The very basics of Insulin: what Masters Crossfit and people in general should know.

This post is in response to stuff we overhear, or see repeated on CrossFit affiliate websites, or are told by well-meaning individuals:  The message we keep encountering is that insulin is bad.  A quote that seems to have been copied and pasted to a number of different sites is “insulin makes people sedentary” and it has been attributed to Dr. Robert Lustig.  If he wrote this, it was probably taken out of context and then confused.  That sort of thing happens all the time.  Or there might have been a typo at some point.  (The statement does bring up some thoughts as to how you could test to see if insulin makes people sedentary.  Inject them and see if they decided they’d rather stay home and watch TV or go for a walk?  You might cause their blood sugar to plunge, which might pull the floor out from under them and send them into a coma, but that’s not the same thing as becoming sedentary.  At least not in the context of exercise and fitness.)

Future CrossFit Dude and EMT with his Dad.

Insulin gets sugar out of your blood stream, and keeps it from damaging your blood vessels.  This is important.  If your fat cells are full, or otherwise stressed, they may stop responding to insulin.  They are protecting themselves (Hoehn et al. 2009) possibly at the expense of other types of cells.  The result is that sugar stays in your blood stream. This is what is bad, especially since this can easily become a chronic condition.

Insulin is part of a system that keeps your blood sugar stable.  You want just enough.  Not too much sugar which will cause damage.  Not so little sugar that there will not be enough energy available to keep you walking around.  You need the entire system to function well.  Its system health that matters. Trying to stop one part from doing its job is not going to help.  What you can do to help your body regulate itself, and keep things from spiraling out of control, is to eat well, keep stress at manageable levels, and exercise.   Avoid long periods of sitting too.  You can be a high performer at the gym, but its hard to be active all day long if you have a desk job.  Get up and move around a little, especially after meals (Dunstan et al. 2012).  Even this little bit of effort will help lower blood glucose after a meal, and reduce your body’s need to put out more insulin response (at least in Masters).  You will be keeping your body from having to deal with chronic overloads, which will wear it out (Ceriello et al. 2008), and allow it to keep running the system efficiently.  Again, its the system that matters, not insulin by itself.

Ceriello, A., Esposito, K., Piconi, L., Ihnat, M., Thorpe, J., Testa, R., Boemi, M., & Giugliano, D. (2008). Oscillating Glucose Is More Deleterious to Endothelial Function and Oxidative Stress Than Mean Glucose in Normal and Type 2 Diabetic Patients Diabetes, 57 (5), 1349-1354 DOI: 10.2337/db08-0063

Dunstan, D., Kingwell, B., Larsen, R., Healy, G., Cerin, E., Hamilton, M., Shaw, J., Bertovic, D., Zimmet, P., Salmon, J., & Owen, N. (2012). Breaking Up Prolonged Sitting Reduces Postprandial Glucose and Insulin Responses Diabetes Care, 35 (5), 976-983 DOI: 10.2337/dc11-1931  

Hoehn KL, Salmon AB, Hohnen-Behrens C, Turner N, Hoy AJ, Maghzal GJ, Stocker R, Van Remmen H, Kraegen EW, Cooney GJ, Richardson AR, & James DE (2009). Insulin resistance is a cellular antioxidant defense mechanism. Proceedings of the National Academy of Sciences of the United States of America, 106 (42), 17787-92 PMID: 19805130 ResearchBlogging.org

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