HIIT's påverkan på insulinkänslighet

[Officer]

Eftersom Grub jämt snackar om HIIT's positiva påverkan på insulinkänsligheten, så tänkte jag fråga lite..
Hur pass bättre blir insulinkänsligheten av 10 minuters intervallkondis efter ett pass? Jag menar, finns det några dokumenterade rapporter på procentuella skillnader eller så? Kanske lite långsökt.
Om man kör HIIT 2-3 gånger i veckan, så borde man ju kunna käka ganska mkt skrovmål, då insulinkänsligheten borde vara så pass bra?

Eller?


EDIT: Blev kanske fel forum.. HIIT är ju träning, och dess följd påverkar ju frågan om kost.. hmm ni får flytta den om ni vill.

[King Grub]

J Cardiovasc Risk. 1995 Aug;2(4):303-9.

Influence of exercise on insulin sensitivity.

Henriksson J.

Karolinska Institute, Department of Physiology and Pharmacology, Stockholm, Sweden.

An important determinant of insulin sensitivity in humans, the insulin-induced glucose uptake in skeletal muscle (directed into glycogen synthesis), has been found to be markedly enhanced in endurance-trained individuals compared with sedentary controls. This enhanced insulin action is accompanied by a decreased insulin response during an oral glucose load. Available evidence indicates that the enhanced insulin action is not a genuine training effect, but merely a lasting effect of the previous exercise session(s). In the young, insulin sensitivity increases with a single exercise session, but the increase may appear only after several training sessions in middle-aged or older individuals. The effect disappears after 3-6 days. The exercise-induced reduction in muscle glycogen is an important factor underlying the increased insulin sensitivity in the period after exercise. There are reports that endurance and strength training enhances whole-body insulin sensitivity to a similar extent, and available evidence suggests that, provided total energy expenditure is held constant, low-intensity and high-intensity exercise are equally effective in promoting insulin sensitivity. Differences in sex steroids may explain the observation of a markedly higher insulin sensitivity in women than in men. Adaptations, which might underlie the increased insulin sensitivity in trained individuals, include increases in levels of the glucose transporter protein GLUT-4 and in muscle glycogen synthase activity, a decrease in the serum triglyceride concentration and, possibly, an increase in the muscle capillary network.

[King Grub]

J Appl Physiol. 2002 Aug;93(2):788-96.

Invited review: Effects of acute exercise and exercise training on insulin resistance.

Henriksen EJ.

Muscle Metabolism Laboratory, Department of Physiology, University of Arizona College of Medicine, Tucson, Arizona 85721-0093, USA.

Insulin resistance of skeletal muscle glucose transport is a key defect in the development of impaired glucose tolerance and Type 2 diabetes. It is well established that both an acute bout of exercise and chronic endurance exercise training can have beneficial effects on insulin action in insulin-resistant states. This review summarizes the present state of knowledge regarding these effects in the obese Zucker rat, a widely used rodent model of obesity-associated insulin resistance, and in insulin-resistant humans with impaired glucose tolerance or Type 2 diabetes. A single bout of prolonged aerobic exercise (30-60 min at approximately 60-70% of maximal oxygen consumption) can significantly lower plasma glucose levels, owing to normal contraction-induced stimulation of GLUT-4 glucose transporter translocation and glucose transport activity in insulin-resistant skeletal muscle. However, little is currently known about the effects of acute exercise on muscle insulin signaling in the postexercise state in insulin-resistant individuals. A well-established adaptive response to exercise training in conditions of insulin resistance is improved glucose tolerance and enhanced skeletal muscle insulin sensitivity of glucose transport. This training-induced enhancement of insulin action is associated with upregulation of specific components of the glucose transport system in insulin-resistant muscle and includes increased protein expression of GLUT-4 and insulin receptor substrate-1. It is clear that further investigations are needed to further elucidate the specific molecular mechanisms underlying the beneficial effects of acute exercise and exercise training on the glucose transport system in insulin-resistant mammalian skeletal muscle.

[King Grub]

Int J Sports Med. 2000 Jan;21(1):1-12.

Exercise and insulin sensitivity: a review.

Borghouts LB, Keizer HA.

Department of Movement Sciences, Maastricht University, The Netherlands.

Physical activity has a beneficial effect on insulin sensitivity in normal as well as insulin resistant populations. A distinction should be made between the acute effects of exercise and genuine training effects. Up to two hours after exercise, glucose uptake is in part elevated due to insulin independent mechanisms, probably involving a contraction-induced increase in the amount of GLUT4 associated with the plasma membrane and T-tubules. However, a single bout of exercise can increase insulin sensitivity for at least 16 h post exercise in healthy as well as NIDDM subjects. Recent studies have accordingly shown that acute exercise also enhances insulin stimulated GLUT4 translocation. Increases in muscle GLUT4 protein content contribute to this effect, and in addition it has been hypothesized that the depletion of muscle glycogen stores with exercise plays a role herein. Physical training potentiates the effect of exercise on insulin sensitivity through multiple adaptations in glucose transport and metabolism. In addition, training may elicit favourable changes in lipid metabolism and can bring about improvements in the regulation of hepatic glucose output, which is especially relevant to NIDDM. It is concluded that physical training can be considered to play an important, if not essential role in the treatment and prevention of insulin insensitivity.

[King Grub]

Annu Rev Med. 1998;49:235-61.

Exercise, glucose transport, and insulin sensitivity.

Goodyear LJ, Kahn BB.

Research Division, Joslin Diabetes Center, Brigham and Women's Hospital, Boston, Massachusetts, USA.

Physical exercise can be an important adjunct in the treatment of both non-insulin-dependent diabetes mellitus and insulin-dependent diabetes mellitus. Over the past several years, considerable progress has been made in understanding the molecular basis for these clinically important effects of physical exercise. Similarly to insulin, a single bout of exercise increases the rate of glucose uptake into the contracting skeletal muscles, a process that is regulated by the translocation of GLUT4 glucose transporters to the plasma membrane and transverse tubules. Exercise and insulin utilize different signaling pathways, both of which lead to the activation of glucose transport, which perhaps explains why humans with insulin resistance can increase muscle glucose transport in response to an acute bout of exercise. Exercise training in humans results in numerous beneficial adaptations in skeletal muscles, including an increase in GLUT4 expression. The increase in muscle GLUT4 in trained individuals contributes to an increase in the responsiveness of muscle glucose uptake to insulin, although not all studies show that exercise training in patients with diabetes improves overall glucose control. However, there is now extensive epidemiological evidence demonstrating that long-term regular physical exercise can significantly reduce the risk of developing non-insulin-dependent diabetes mellitus.

[Officer]

Tusen tack!