Search Results

You are looking at 31 - 40 of 282 items for :

Clear All
Restricted access

Ezzedine Bouhlel, Myriam Denguezli, Monia Zaouali, Zouhair Tabka and Roy J. Shephard

Purpose:

To evaluate the effect of Ramadan fasting on parameters of insulin resistance in trained athletes at rest and after aerobic exercise.

Methods:

Nine male rugby players (age 19 ± 2 yr, height 1.78 ± 0.74 m) were tested 3 times: 1 week before observance of Ramadan (C), at the end of the first week (R1), and during the fourth week (R2). They performed a progressive cycle-ergometer test at each visit. Data collected at rest and at the end of aerobic exercise included simple anthropometry (body mass, body-mass index, body fat, fat-free mass), biochemical parameters (serum glucose, cholesterol, HDL cholesterol, triglycerides, creatinine, and serum proteins), and selected hormone concentrations (plasma insulin, leptin, and adiponectin).

Results:

Ramadan fasting was associated with a reduction of body mass and body fat (R2 vs. C, p < .01) without significant change in leptin or adiponectin levels.

Conclusion:

Lipolysis might have occurred because of increased plasma triglycerides and HDL cholesterol concentrations.

Restricted access

Leyre Gravina, Frankie F. Brown, Lee Alexander, James Dick, Gordon Bell, Oliver C. Witard and Stuart D.R. Galloway

Omega-3 fatty acid (n-3 FA) supplementation could promote adaptation to soccer-specific training. We examined the impact of a 4-week period of n-3 FA supplementation during training on adaptations in 1RM knee extensor strength, 20-m sprint speed, vertical jump power, and anaerobic endurance capacity (Yo-Yo test) in competitive soccer players. Twenty six soccer players were randomly assigned to one of two groups: n-3 FA supplementation (n-3 FA; n = 13) or placebo (n = 13). Both groups performed two experimental trial days. Assessments of physical function and respiratory function were conducted pre (PRE) and post (POST) supplementation. Training session intensity, competitive games and nutritional intake were monitored during the 4-week period. No differences were observed in respiratory measurements (FEV1, FVC) between groups. No main effect of treatment was observed for 1RM knee extensor strength, explosive leg power, or 20 m sprint performance, but strength improved as a result of the training period in both groups (p < .05). Yo-Yo test distance improved with training in the n-3 FA group only (p < .01). The mean difference (95% CI) in Yo-Yo test distance completed from PRE to POST was 203 (66–340) m for n-3 FA, and 62 (-94–217) m for placebo, with a moderate effect size (Cohen’s d of 0.52). We conclude that 4 weeks of n-3 FA supplementation does not improve strength, power or speed assessments in competitive soccer players. However, the increase in anaerobic endurance capacity evident only in the n-3 FA treatment group suggests an interaction that requires further study.

Restricted access

Vinicius Coneglian Santos, Adriana Cristina Levada-Pires, Sâmia Rocha Alves, Tânia Cristina Pithon-Curi, Rui Curi and Maria Fernanda Cury-Boaventura

Purpose:

To investigate the effects of docosahexaenoic-(DHA)-rich fish oil (FO) supplementation on lymphocyte function before and after a marathon race.

Methods:

Twenty-one athletes participated in this study. Eight marathon runners were supplemented with 3 g of FO daily for 60 d (FO group), and 13 athletes were not supplemented (C group). The following measures of lymphocytes were taken before and after the marathon: cell proliferation, cytokine production (IL-2, IL-10, TNF-α, and IL-4), and signs of cell death.

Results:

In the C group, the marathon had no effect on lymphocyte proliferation, DNA fragmentation, or mitochondrial membrane polarization; however, the marathon increased phosphatidylserine externalization (by 2.5-fold), induced a loss of plasma membrane integrity (by 20%), and decreased IL-2, TNF-α, and IL-10 production (by 55%, 95%, and 50%, respectively). FO supplementation did not prevent lymphocyte death induced by the marathon, as indicated by cell viability, DNA fragmentation, and phosphatidylserine externalization. However, FO supplementation increased lymphocyte proliferation before and after the marathon, and before the race, FO supplementation decreased IL-2, TNF-α, and IL-10 production in concanavalin-A-stimulated lymphocytes (by 55%, 95%, and 58%, respectively) compared with cells from the C group. The production of cytokines was not altered before or after the race in the FO group.

