking me about CGM and what their data meant. The truth is – we are still learning exactly what it means when a person experiences a blood glucose spike from a food item and how to interpret this. Research has shown that one person can experience a dramatic spike in blood glucose from a cookie and not from a banana. Yet, another individual can have the exact opposite effects (2). Is one person healthier than the other? We are not sure, and it appears this is all tied back to the gut microbiome. So, while CGM can give you a snapshot of your blood glucose at any time during the day, the truth is we still are not sure what those data mean.  Unless you are a Type 1 Diabetic or obese, feel free to find and use a CGM, but there are better ways to assess what we are focused on in this blog.

Glycated Hemoglobin – Also known as HbA1c, glycated hemoglobin reflects the average amount of glucose your red blood cells were exposed to over the duration of their lifecycle (about 90 days). This is an excellent marker to obtain from a blood panel test if you can get it, but again, this can be rather difficult or expensive to obtain at home. In general, HbA1c can give you an idea of how well you are regulating blood glucose. The higher your HbA1c, the more blood glucose your red blood cells have been exposed to. In theory, the more insulin sensitive an individual is, the quicker they can regulate and bring glucose levels back down to the normal range, which should bring someone’s HbA1c levels down as well. Lower is typically better with regard to this marker.

Ranges
Less than 5.7% is optimal.
5.7-6.4% indicates early insulin resistance.
>6.4% indicates significant insulin resistance

Blood Glucose Monitors – Cheap and accurate, this is the method I would recommend you going with at home (specifically the Precision Xtra brand). Blood glucose monitors are simple in that you just need to prick your finger (after sterilizing it, of course) and then analyze a drop of capillary blood to determine your current and acute blood glucose levels.

Ranges

While this is no different than the CGM I mentioned earlier, the method I outline in Part 2 is what allows you to get a rough idea on insulin sensitivity. This test is the oral glucose tolerance test, and while this blog is not intended to serve as a replacement for your physician or to be treated as medical advice, the methods I outline will allow you to get some idea of your overall metabolic health from the comfort of your home.

References:

1.      Reaven, G. M. (1988). Role of insulin resistance in human disease. Diabetes, 37(12), 1595-1607.

2.      Zeevi, D., Korem, T., Zmora, N., Israeli, D., Rothschild, D., Weinberger, A., … & Segal, E. (2015). Personalized nutrition by prediction of glycemic responses. Cell, 163(5), 1079-1094.

RELATED CONTENT:

BLOG: A COACH’S FIELD GUIDE TO HORMONES

PODCAST: EP 726 – WELLCORE’S DIABETES BATTLE AND HORMONE INSIGHTS

EDU: POWER ATHLETE METHODOLOGY

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