Growth doesn’t occur without resistance of some kind. Sometimes the strongest resistance we face when pursuing change is from ourselves. How do you feel when you think of going back to school, joining the gym, losing weight, or apologizing for a wrong? That’s resistance. How do we surmount the thoughts and feelings, the negative self-talk, and distractions that hinder us from conquering resistance?
We’ve been looking at insulin resistance for the past few months and identifying why the body launches an internal resistance to insulin. This month we’ll look at another factor that is, unfortunately, extremely common.
Kentucky is ranked as the most physically inactive state, while Colorado is the most physically active. Interestingly, Kentucky is also among the states with the highest prevalence of type 2 diabetes. Guess where Colorado ranks? It has the lowest prevalence of type 2 diabetes compared to the rest of the US.1-3 Research has shown that this is no coincidence.
Twenty healthy, non-smoking adults were put on bed rest for five days. During that time researchers measured insulin sensitivity and compared it with measurements taken when the adults were not on bed rest. The researchers observed a 67% increased insulin response to a glucose tolerance test after five days of being completely sedentary. In other words, after bed rest, researchers found that a whole lot more insulin was needed to handle the blood sugar surge from a sugary drink. In addition, significant increases in total cholesterol, LDL cholesterol, triglycerides, insulin levels, and the HOMA-IR test (a method of measuring insulin resistance) were all observed after the stint of bed rest. Just five days of inactivity created this state of insulin resistance in the volunteers, along with observed blood vessel dysfunction.4
A European study evaluated the impact of physical inactivity on healthy adults. Involved in the study were 346 men and 455 women, ages 30-60 years old. The participants wore accelerometers, which measured the level of physical activity for an average of six days. These devices tracked the intensity and duration of physical activity and inactivity. Insulin sensitivity was measured using a testing method called the hyperinsulinemic-euglycemic clamp. In the most sedentary—those with more than 68 percent of their time sedentary—“there was a highly significant relation between insulin sensitivity and total activity.”5 The intensity of exercise did not have as great an impact on insulin sensitivity as the total amount of time engaged in any level of activity. While research has shown that dose and intensity of exercise impacts insulin signaling in skeletal muscle cells, the turtle still comes up a winner just by finishing the race. In contrast, long periods of inactivity have the reverse effect of increasing insulin resistance.
An Australian study tracked 6,241 adults who were 35 years of age and older and without diabetes or heart disease. In it, insulin resistance was compared with hours of TV watching. Interestingly, insulin resistance was positively associated with those who watched over 14 hours of TV per week, whereas engaging in some form of physical activity over two and a half hours a week was associated with a reduction in insulin resistance in both genders.6
The body was designed to move and when it doesn’t, changes in cellular communication with insulin occur.
The Nurses’ Health Study is one of the largest studies conducted with women, and is currently following its third generation of women. From this ongoing study, researchers have found that the number of hours spent sedentary is positively related to incident diabetes, even after adjusting for total physical activity. In other words, we need to make time for activity at different times during the day. Going for a walk in the morning and then sitting for the rest of the day may not be enough.
Are you getting the picture? Not exercising, sitting for hours on end, and even TV watching, promote insulin resistance. Some researchers have observed this to be true outside of its impact on weight. The body was designed to move and when it doesn’t, changes in cellular communication with insulin occur. Exercise even without weight loss improves insulin sensitivity. Some researchers have demonstrated that just one bout of exercise improves insulin sensitivity 40% and the benefit can last for a couple of days.
Is the reverse true? Can the body become more insulin sensitive by increasing physical activity? Yes! Physical activity is one of the most powerful ways to resist insulin resistance.
The accumulated results of 14 different studies showed that insulin resistance improves when individuals with type 2 diabetes exercise. Twelve of the studies used aerobic exercise. Two studies used resistance training. While body mass did not significantly change over the course of these studies, the blood marker that measures average blood sugar levels over a three-month period (HbA1c) was reduced. Exercise lowered blood sugar levels.7
An analysis of the Finnish Diabetes Prevention Study, discovered that engaging in at least two and a half hours a week of walking for exercise, “in comparison with less than 1 hour, was associated with a 63–69% lower risk of incident diabetes.”8
Sounds like some resistance training would do us good. The question, however, is how can we progress from information to transformation? Knowing how important physical activity is, is only valuable if it translates to action. Launching a counter-resistance to insulin resistance is going to require more than Metformin. I wonder if the first step to launching a counter-resistance is realizing our internal locus of control, rather than seeing ourselves as helpless victims of diabetes. An internal locus of control is acknowledging the power of the will. Resistance can make us stronger if we are willing to resist it.
- Naomi M Hamburg et al., “Physical Inactivity Rapidly Induces Insulin Resistance and Microvascular Dysfunction in Healthy Volunteers,” Arteriosclerosis, Thrombosis, and Vascular Biology, vol. 27,12 (2007): 2650-6, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2596308/.
- Beverley Balkau et al., “Physical Activity and Insulin Sensitivity: the RISC study,” Diabetes, vol. 57, 10 (2008): 2613-8, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2551669/.
- D. Dunstan et al., “Associations of TV viewing and physical activity with the metabolic syndrome in Australian adults,” Diabetologia, (2005)48(11):2254-61, https://www.ncbi.nlm.nih.gov/pubmed/16211373.
- N.G. Boulé, E. Haddad, G.P. Kenny, G.A. Wells, and R.J. Sigal, “Effects of Exercise on Glycemic Control and Body Mass in Type 2 Diabetes Mellitus: A Meta-analysis of Controlled Clinical Trials,” JAMA, 2001;286(10):1218–1227, https://jamanetwork.com/journals/jama/article-abstract/194184.
- David Laakson et al., “Physical Activity in the Prevention of Type 2 Diabetes,” Diabetes, 2005;54(1):158-165, https://diabetes.diabetesjournals.org/content/54/1/158.
- Venkatasamy, Vighnesh, Vetrivel et al., “Effect of Physical Activity on Insulin Resistance, Inflammation and Oxidative Stress in Diabetes Mellitus,” Journal of Clinical and Diagnostic Research, JCDR, vol. 7,8 (2013): 1764-6, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3782965/.
- Naomi Hamburg et al., “Physical inactivity rapidly induces insulin resistance & microvascular dysfunction in healthy volunteers,” Arteriosclerosis, Thrombosis, and Vascular Biology, (2007);27:2650–2656, https://www.ahajournals.org/doi/full/10.1161/atvbaha.107.153288.
Risë Rafferty, RDN
Risë is a Registered Dietitian Nutritionist (RDN) and has been writing and teaching about health for many years. She loves the health message and takes great pleasure in seeing people thrive by the application of its principles. Her research and down-to-earth manner allow her to offer up the health message in both an intelligent and accessible manner. She and her husband, James Rafferty, have two children.