Exercise and Diabetes: An Interview with Richard Parker
- Created on January 8th, 2013
- By Richard Parker, B.S., N.A.S.M. Master Trainer: Special Populations
As a National Academy of Sports Medicine [N.A.S.M.] Approved Continuing Education Provider, Richard Parker has developed and teaches a comprehensive course on Exercise and Special Populations for trainers seeking continuing education credits in this specialized fitness field. In addition, he conducts client forums in the Washington, DC region on Exercise and Diabetes.
Special Populations Overview
In fitness, the term Special Populations refers to anyone who presents a greater challenge to exercise and exercise training than is reasonably expected of the general population. This would include individuals who are elderly, have M.S., suffer chronic low back pain, are pregnant, significantly obese, or, as discussed below, those who have been diagnosed with Type 1 or Type 2 diabetes.
The Epidemic of Diabetes
One of the most formidable healthcare challenges today is type 2 diabetes. Unlike type 1 diabetes, which is a failure of the pancreas to produce sufficient levels of the hormone insulin as a of result organ dysfunction, Type 2 diabetes is a chronic condition that is brought on by a convergence of poor lifestyle choices. While Type 2 diabetes can largely be avoided, it continues to march through our society like some indomitable virulent plague bent on destroying mankind one amputated limb at a time.
Diabetes directly affects 25.8 million Americans while an estimated 79 million over the age of 20 are prediabetic. That's a total of 104 million people, or 1 in 3 Americans, facing the consequences of diabetes. This disease is the leading cause of kidney failure, blindness, and non -traumatic amputation in the U.S. It is a major cause of heart disease and stroke and is the seventh leading cause of death.
National Diabetes Fact Sheet,  www.cdc.gov
Considerations for Exercise & Diabetes
Diet is the most important component of diabetes management but exercise is a critical complement. All too often "dieting" is used to control this disease only to prove unsustainable and ineffective. Constant dieting results in the loss of lean mass or muscle tissue critical in enabling the body to regulating blood glucose or sugar.
Muscle tissue is ultimately where the greater amount of glucose in our bodies is stored to meet the energy needs of movement and life. Additional glucose is stored in the liver as glycogen and serves as a reserve to keep blood glucose from falling too low resulting in hypoglycemia. Maintenance of muscle tissue is uniquely one of the major benefits of exercise, which is why exercise, particularly resistance or strength training, is essential to any attempt to manage this disease.
This is where understanding which exercises are best for this condition becomes very important and is often a consideration lost to individuals with the disease and their healthcare providers alike. Educated and Certified fitness professionals such as myself better understand this because we are required to stay current in the science and practice of fitness training to maintain our professional certifications. We know all too well that each condition under the heading of Special Populations, including diabetes, presents an increased challenge of injury or worse if exercise is not administered or practiced knowledgeably.
For example, diabetes and the medications that are often prescribed for it can interact with exercise in several ways, some of which can be deadly. Delay Onset Hypoglycemia [D.O.H.] can occur hours after a diabetic exercises and essentially is the synergism of exercise and medication to lower blood glucose. Hypoglycemia can eventually result in diabetic coma and, if allowed to persist, death.
"Delayed-onset hypoglycemia is a phenomenon that occurs typically between 6 and 15 (some studies even suggest up to 30 hours) after cessation of exercise. Clients are at the highest risk when you start to increase the intensity or duration of their exercise program." [Darryl E. Barnes, MD]
A second adverse reaction to exercise that can occur is Diabetic Ketoacidosis [D.K.A]. Generally a complication for type 1 diabetics, D.K.A. develops as a result of an insufficient insulin level that may result from dehydration during exercise, excessively low carbohydrate diets, stress, fasting, or a combination thereof. The body defers to fat, muscle, and liver tissue for fuel resulting in an excess of a by product called ketones which can eventually overwhelm the kidneys, lower blood pH, and result in coma or death.
These are just some of the reasons why it is so important that individuals who have significant health or medical challenges choose to work with a certified fitness professional. It is vitally important that an individual who is considering a new exercise regimen consult with their doctor before beginning. If they have any significant challenges they should receive a written Medical Clearance from their doctor stating any concerns or cautions. The Special Populations fitness professional may even contact that doctor to clarify and discuss any concerns.
