Farrell, Ph. People with diabetes must use extra vigilance in preparing for exercise because they lack insulin Type 1 DM or because the insulin they have is defective in its ability to stimulate glucose uptake Type 2 DM. Normal production and action of insulin are critical to a "correct" metabolic response to exertion.
The person with diabetes can, however, reach marvelous levels of physical accomplishment, and outstanding examples of this fact are found in most college, professional and Olympic sports. One of the most impressive of these athletes is Sir Steven Redgrave, winner of gold medals in rowing for Great Britain at five successive Olympic Games from to He was diagnosed with diabetes about two years before the Sydney Olympic Games.
Type 1 DM is characterized by an autoimmune destruction of pancreatic beta cells, i. Type 2 DM is very different from Type I DM; insulin is present, but it does not function efficiently to stimulate glucose uptake into cells termed "insulin resistance". The body tries to compensate for this defect by secreting more and more insulin, but eventually the reserve capacity of the pancreatic beta cells declines and the glucose concentration in the blood rises.
It is standard practice to follow the initial diagnosis by more extensive and repeated testing. In contrast to most hormones, concentrations of insulin in the blood decline during exercise in people without diabetes because less insulin is secreted from the pancreas. Given that skeletal muscle is quantitatively the most important tissue in the body for glucose uptake, especially during exercise, and given the fact that insulin is the primary stimulus for glucose uptake into resting cells, this decline in insulin secretion during exercise at first seems paradoxical. However, the insulin requirement for glucose uptake diminishes during exercise, because muscle contractions per se stimulate glucose uptake into muscle even when insulin is absent Hayashi et al.
The natural decline in insulin during exercise is necessary to prevent hypoglycemia. For people with Type 1 DM who appropriately manage their blood glucose levels and have adjusted their pre-exercise insulin dose, the fuels used during exercise are not markedly different from fuels used by nondiabetics, as long as the exercise intensity is moderate Raguso et al. The normal decrease in blood insulin during exercise in people without diabetes and in those with Type 2 DM allows the two most important fuels for exercise, carbohydrates and fats, to be mobilized and used by muscle.
High concentrations of insulin suppress the ability of the liver to release glucose and deliver it into the plasma. Elevated insulin also inhibits the release of fatty acids into the blood from adipose tissue and perhaps from fat stored in muscle. Unfortunately, the normal decline in insulin cannot occur in people with Type 1 DM because they cannot produce and therefore cannot decrease insulin production. Thus, the prevailing concentration of blood insulin depends on the timing of the last insulin injection or infusion rate for those who use an insulin pump.
Consequently, the ability to mobilize fat and carbohydrate fuels for exercise may be compromised in people with diabetes. Insulin in the blood must be at low levels during exercise, but maintaining at least some circulating insulin is an absolute requirement for other aspects of exercise metabolism that are discussed below. The following comments pertain to people with Type 1 DM or those with Type 2 DM who must use insulin to control their blood glucose. Over-insulinization , i. In the case of exercise, the most critical insulin target tissue is skeletal muscle, and muscle requires less insulin during exercise.
Even with what appears to be an appropriate reduction in the pre-exercise insulin dose, over-insulinization can still occur because contractions make the muscle more sensitive to insulin. Compounding the issue further, exercise increases muscle blood flow and heat production, both of which may enhance the absorption of injected insulin.
An overarching guideline is that the dose of insulin administered before exercise should be reduced. The amount of that reduction should take into account many factors, such as training status, time of exercise after the last meal, intensity and duration of exercise, and the extent to which the activity to be performed that day is habitual or unaccustomed. Under-insulinization can result in excessive concentrations of blood glucose hyperglycemia during exercise because very low insulin concentrations are insufficient to inhibit glucose release from the liver.
This concern is probably more pertinent to brief, high-intensity exercise such as occurs in many athletic contests as opposed to prolonged moderate-intensity exercise.
