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Hyun-Tae Kim

We investigated the effect of long-term treatment (6 wk) with selenium and vitamin E, in combination with aerobic exercise training, on malondialdehyde (MDA), oxidized low-density lipoprotein (ox-LDL), and glutathione peroxi-dase (GPx) in STZ-induced diabetic rats. The rats were assigned randomly to one of three treatment groups (n = 12 per group): 1) exercise group (EX), 2) selenium/vitamin E/exercise group (SVE), and 3) selenium/vitamin E group (SV). To estimate the acute effect of exercise, a 30-min endurance exercise was used. The MDA concentration was significantly lower in the SVE. The ox-LDL was significantly lower in the SVE and SV. The hepatic concentrations of selenium and vitamin E were significantly higher in the SVE. These results indicate that the increase in MDA is mildly attenuated in rats that were aerobically trained. Moreover, the joint administration of selenium and vitamin E with or without exercise training reduces the levels of ox-LDL.

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Kyu-Jin Lee, Yun-A. Shin, Kyoung-Young Lee, Tae-Won Jun and Wook Song

The purpose of this study was to assess differences in the levels of plasma visfatin among female adolescents and changes in plasma visfatin and insulin resistance in obese female adolescents after 12 wk of aerobic exercise training. Twenty normal-weight female students (body-mass index [BMI] <22.9 kg/m2 and body fat ≤29.9) and 18 obese female students (BMI ≥25 kg/m2 and body fat ≥30%) participated in this study. Eleven obese students were assigned to an exercise group and completed a 12-wk aerobic exercise-training program that included four 40- to 50-min sessions per wk with an energy expenditure of 300–400 kcal/d. Seven obese students were assigned to a control group that received no exercise sessions or dietary restriction. The plasma visfatin levels of obese female adolescents were significantly higher (p < .05) than those of the normal-weight female adolescents. The plasma visfatin levels (294.00 ± 124.74 ng/ml to 185.55 ± 67.30 ng/ml, p < .01) and insulin resistance (p < .05) were significantly reduced after 12 wk of aerobic exercise. The results suggest that aerobic exercise resulting in an energy expenditure of 1,200–1,600 kcal/wk for 12 wk decreases plasma visfatin and insulin resistance in obese female adolescents.

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Loretta DiPietro, Catherine W. Yeckel and James Dziura

Background:

Few studies have compared long-term moderate-intensity aerobic versus light-resistance training on serial improvements in glucose tolerance in older people.

Methods:

Healthy, inactive older (74 ± 5 [SD] years) women (N = 20) were randomized into either a high-volume, moderate-intensity aerobic (ATM, n = 12) or a lower-intensity resistance training (RTL, n = 8) group. Both groups exercised under supervision 4 times per week for 45- to 60-minute sessions over 9 months. Measurements of plasma glucose, insulin, and free fatty acid (FFA) responses to an oral glucose tolerance test (OGTT) were performed at baseline and at 3, 6, and 9 months 48 hours after the last exercise session.

Results:

We observed significant improvements in 2-hour glucose concentrations at 3, 6, and 9 months among women in the RTL (152 ± 42 vs 134 ± 33 vs 134 ± 24 vs 130 ± 27 mg · dL−1; P < .05), but not the ATM (151 ± 25 vs 156 ± 37 vs 152 ± 40 vs 155 ± 39 mg · dL−1) group. These improvements were accompanied by an 18% (P < .07) decrease in basal FFA concentrations in the RTL group, whereas basal and 30-minute FFA concentrations increased (P < .05) after training in the ATM group.

Conclusions:

These findings suggest that the net physiological benefits of exercise might have been blunted in the ATM group, owing to higher circulating levels of FFA, which might have temporarily interfered with insulin action.

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Column-editor : Mark A. Merrick

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Debra M. Vinci

Column-editor : Susan M. Kleiner

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Carolyn C. Jimenez

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Jeanine L. Jones

Column-editor : G. Monique Butcher Mokha

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Roy L.P.G. Jentjens and Asker E. Jeukendrup

Vanadium compounds have been shown to have insulin-like properties in rats and non-insulin-dependent diabetic humans. The purpose of the present study was to examine whether the effects of acute and short-term administration of vanadyl sulphate (VS) on insulin sensitivity also exist in healthy active individuals. Five male and 2 female participants (age: 24.9 ± 1.5 years; height: 176.1 ± 2.9 cm; body mass: 70.1 ± 2.9 kg) underwent 3 oral glucose tolerance tests (OGTT). The first OGTT was performed to obtain a baseline index of insulin sensitivity (ISI). On the night preceding the second OGTT, participants ingested 100 mg of VS, and the acute effects of VS on ISI were examined. For the next 6 days, participants were instructed to ingest 50 mg of VS twice daily, and a final OGTT was performed on day 7 to determine the short-term effects of VS on ISI. No differences were found in fasting plasma glucose and insulin concentrations after VS administration. Furthermore, ISI after 1 day and 7 days of VS administration was not different compared with baseline ISI (4.8±0.1 vs. 4.7±0.1 vs. 4.7 ± 0.1, respectively). These results demonstrate that there are no acute and short-term effects of VS administration on insulin sensitivity in healthy humans.

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Kris Berg, Marchell Cuppett and Michele Helzer-Julin