Thomas Lackie
Exercise is one of the most effective way to lower blood glucose.
One of the most effective way to lower blood glucose is by exercising. Muscle contraction relies on glucose for fuel. GLUT4 transporters are glucose transporters located within muscle cells. In a resting muscle, GLUT4 is mainly retained in intracellular vesicle structures by a recycling pathway that largely keeps GLUT4 in intracellular compartments and not inserted in the surface membranes [3]. Muscle contractions lead to the activation of AMPK, which increases the rate of exocytosis of GLUT4. Once GLUT4 is inserted into the plasma membrane, it can “suck up” glucose from the blood, providing the muscle cell with glucose, and lowering blood glucose (figure 1&2). Muscle contraction during exercise is a more potent physiological stimulus of skeletal muscle glucose uptake than even maximal insulin [3]. Acute regulation of muscle glucose uptake relies on GLUT4 translocation, however after training, there is an increase in GLUT4 transcription. Exercise is the most potent stimulus to increase skeletal muscle GLUT4 expression, an effect that may partly contribute to improved insulin action and glucose disposal and enhanced muscle glycogen storage following exercise training [3] (figure 3). I found some cool pictures that study [3] published.
Type 2 diabetes
In people with type 2 diabetes, inulin-stimulated glucose uptake in skeletal muscle is impaired. When insulin binds to an insulin receptor on a muscle cell, it will ultimately cause the translocation of glut 4 from its storage vesicles to the plasma membrane to uptake glucose from the bloodstream. If this is impaired, blood insulin and glucose levels remain high. We reviewed that exercise will cause the acute translocation of glut 4, while chronic exercise training improves mitochondrial function, increases mitochondrial biogenesis, and increases the expression of glucose transporter proteins and numerous metabolic genes [5]. Weight training would suffice, but also, research has been done on steady state cardio and HIIT cardio. On study took 14 people with type 2 diabetes, and 8 of them did 6 sessions of HIIT training over 2 weeks. They did 10×60’s, and during the 10 sec duration they achieved a 90% maximal effort and then recovered for 60 seconds with a 5-minute cooldown. After 2 weeks, they showed a significant decrease in blood glucose concentrations’ [4]. Another publication studied the levels of GLUT4 proteins expressed in type 2 diabetes patients after 6 sessions of HIIT cardio. GLUT4 content in the vastus lateralis increased by 369%.
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Figure 2
Figure 3
- James D.E., Kraegen E.W., Chisholm D.J. Muscle glucose metabolism in exercising rats: comparison with insulin stimulation. American Journal of Physiology. 1985;248:E575–E580
- https://www.semanticscholar.org/paper/Exercise%2C-GLUT4%2C-and-skeletal-muscle-glucose-Richter-Hargreaves/0d92ae886747190f1cb79b56277aae7aaf11f37d.
- Richter, E.A., & Hargreaves, M. (2013). Exercise, GLUT4, and skeletal muscle glucose uptake. Physiological reviews, 93 3, 993-1017.
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