Exercise is not the purview of the doctor but the fitness professional. Both must work together from their perspective fields to insure the best and safest outcome for the patient/client. This is why supervised exercise is the safest and most effective way to meet many of the chronic health concerns of the day as most individuals don't have the background or education to go it alone.
Diet & Exercise vs. Medication
Nevertheless diet management and exercise, once properly administered has proven more effective than medication when dealing with type 2 diabetes. In one three year N.I.H. study involving nearly 3000 prediabetic individuals, 22% of those taking the drug Glucophage developed full blown diabetes while only 14% of those using diet and exercise did so.
U.S. News and World Report  by Josh Fischman
In another study several other medications were compared to diet and exercise. Acarbose, Metformin, and Troglitazone, and were each found to delay the onset of diabetes in prediabetic patients by 25%, 31%, and 41% respectively. Nevertheless, intensive lifestyle modification with regards to diet management and exercise quality was show to delay conversion to full diabetes mellitus by 58%. [Irons, B.K. et. al. 2004]
It has generally been assumed that the most effective way to avoid the development of diabetes or manage it once it is diagnosed is with aerobic exercise and diet, without much consideration for resistance exercise. Unfortunately this cannot be further from the truth for many who are diabetic or prediabetic.
Aerobic exercise has indeed been shown to enable the body to consume excess blood sugar by increasing metabolic rate during exercise and for some time during the post exercise state. In fact, in a most recent study meant to better understand the mechanism of how aerobic exercise achieves this goal it was found that running promoted a cellular process called autophagy.
Autophagy is essentially a process by which cells in our body clean away waste and debris that accumulates within the cell as it performs the functions of life. More importantly, when this process was removed the body no longer had the ability to affect and control diabetes with exercise. [Levine B. et. al. 2012]
In spite of the documented benefits of aerobic exercise, one of the major shortfalls of an aerobic and diet centered approach when attempting to manage diabetes is the lack of muscle building, and worse the risk of accelerated muscle wasting. According to David Dunstan of the International Diabetes Institute in Victoria, Australia, "...The medical community places less emphasis on physical activity than on diet when managing diabetes. When exercise is recommended, it often is of the aerobic variety...which can be difficult for older adult who face age related muscle loss..." Resistance training by the Australian researchers was found to be as effective as medication in controlling type 2 diabetes. Diabetes Care, Washington Post
Resistance exercise maintains muscle mass and improves it's effectiveness, or insulin sensitivity, for absorbing blood sugar out of the bloodstream. A more recent and direct study comparing aerobic and resistance exercise in their effectiveness to improve insulin sensitivity concluded that "Both aerobic exercise and resistance exercise alone are effective in reducing abdominal fat and intrahepatic lipids in [the study subjects]. Resistance exercise but not aerobic exercise is also associated with significant improvements in insulin sensitivity. [Lee S. et. al. 2012]
From these findings I think it becomes clear that as effective as exercise may be in its ability to combat type 2 diabetes, the exercise scheme used must be well thought out in both planning and implementation. The proper balance of resistance exercises and aerobic exercises with diet management is key.
Each individual is different though they may share a common malady. It's imperative that whatever exercise regimen is employed to help them navigate their Special Populations challenges be individually suited to meet those needs. Of course there is much more to this story, but it's clear that the power to curtail one of the most pervasive chronic conditions of our time is indeed in the will and hands of the people. Diabetes not only limits the length of your life but can destroy the quality of your life for years before it's done! Get up, get help, and do it right!
Levine B, He C, Bassik MC, Moresi V, Sun K, Wei Y, Zou Z, An Z, Loh J, Fisher J, Sun Q, Korsmeyer S, Packer M, May HI, Hill JA, Virgin HW, Gilpin C, Xiao G, Bassel-Duby R, Scherer PE, and (26 January 2012) Exercise-induced BCL2-regulated autophagy is required for muscle glucose homeostasis, Nature 481: p. 511-515 doi:10.1038/ nature10758
Lee S, Bacha F, Hannon T, Kuk JL, Boesch C, Arsianian S, (2012) Effects of aerobic verses resistance exercise without caloric restriction on abdominal fat, intrahepatic lipids, and insulin sensitivity in obese adolescent boys: a randomized controlled trial Diabetes 61(11): p. 2787-2795 doi: 10.2337/db12-0214