Pre-diabetes is a condition where fasting blood sugars are above normal but not yet in the diabetic range. Around 79 million people in the U.S. fall into this category. A normal, fasting blood sugar is less than 100 mg/dL. Above 125 mg/dL is diabetic, and values in between are in designated pre-diabetic. Pre-diabetes means your pancreas is struggling to produce enough insulin to get glucose into cells. Plus, it’s a harbinger of type 2 diabetes. In fact, 70% of people with pre-diabetes will develop type 2 diabetes at some point.
Blood sugars in the pre-diabetic range are a strong warning signal that changes must be made to avoid full-blown diabetes. Unfortunately, many people don’t know they have this condition and, even if they do, they often don’t take it seriously or treat it aggressively enough. Lifestyle changes are often effective for returning blood sugars back into the normal range and preventing progression to diabetes. Studies show that the rate of progression to diabetes within 3 years can be decreased by almost 58% through lifestyle changes alone. One of the most important of these is exercise.
Pre-diabetes is often associated with other abnormalities that make up the metabolic syndrome. These include elevated blood pressure, high triglycerides, low HDL-cholesterol, and a large waist size. The increase in waist size is due to the accumulation of visceral abdominal fat, the most unhealthy type of fat. That’s why pre-diabetes and diabetes are so strongly linked with cardiovascular disease. Anything we can do to bring these values into the normal range helps lower the risk of heart disease and stroke – and one of those is exercise.
Exercise and Pre-Diabetes
Exercise is an important lifestyle habit that helps bring blood glucose down. When you exercise, muscle cells demand more glucose. During exercise, they can even take up glucose without the help of insulin and, after a bout of exercise, insulin sensitivity is higher for several hours afterward. This means cells can take up glucose without the pancreas producing as much insulin. The insulin it does produce after a bout of exercise behaves more efficiently so that the pancreas doesn’t have to produce as much of it. That’s a positive for metabolic health and for blood sugar control. So, one of the ways exercise, particularly vigorous exercise, helps lower blood sugar and reverse pre-diabetes is by increasing the ease with which cells take up glucose.
But, that’s not the only benefit exercise offers for people whose blood sugar is running a bit too high. Exercise helps with weight loss and weight control as well. The most important risk factor for pre-diabetes and type 2 diabetes is obesity but even modest amounts of weight loss can help. Research from Johns Hopkins shows losing as little as 10% of body weight within six months of being diagnosed with pre-diabetes dramatically reduces the risk of developing type 2 diabetes.
What Type of Exercise is Best for Pre-Diabetes?
We think of aerobic exercise as being the most beneficial for blood sugar control. However, resistance training has its place in improving metabolic health and blood pressure control too. Studies show that strength training, even without dietary changes, improves glucose control in people with pre-diabetes. The reason? Muscle acts as a “sink” for glucose. The more muscle you have, the more glucose your muscle cells will take in to use for energy. When you contract your muscles during weight training, they suck up more glucose from the bloodstream.
Of course, aerobic exercise helps lower blood sugar too and also burns calories for greater fat loss. However, high-intensity exercise may have an edge over moderate-intensity exercise like brisk walking. For one, it’s better for reducing deep, visceral abdominal fat, the kind most strongly linked with pre-diabetes and diabetes. Take advantage of it! Rather than doing long, boring periods of cycling, walking, or running at the same speed, add some intense intervals to your fitness routine.
Combat Sitting Disease
Structured exercise helps bring down elevated blood sugars, but you also need to reduce the amount of time you spend sitting. Studies link sitting for more than six hours daily with an increase in markers that associated with pre-diabetes and diabetes, including high triglycerides, weight gain, a rise in blood pressure, and an increase in waist size. Even if you do a structured workout most days, break the cycle of sitting at home and work. Take walking and stretching breaks every 30 minutes at work, and don’t curl up in front of the television set when you get home from work. If you do watch television or work on a computer, exercise during commercials. Why not do a set of squats or some jumping jacks? When you sit too long, your muscle cells don’t take up as much glucose and it stays in your bloodstream longer. Movement, of all types, improves insulin sensitivity.
The Bottom Line
Research clearly shows that progressing from pre-diabetes to diabetes isn’t inevitable. Lifestyle changes make a difference and exercise is part of the equation. But, it’s important to take pre-diabetes seriously. By the time your blood sugars are elevated, you may have already sustained damage to blood vessels and nerves. Check your blood sugar regularly and ask your physician to measure a hemoglobin A1C. It measures blood sugar control over the past three months and is better than a single fasting blood glucose reading.
Watch your waistline, lipids, and blood pressure too. An expanding waistline, higher triglycerides, and a rise in blood pressure often go along with pre-diabetes. Know your family history too. If diabetes runs in your family, you’ll need to monitor even more closely, at least every six months. Finally, don’t forget to exercise! Exercise not only lowers blood sugar and improves insulin sensitivity, it reduces the risk of heart disease, the most common cause of death for people with diabetes.
National Institute of Diabetes, Digestive, and Kidney Diseases. “Prediabetes & Insulin Resistance”
Perm J. 2014 Summer; 18(3): 88–93.
Johns Hopkins Medicine. “People With Pre-Diabetes Who Drop Substantial Weight May Ward Off Type 2 Diabetes”
FP Essent. 2015 Aug;435:11-6.
WebMD. “How common is prediabetes?”