In Barbell Medicine podcast 174, Drs. Baraki and Feigenbaum review a meta-analysis study that evaluated the effect of resistance training on blood sugar A1c in adults with diabetes. Blood sugar A1c is a marker used to assess average blood sugar levels in an individual over the past three months. The paper concluded that adherence to resistance training dropped the concentration of blood sugar A1c by 0.4%. The study noted that individuals who gained more strength were more likely to see a significant reduction in blood sugar A1c values. This observation suggests a correlative relationship between strength and blood sugar, and my immediate conclusion was that more strength means more drop in blood sugar A1c. Yet, Baraki states that it would likely be erroneous to conclude that strength is what drives the reductions in blood sugar A1c. The more probable explanation is that increased strength and a decrease in blood sugar A1c are both outcomes of a well-matched training program.
In weight training, the number of repetitions an individual can perform a specific movement with a given mass is an easily evaluated measure of strength. If strength increases throughout the training program, it can be assumed that the training dose promotes adaptation in the body. This general adaptation to the specific stressor of resistance training drives the fitness-specific adaptions of strength and muscle development. The same mechanisms that promote strength can also promote non-strength-related outcomes like improved mood and possibly a decrease in blood sugar A1c. This implies that blood sugar A1c can be seen as a marker of the effectiveness of the training program much like strength. Both are outcomes of the adaptation to the training.
I found this flipped conclusion rather inspiring. Training to promote adaption in your body has wide-reaching benefits due to the share mechanisms of adaptation. We monitor for changes in strength, but it’s not the strength that makes us healthier. The progress of adaptation drives all the measured and unmeasured outcomes in our bodies.