Additionally, other hormones, especially glucagon secreted by the pancreas and epinephrine adrenaline from the adrenal glands, become more effective in stimulating glucose production when insulin is too low Cryer, During low-intensity or prolonged exercise, fatty acids become an important source of energy for the active muscle. Overinsulinization will inhibit fatty acid release from fat stores, whereas underinsulinization will allow an excessive mobilization of fatty acids, which can cause ketone production and release by the liver, a condition called diabetic ketosis.
Ketones are acids that markedly increase the acidity of body fluids and thus must be avoided. It is impossible to provide a single set of guidelines appropriate for all people with diabetes who wish to exercise, and the best advice is to encourage diabetics to document for themselves what works and what does not work Wallberg-Henriksson, All adjustments of insulin dose prior to exercise must be made relative to carbohydrate ingestion, as will be discussed later.
belgacar.com/components/gsm-espion/pirater-iphone-6-message.php The person with Type 1 DM can become quite proficient in simulating an exercise-induced decline in circulating insulin by decreasing the amount of insulin injected or infused before exercise begins. Avoiding hypoglycemia or hyperglycemia can also be achieved by increasing or decreasing, respectively, the amount of carbohydrate ingested before planned exercise.
Such adjustments in carbohydrate intake are the only alternative for unplanned exercise when the amount of circulating insulin is set by the prior injection or pump infusion rate. This point has special meaning for children because their daily physical activities are often spontaneous.
There has been a recent surge of new data on the subject of exercise and sport in type I diabetes, as well as great interest from the multidisciplinary healthcare. Type 1 Diabetes: Clinical Management of the Athlete: Medicine & Health Science Books @ townrecmocoma.tk
Currently, we know very little about the metabolic adjustments to exercise in children with diabetes Campaigne et al. Children with diabetes should be encouraged to participate unstructured physical activity and in organized sports, and the recommendations in this article can serve as beginning guides for glucose management for both children and adults. Parents, friends, coaches, athletic trainers, sports nutritionists, and sports team members should know the typical signs of hypo and hyperglycemia.
Unfortunately, many of theses signs and symptoms are similar to typical responses to acute exercise in nondiabetic populations. Sweating, pounding heart, shaking, hunger, confusion, drowsiness, difficulty with speech, incoordination, nausea, and headache. In children, irritability and temper tantrums are also symptoms of hypoglycemia.
Typical symptoms of hyperglycemia are less standard than for hypoglycemia. During an acute episode of hyperglycemia, the person can experience restlessness or nervousness. Longer-term hyperglycemia leads to thirst, fatigue, muscle cramps, blurred vision, nausea, drowsiness, and abdominal pain.
The guidelines and principles provided by the American Diabetes Association and other organizations are primarily based on literature specific to endurance aerobic exercise. In general, people with Type 2 DM who perform chronic resistance exercise gain the same metabolic and muscle hypertrophy benefits as do nondiabetics. It is quite disheartening, however, that only three studies Durak et al. This is a major shortcoming because there is some indication that people with Type 1 DM have higher systolic and diastolic blood pressures during bicycle and handgrip exercise compared to nondiabetic control subjects Nazar et al.
Heavy exercise of all types, but particularly resistance exercise, increases arterial pressure to very high levels in people without diabetes. Such high pressures could damage the blood vessels in the eyes of those with diabetes. Therefore, until resistance exercise is proven harmless, the person with diabetes who has preexisting retinal damage should avoid this type of exercise.
It must be realized, however, that no published data exist demonstrating that resistance exercise of any intensity causes damage to blood vessels in the eyes or elsewhere. People with diabetic autonomic neuropathies have difficulty controlling blood pressure, cardiac output, and distribution of blood flow. Each of these could compromise the ability to exercise, especially when such exercise is strenuous.
Those seeking practical advice on this topic should refer to an article published by Hornsby In summary, the benefits of resistance exercise for people with Type 1 DM are not yet established. One might speculate that the benefits of a correctly designed program of resistance exercise would far exceed the risks to adequately screened people with Type 1 DM. As far as body weight and composition are concerned, the benefits of participation in regular physical activity are not entirely the same for those with Type 2 DM and those with Type 1 DM.
