Diminished insulin response in highly trained athletes

Lohmann, Dieter; Liebold, F; Heilmann, Wolf-Rüdiger; Senger, H; Pohl, A

doi:10.1016/0026-0495(78)90017-3

Cited by 140 publications

(62 citation statements)

References 10 publications

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“…Discordance between changes in muscle GLUT-4 mRNA and protein content has been described in fasted rats (57), which are characterized by hypoinsulinemia. Lower than normal insulin concentrations have also been reported in insulin-sensitive, well-trained athletes both in the basal state and in response to glucose challenge (33,39). In the current study, serum basal insulin concentrations in the athletes were slightly, although not significantly, below normal.…”

Section: Discussionmentioning

confidence: 98%

Mechanism of enhanced insulin sensitivity in athletes. Increased blood flow, muscle glucose transport protein (GLUT-4) concentration, and glycogen synthase activity.

Ebeling¹,

Bourey²,

Korányi³

et al. 1993

J. Clin. Invest.

221

165

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IntroductionWe examined the mechanisms of enhanced insulin sensitivity in 9 male healthy athletes (age, 25±1 yr; maximal aerobic power [V O2maxJ, 57.6±1.0 ml/kg per min) as compared with 10 sedentary control subjects (age, 28±2 yr; V02max, 44.1±2.3 ml/kg per min). In the athletes, whole body glucose disposal (240-min insulin clamp) was 32% (P < 0.01 ) and nonoxidative glucose disposal (indirect calorimetry) was 62% higher (P < 0.01 ) than in the controls. Muscle glycogen content increased by 39% in the athletes (P < 0.05) but did not change in the controls during insulin clamp. VO2max correlated with whole body (r = 0.60, P < 0.01) and nonoxidative glucose disposal (r = 0.64, P < 0.001). In the athletes forearm blood flow was 64% greater (P < 0.05) than in the controls, whereas their muscle capillary density was normal. Basal blood flow was related to VO2max (r = 0.63, P < 0.05) and glucose disposal during insulin infusion (r = 0.65, P < 0.05). The forearm glucose uptake in the athletes was increased by 3.3-fold (P < 0.01) in the basal state and by 73% (P < 0.05) during insulin infusion. Muscle glucose transport protein (GLUT4) concentration was 93% greater in the athletes than controls (P < 0.01 ) and it was related to VO2max (r = 0.61, P < 0.01 ) and to whole body glucose disposal (r = 0.60, P < 0.01). Muscle glycogen synthase activity was 33% greater in the athletes than in the controls (P < 0.05), and the basal glycogen synthase fractional activity was closely related to blood flow (r = 0.88, P < 0.001).In conclusion: (a) athletes are characterized by enhanced muscle blood flow and glucose uptake. (b) The cellular mechanisms of glucose uptake are increased GLUT4 protein content, glycogen synthase activity, and glucose storage as glycogen. (c) A close correlation between glycogen synthase fractional activity and blood flow suggests that they are causally related in promoting glucose disposal. (J.

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Section: Discussionmentioning

confidence: 98%

Mechanism of enhanced insulin sensitivity in athletes. Increased blood flow, muscle glucose transport protein (GLUT-4) concentration, and glycogen synthase activity.

Ebeling¹,

Bourey²,

Korányi³

et al. 1993

J. Clin. Invest.

221

165

View full text Add to dashboard Cite

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“…Several studies have demonstrated enhanced glucose tolerance in endurance athletes and an apparent increase of insulin sensitivity during physical training in normal and diabetic subjects [7,8,. Whether the improvements in glucose tolerance were the result of the summed effects of individual exercise bouts or of the trained state has not been addressed by these studies.…”

