My new book, Deep Fitness: The Mindful, Science-Based Strength-Training Method to Transform Your Well-Being in 30 Minutes a Week, coauthored with Philip Shepherd, is coming out on October 12, 2021. The following is an adapted excerpt from the book. If you want to learn more, pre-order now!
One of our clients, Chris, turned up at NET after bloodwork had revealed his A1C levels to be dangerously high. An A1C test result reflects your average blood sugar level for the past couple of months. A reading above 5.7 is considered pre-diabetic, and Chris was at 8.2.
But after four months of training with us and watching his diet, Chris had another test. His endocrinologist was amazed: his A1C levels had dropped from 8.2 to 6.7. On the day of the test, his blood glucose measured 5.9.
It’s predicted that by 2050 one in three American adults will have diabetes. Could strength training be a way to help reverse diabetes?
One randomized controlled trial recruited obese, older adults who were prediabetic, and supervised them through two strength-training sessions a week for three months. At the end of that period, 34% had achieved normal glucose tolerance, even though they remained obese.
Another compelling study involved adults with type 2 diabetes who participated in five to six aerobic training sessions a week, and two to three strength-training sessions a week. After a year, 75% of the participants were able to reduce their glucose-lowering medications, and 56% had gone off them completely.
Evidence has emerged that resistance training may be more effective than aerobic exercise at improving insulin sensitivity and lowering blood-glucose markers.
How it works
Sugar occurs naturally in the blood. But if blood carries too much sugar, glucose can damage cell structures and the vessels that supply blood to our vital organs. Over time, that damage increases the risk of heart attack, heart disease, kidney disease, skin problems, and damage to the eyes, nerves, and brain.
Insulin regulates sugar in the blood. Blood sugar tends to rise after we eat carbohydrates, and so insulin is released to convey glucose into cells that need it and to remove excess glucose from the blood and put it into storage for later.
There are two main ways of storing excess glucose. Some is stored in the form of glycogen; around 80% of glycogen is stored in the muscles. But the lower your muscle mass is, the less storage space you have for glucose. And the second way of storing glucose is converting it to fat.
That means that two people could have two different outcomes after eating the same meal: a person with healthy muscle mass can absorb most of the surplus glucose into the ample storage of the muscle; a person with low muscle mass will convert much of that glucose to fat.
Over time, eating lots of carbs without maintaining or building muscle not only leads to fat gain, it diminishes the effectiveness of insulin. Our insulin receptors, which are found mainly in muscle cells, start losing their ability to respond appropriately to insulin. As insulin resistance worsens, it becomes the chronic disease we know as diabetes.
But this process is not inevitable. As a 2019 Annual Review of Physiology paper states, "type 2 diabetes may represent a reversible chronic disease and . . . exercise as medicine may be as efficient as a glucose-lowering medication."