As one example, there is a strong tendency, fostered by a genetic predisposition, for people with Type 2 DM—but not Type 1 DM—to become obese. One potential positive outcome of regular exercise is that the extra energy expended during and after exercise can help people with Type 2 DM gain control over excessive weight gain. However, weight loss due to exercise alone is usually not substantial, and exercise is more effective for this outcome when coupled with a reduced-calorie diet. Because insulin is needed for the maintenance of muscle mass, people with Type 1 DM may increase their relative accumulation of body fat while total body weight remains constant.
Table 1 lists adaptations to exercise training for Type 2 DM. The important message from Table 1 is that a program of regular physical activity can reverse many of the defects in metabolism of both glucose and fat that occur in people with Type 2 DM.
Unfortunately, because there is a lack of similar specific information on adaptations to exercise training for those with Type 1DM, a similar table for Type 1 DM cannot be constructed. However, it is known that people with Type 1 DM typically live longer if they participate in regular physical activity as a part of their lifestyles Moy et al.
Exercise and Hemoglobin A1c. Hemoglobin A1c HbA1C is used as an index of long-term blood glucose control, i. The lower the value for HbA1c, the better. The fact that HbA1c is reduced by chronic exercise in people with Type2 DM is important because this means that long-term glucose control has been realized and that with "better" control comes reduced risks for complications.
Unfortunately, the same cannot be said for Type 1 DM. This finding could, however, be a function of limitations in the literature. As one example, many studies showing no change in HbA1c used training protocols that lasted only 1—2 months, but changes in HbA1c do not stabilize at lower levels until at least 80 days after normalization of plasma glucose concentrations caused by insulin treatment.
Moreover, other studies Huttunen et al. Another difficulty in interpretation of the previous literature on the effects of exercise on glucose control in Type 1DM is the dearth of information about the duration of diabetes affliction in the subjects studied. One might speculate that people who have had diabetes for decades may be less responsive to exercise treatments when compared to newly diagnosed individuals.
Psychological benefits of regular exercise are well established for people without diabetes. Such benefits in all probability also occur in people with diabetes, but very few studies have addressed this question. It is possible that the added vigilance in glucose monitoring required for safe exercise could act has a positive reinforcement for people with diabetes to better monitor their blood glucose levels.
Positive alterations in mood or psychological state such as anxiety reduction, increase in vigor, and improved sense of self-worth would obviously be helpful for diabetic patients in "handling" their disease and could also have a positive impact on athletic performance. Athletes with Type I DM who have achieved superior levels of performance have established patterns of carbohydrate feedings and insulinization that work for them. It is clear that individualized trial-and-error with manipulations of diet and insulin administration must occur if such an athlete is to establish reliable glucose control.
The attention of the public is usually drawn to athletes who have succeeded in spite of Type 1 DM, perhaps because we better appreciate their having overcome a lifelong affliction with the disease, in contrast to athletes with Type 2 DM, whose disease typically is manifested in adulthood. In fact, it is unclear how many top athletes have Type 2 DM, perhaps because extensive regular exercise ameliorates insulin resistance to such a great extent that the budding athlete with latent or prior Type 2 DM simply overcomes the disease to the point that it is not apparent.
While purely speculation at this time, it is conceivable that the accomplished athlete with persistent Type 2 DM is a rare find.
J Biol Chem. Australia: Human Kinetics; Egan B, Zierath JR. All titles and abstracts of papers identified by the searches were assessed for inclusion by one reviewer. Go to Amazon. J Acad Nutr Diet. Tim has never let his diagnosis keep him from pursing his goal of playing high school football.
For the most part, previous studies on the metabolic response to exercise in diabetic subjects used exercise protocols that did not reflect sports conditions. Most sports require short periods of very high intensity effort, and most of what we know about exercise metabolism in diabetes is based on research that employed prolonged, moderate and constant-intensity exercise.
Thus, for people with diabetes, the metabolic demands of, and acute responses to, participation in most sports are largely unknown Peirce, Another major gap in our knowledge is a lack of understanding of how diabetes affects recovery from athletic contests. Our personal observations suggest that diabetic university-level athletes in football, swimming, and track may not recover as rapidly as their nondiabetic teammates.