Improved insulin action in muscle, liver, and adipose tissue in physically trained human subjects

Rodnick, Kenneth J.; Haskell, W. L.; Swislocki, Arthur L; Foley, James E.; Reaven, Gerald M.

doi:10.1152/ajpendo.1987.253.5.e489

Cited by 70 publications

(64 citation statements)

References 26 publications

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“…Although ingested carbohydrate content was larger than in the previous studies, fat metabolism during exercise showed no difference among conditions, which may be influenced by the high capacity for insulin sensitivity in the subjects. Energy metabolism during exercise in athletes and diabetic patients cannot be easily compared because insulin sensitivity is higher in athletes compared with sedentary subjects and such patients, which may have led to the difference between the present study and a previous study (29). CHO absorbed from the intestines into blood after a meal is rapidly taken into muscle cells in athletes, which may have resulted in the phenomenon energy metabolism during exercise did not differ regardless of elapsed time after meal, because compared to the level shown immediately before exercise in the no-meal trial, the serum insulin level was elevated over a shorter interval in the meal trials after the exercise.…”

Section: Discussioncontrasting

confidence: 68%

The Effect of the Timing of Meal Intake on Energy Metabolism during Moderate Exercise

Sasaki

Nakae²,

Ebine

et al. 2014

J Nutr Sci Vitaminol

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During exercise, the energy consumed in muscle tissue is mainly supplied by carbohydrates (CHO) and fats. In regard to health promotion and athletic sports, it is important to regulate the metabolism of these two substrates. Fats are supplied by meals, and also by adipose tissues, but CHO must be acquired from meals before exercise because little is stored as glycogen in the liver or muscle tissue. Previous studies have been conducted on the ergogenic effects of CHO feeding before exercise (1-10). It was reported that CHO solution (such as glucose and maltodextrin) feeding before exercise can improve exercise performance through enhanced endurance exercise capacity (2,4,5,10). Moreover, it was also reported that CHO mixed meal feeding before exercise can improve endurance exercise capacity (7,9,11).The intake of CHO elevates the secretion of insulin from the pancreas into the blood. Glucose and insulin in plasma reach a peak approximately 30 min after the ingestion of CHO and thereafter gradually decrease to the basal level. Insulin facilitates glucose uptake into skeletal muscle cells via the translocation of glucose transporter 4 (GLUT4) and then increases CHO oxidation. On the other hand, insulin prevents fat oxidation in muscle tissue by inhibition of lipoprotein lipase activity (12). Hyperinsulinemia tends to supply energy with a predominance of CHO over fats as the energy source in the initial period during exercise (7). Previous studies have shown, by examining timing of carbohydrate intake before exercise, that a shorter time from intake to exercise increases blood glucose and insulin levels at the start of exercise and these factors gradually decrease after the start of exercise (9, 10). Moreover, Chryssanthopoulos et al. (5) have reported that glucose intake at 30 min before exercise causes a rapid reduction of blood glucose after the beginning of exercise. On the other hand, Coyle et al. (13) have shown that carbohydrate utilization during exercise is higher under the condition of meal intake at 4 h before exercise compared with the fasting condition. Therefore, regardless of the timing of carbohydrate intake, it is likely that carbohydrate intake before exercise promotes its utilization as a major energy Life and Environmental Sciences, Kyoto Prefectural University, 1-5 Hangi-cho, Shimogamo, Sakyo-ku, Kyoto, Kyoto 606-8522, Japan (Received June 5, 2013) Summary Although the intake of carbohydrates is important for the supplementation of energy substrate utilized during exercise, fat oxidation is possibly prevented by an elevation of insulin, and whether or not the timing of the intake of meals affects energy metabolism during exercise has not been clarified. The purpose of this study was to investigate the effect of the timing of the intake of meals taken at different times before exercise on the carbohydrate and fat metabolism during aerobic exercise. The subjects were eight young trained athletes who performed cycling exercise at the lactate threshold (LT) intensity for 60 min. They performe...