Section: Discussionmentioning

confidence: 99%

“…Physical training is believed to improve a number of the factors which may predispose to these complications, including abnormalities in plasma lipids and lipoproteins [3][4][5], hyperglycaemia and hyperinsulinaemia [6][7][8][9][10]; for this reason it has been recommended in the treatment of Type 2 diabetes [11,12]. Despite this, information concerning the effectiveness of physical training in Type 2 diabetes is limited and it is unclear whether observed benefits are due to acute effects of exercise or to improved physical fitness.…”

mentioning

confidence: 99%

Studies on the mechanism of improved glucose control during regular exercise in Type 2 (non-insulin-dependent) diabetes

et al. 1984

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Summary. The effects of 6 weeks of thrice weekly training on glycaemic control were assessed in 20 sedentary Type 2 (noninsulin-dependent) diabetic patients and 11 control subjects matched for previous physical activity. Maximal oxygen uptake was lower in the diabetic patients than in control subjects before training (26.2 + 1.1 versus 32.6___ 1.7 ml. kg -1. min -1 ; p < 0.001). Glycosylated haemoglobin levels decreased in the diabetic patients during the training programme (12.2 + 0.5 to 10.7 + 0.4%; p < 0.02). Oral and intravenous glucose tolerance determined 72 h after the last exercise period showed only minimal improvement. Plasma glucose levels were, however, significantly lower at 12 h than 72 h after exercise in eight subjects tested at both time points. These data suggest that an exercise programme can produce a significant decrease in glycosylated haemoglobin levels in Type 2 diabetic males probably due, in great measure, to the cumulative effect of transient improvements in glucose tolerance which follow each individual period of exercise.

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“…Athletes have normal or increased tolerance to oral glucose in conjunction with low basal and glucose-stimulated insulin responses (74), and physical inactivity rapidly results in decreased glucose tolerance (75). Both normal control subjects and patients with type II diabetes have been shown to have a 30-35% increase in insulin-stimulated glucose disposal after physical training when studied by the hyperinsulinemic-euglycemic clamp technique (7,76,77).…”

Section: Exercise In Type II Diabetesmentioning

confidence: 99%

Role and Management of Exercise in Diabetes Mellitus

Horton

1988

Diabetes Care

111

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As more is understood about the physiology of exercise, in both normal and diabetic subjects, its role in the treatment of diabetes is becoming better defined. Whereas people with diabetes may derive many benefits from regular physical exercise, there are also several hazards that make exercise difficult to manage. In type I (insulin-dependent) diabetes, there are risks of hypoglycemia during or after exercise or of worsening metabolic control if insulin deficiency is present. Type II (non-insulin-dependent) diabetic patients treated with sulfonylureas are also at some increased risk of developing hypoglycemia during or after exercise, although this poses less of a problem than with insulin treatment. In individuals treated by diet alone, regulation of blood glucose during exercise is usually not a significant problem and exercise can be used as an adjunct to diet to achieve weight loss and improved insulin sensitivity. When obese type II diabetic patients are treated with very low calorie diets, adequate amounts of carbohydrate must be provided to ensure maintenance of normal muscle glycogen content, particularly if individuals wish to participate in highintensity exercise that places a heavy workload on specific muscle groups. On the other hand, moderateintensity exercise such as vigorous walking can be tolerated by individuals on very low calorie, carbohydrate-restricted diets after an appropriate period of adaptation. A number of strategies can be employed to avoid hypoglycemia in type I diabetic patients, and both type I and II diabetic patients should be examined carefully for long-term complications of their disease, which may be made worse by exercise. These considerations have led many diabetologists to consider exercise beneficial in the management of diabetes for

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Diminished insulin response in highly trained athletes

Cited by 140 publications

References 10 publications

Mechanism of enhanced insulin sensitivity in athletes. Increased blood flow, muscle glucose transport protein (GLUT-4) concentration, and glycogen synthase activity.

Mechanism of enhanced insulin sensitivity in athletes. Increased blood flow, muscle glucose transport protein (GLUT-4) concentration, and glycogen synthase activity.

Studies on the mechanism of improved glucose control during regular exercise in Type 2 (non-insulin-dependent) diabetes

Role and Management of Exercise in Diabetes Mellitus

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