Conclusions:

DHA-rich FO supplementation increased lymphocyte proliferation and prevented a decrease in cytokine production, but it did not prevent lymphocyte death induced by participation in the marathon. Overall, DHA rich-FO supplementation has beneficial effects in preventing some of the changes in lymphocyte function induced by marathon participation.

Restricted access

Martin Tan, Rachel Chan Moy Fat, Yati N. Boutcher and Stephen H. Boutcher

High-intensity intermittent exercise (HIIE) such as the 30-s Wingate test attenuates postprandial triacylglycerol (TG), however, the ability of shorter versions of HIIE to reduce postprandial TG is undetermined. Thus, the effect of 8-s sprinting bouts of HIIE on blood TG levels of 12 females after consumption of a high-fat meal (HFM) was examined. Twelve young, sedentary women (BMI 25.1 ± 2.3 kg/m2; age 21.3 ± 2.1 years) completed a maximal oxygen uptake test and then on different days underwent either an exercise or a no-exercise postprandial TG condition. Both conditions involved consuming a HFM after a 12-hr fast. The HFM, in milkshake form provided 4170 kJ (993 Kcal) of energy and 98 g fat. Order was counter-balanced. In the exercise condition participants completed 20-min of HIIE cycling consisting of repeated bouts of 8 s sprint cycling (100–115 rpm) and 12 s of active rest (easy pedaling) 14 hr before consuming the HFM. Blood samples were collected hourly after the HFM for 4 hr. Total postprandial TG was 13% lower, p = .004, in the exercise (5.84 ± 1.08 mmol L−1 4 h−1) compared with the no-exercise condition (6.71 ± 1.63 mmol L−1 4 h−1). In conclusion, HIIE significantly attenuated postprandial TG in sedentary young women.

Restricted access

Bettina Mittendorfer and Samuel Klein

Endurance exercise increases the use of endogenous fuels to provide energy for working muscles. Elderly subjects oxidize more glucose and less fat during moderate intensity exercise. This shift in substrate use is presumably caused by age-related changes in skeletal muscle, including decreased skeletal muscle respiratory capacity, because adipose tissue lipolysis and plasma fatty acid availability are not rate limiting. Endurance training in elderly subjects increases muscle respiratory capacity, decreases glucose production and oxidation, and increases fat oxidation thereby correcting or compensating for the alterations in substrate oxidation associated with aging.

Restricted access

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.

Restricted access

YoonMyung Kim

addition, limited evidence also demonstrates a significant relationship between intermuscular adipose tissue (IMAT) or intramyocellular lipid (IMCL) content within skeletal muscle and obesity-related health abnormalities in children and adolescents ( 40 , 64 ). These results clearly suggest that depot

Restricted access

Lee Smith, Brendon Stubbs, L. Hu, Nicola Veronese, Davy Vancampfort, Genevieve Williams, Domenico Vicinanza, Sarah E. Jackson, Li Ying, Guillermo F. López-Sánchez and Lin Yang

. However, the review identified just one study investigating the association between active transport and lipid levels and showing an increase in high-density lipoprotein cholesterol (HDL-C) but no changes in serum total cholesterol or triglyceride concentrations. 14 Further research is required to

Restricted access

Stephanie L. Stockwell, Lindsey R. Smith, Hannah M. Weaver, Daniella J. Hankins and Daniel P. Bailey

Cardiometabolic disease is an uncommon occurrence or cause of death in children. However, cardiometabolic risk markers such as obesity, high blood pressure, adverse lipid profile, and impaired glucose levels can begin to develop in childhood, increasing the likelihood of cardiometabolic disease in

Restricted access

Thiago Correa Porto Gonçalves, Atila Alexandre Trapé, Jhennyfer Aline Lima Rodrigues, Simone Sakagute Tavares and Carlos Roberto Bueno Junior

, Carvalho, Soares, Marques, & Mota, 2009 ; Neves et al., 2016 ). Both aerobic and muscle strength exercises are recommended for older adults regarding evidence of benefits to the lipid profile ( Chodzko-Zajko et al., 2009 ), upper and lower body strength, and agility ( Kang, Hwang, Klein, Kim, & Kim, 2015