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Section: Discussioncontrasting

confidence: 68%

The Effect of the Timing of Meal Intake on Energy Metabolism during Moderate Exercise

Sasaki

Nakae²,

Ebine

et al. 2014

J Nutr Sci Vitaminol

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“…34 Moreover, it is well known that endurance training improves insulin sensitivity in young adults as well as in elderly people 35,36 and improved insulin action has been associated with a higher glucose uptake at the muscle level. 35 Moreover, under hyperinsulinaemic hyperglycaemic conditions, insulin andaor glucose have been shown to inhibit fat oxidation by controlling the rate of long chain FFA entrance into the mitochondria. 37 This could be associated with the stimulant effect of insulin and glucose on the production of malonyl-CoA, a powerful inhibitor of the FFA carrier into the mitochondria.…”

Section: Discussionmentioning

confidence: 99%

Time-course effects of endurance training on fat oxidation in sedentary elderly people

et al. 1999

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OBJECTIVE: To investigate alterations in whole body fat oxidation after 7 and 14 weeks of progressive endurance training in sedentary elderly subjects. DESIGN: Longitudinal, 14 weeks of progressive endurance training on a cycle ergometer (3 training sessions per week). Full sets of measurements were performed before, and after 7 and 14 weeks of training. SUBJECTS: 13 healthy sedentary subjects (5 men, 8 women) (age 62.8 AE 2.3 y). MEASUREMENTS: 24 h indirect calorimetric measurements under standardised conditions: light-activity programme, ®xed food composition, neutral daily energy balance. Body composition (by isotope dilution and skinfold thicknesses). Maximal oxygen consumption. RESULTS: Loss of 0.7 kg fat mass in the ®rst 7 weeks of training and a further 2.4 kg of fat in the second 7 weeks. There was a transient increase in sleeping fat oxidation after 7 weeks of training ( 26.1%), associated with transient increase in daily fat oxidation ( AE 11.9%), but fat oxidation then returned to baseline values in the second 7 weeks. There was a correlation between within-subject changes in sleeping fat oxidation after 7 weeks of training and variations in FFM (r 0.62, P 0.02) and maximal oxygen consumption (r À0.56, P`0.05). CONCLUSION: In sedentary elderly subjects, progressive endurance training was associated with a transient increase in sleeping fat oxidation and daily fat oxidation. In free-living conditions, possible changes in daily fat oxidation may have induced a negative fat balance, as judged by fat mass loss.

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“…The inclusion of an arm ergometer training programme, as part of a comprehensive primary rehabilitation programme in recently injured tetraplegic patients, has not previously been studied. Since there is a positive correlation between peak oxygen uptake and whole body glucose uptake in healthy individuals, 17,18 we speculated that endurance training in tetraplegic subjects would similarly lead to increased peak oxygen uptake, and improve whole body glucose disposal.…”

Section: Introductionmentioning

confidence: 99%

Improved work capacity but unchanged peak oxygen uptake during primary rehabilitation in tetraplegic patients

Hjeltnes

Wallberg-Henriksson

1998

Spinal Cord

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Individuals with cervical spinal cord lesions are characterised by markedly decreased aerobic capacity, accompanied by increased risk of developing cardiovascular disease. The aim of this study was to evaluate the eects of a primary rehabilitation programme that included three sessions of arm cycling per week on the endurance capacity in 10 male tetraplegic subjects (injury level C6-C8; eight ASIA-A and two ASIA-B). Peak oxygen uptake (peak VO 2 ) was measured three times (at T1 & 99+10 days after injury, T2 & 2 months after T1, and at T3 & 2 months after T2). Ten paraplegic patients admitted to the hospital for primary rehabilitation served as controls. In the tetraplegic patients, mean peak load increased (22+2, 32+5, and 32+7 watt, at T1, T2 and T3 respectively) (P50.01), while mean peak VO 2 did not change during the study (0.78+0.07, 0.86+0.08, and 0.81+0.06 16min 71 , at T1, T2 and T3, respectively) (ns). In contrast peak VO 2 was signi®cantly higher in the paraplegic control group (1.37+0.08, 1.64+0.10 and 1.75+0.08 16min 71 , respectively) (P50.001), and increased signi®cantly during the study period (P50.001). Mean heart rate (HR) and mean stroke volume (SV), measured at corresponding submaximal work loads during the study did not change signi®cantly in the tetraplegic patients. Mean systolic blood pressure (SBP), recorded immediately after peak arm exercise was low at all three tests (93+8, 89+6 and 84+6 mmHg) in the tetraplegic group. However, both muscle strength and`activities of daily life' index improved signi®cantly during the study period. Our results suggest that functional improvement in tetraplegic patients is not necessarily followed by aerobic metabolic improvement. We conclude that more time should be spent on arm endurance training, or training methods which activate larger muscle groups and/or increases blood pressure.

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Improved insulin action in muscle, liver, and adipose tissue in physically trained human subjects

Cited by 70 publications

References 26 publications

The Effect of the Timing of Meal Intake on Energy Metabolism during Moderate Exercise

The Effect of the Timing of Meal Intake on Energy Metabolism during Moderate Exercise

Time-course effects of endurance training on fat oxidation in sedentary elderly people

Improved work capacity but unchanged peak oxygen uptake during primary rehabilitation in tetraplegic patients

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