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Rachel D. Smetanka, C. Patrick Lambert, Robert Murray, Dennis Eddy, Mary Horn and Carl V. Gisolfi

Abdominal cramping, nausea, diarrhea, and GI bleeding are often reported in long-distance runners. This study set out to determine the effects of prolonged (2-4 hrs) exercise and NSAID ingestion on gastric and intestinal permeability during the first 5 hrs following the 1996 Chicago Marathon. Thirty-four healthy volunteers (20 M, 14 F; ages 30-50) completed the race and ingested the test solution (5 g sucrose, 5 g lactulose, 2 g rhamnose, in 40 ml water) within 10-15 min. The urinary excretion ratio of lactulose/rhamnose was used to assess small intestine permeability; sucrose excretion was used to evaluate gastric impairment. There were no significant differences for mean training mileage, postrace rectal temperature, and percent dehydration between runners who ingested NSAIDs and those who did not. In all, 75% of subjects reported aspirin or ibuprofen ingestion before or during the race. Runners who ingested ibuprofen had significant elevations in urinary lactulose excretion and lactulose/rhamnose ratio, whereas those who ingested aspirin or who did not ingest either NSAID had no significant differences in urinary excretion of lactulose, rhamnose, sucrose, or lactulose/rhamnose ratio compared to resting controls. Thirteen of the 26 NSAID users and 4 of the 8 non-users reported GI symptoms. It is concluded that (a) ibuprofen but not aspirin ingestion during prolonged exercise may increase gastrointestinal permeability and lead to GI symptoms, and (b) prolonged exercise alone can produce GI symptoms.

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Hee-Tae Roh, Su-Youn Cho, Hyung-Gi Yoon and Wi-Young So

We investigated the effects of aerobic exercise intensity on oxidative–nitrosative stress, neurotrophic factor expression, and blood–brain barrier (BBB) permeability. Fifteen healthy men performed treadmill running under low-intensity (LI), moderate-intensity (MI), and high-intensity (HI) conditions. Blood samples were collected immediately before exercise (IBE), immediately after exercise (IAE), and 60 min after exercise (60MAE) to examine oxidative–nitrosative stress (reactive oxygen species [ROS]; nitric oxide [NO]), neurotrophic factors (brain-derived neurotrophic factor [BDNF]; nerve growth factor [NGF]), and blood-brain barrier (BBB) permeability (S-100β; neuron-specific enolase). ROS concentration significantly increased IAE and following HI (4.9 ± 1.7 mM) compared with that after LI (2.8 ± 1.4 mM) exercise (p < .05). At 60MAE, ROS concentration was higher following HI (2.5 ± 1.2 mM) than after LI (1.5 ± 0.5 mM) and MI (1.4 ± 0.3 mM) conditions (p < .05). Plasma NO IAE increased significantly after MI and HI exercise (p < .05). Serum BDNF, NGF, and S-100b levels were significantly higher IAE following MI and HI exercise (p < .05). BDNF and S-100b were higher IAE following MI (29.6 ± 3.4 ng/mL and 87.1 ± 22.8 ng/L, respectively) and HI (31.4 ± 3.8 ng/mL and 100.6 ± 21.2 ng/L, respectively) than following LI (26.5 ± 3.0 ng/mL and 64.8 ± 19.2 ng/L, respectively) exercise (p < .05). 60MAE, S-100b was higher following HI (71.1 ± 14.5 ng/L) than LI (56.2 ± 14.7 ng/L) exercise (p < .05). NSE levels were not significantly different among all intensity conditions and time points (p > .05). Moderate- and/or high-intensity exercise may induce higher oxidative-nitrosative stress than may low-intensity exercise, which can increase peripheral neurotrophic factor levels by increasing BBB permeability.

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Samantha K. Gill, Dean M. Allerton, Paula Ansley-Robson, Krystal Hemmings, Martin Cox and Ricardo J.S. Costa

The study aimed to determine if short-term high dose probiotic supplementation containing Lactobacillus casei (L.casei) attenuates the commonly reported exertional-heat stress (EHS) induced endotoxinaemia and cytokinaemia. Eight endurance trained male volunteers (mean± SD: age 26 ± 6 y, nude body mass 70.2 ± 8.8 kg, height 1.75 ± 0.05 m, VO2max 59 ± 5 ml·kg-1·min-1) completed a blinded randomized cross-over design, whereby oral ingestion of a commercially available probiotic beverage containing L.casei (volume equivalent for ×1011 colony forming units·day-1) (PRO) or placebo (PLA) was consumed for 7 consecutive days before exposure to EHS, which comprised of 2h running exercise at 60% VO2max in hot ambient conditions (34.0 °C and 32% RH). Blood samples were collected at baseline (7 days before EHS), pre-EHS, post-EHS (1 hr, 2 hr, 4 hr, and at 24 hr). Plasma samples were analyzed for gram-negative bacterial endotoxin, cytokine profile (IL-6, IL-1β, TNF-α, IFN-γ, IL-8, and IL-10) and plasma osmolality. Plasma osmolality did not differ between trials. Seven days of L.casei supplementation did not show significant changes in resting circulatory endotoxin concentration or plasma cytokine profile compared with PLA. A main effect of time was observed for IL-6, TNF-α, IL-10 and IL-8; whereby levels increased in response to EHS (p < .05). Relative to pre-EHS concentrations, higher plasma concentrations of endotoxin (p = .05), and a trend for higher plasma TNF-α concentration (p = .09) was observed on PRO compared with PLA throughout recovery. Short-term high dose supplementation of a probiotic beverage containing L.casei before EHS did not attenuate EHS induced endotoxaemia and cytokinaemia; nor is it more positively favorable over a placebo.

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Robert S. Weinberg, Daniel Gould, David Yukelson and Allen Jackson

This investigation was designed to determine the effects of preexisting and manipulated self-efficacy on competitive motor performance. Male (n = 46) and female (n = 46) subjects were classified as being high or low in preexisting self-efficacy before the experiment began and were randomly assigned to either a high- or low-manipulated self-efficacy condition in a 2 × 2 × 2 (sex by self-efficacy by manipulated efficacy) design. Efficacy was manipulated by having subjects compete against a confederate on a muscular leg-endurance task where the confederate was said to be either a varsity track athlete (low-manipulated self-efficacy) or an individual who had had knee surgery (high-manipulated self-efficacy). To create aversive consequences, the experiment was rigged so that subjects lost in competition on the two muscular leg endurance task trials they performed. Both preexisting and manipulated self-efficacy were found to significantly influence performance, with preexisting self-efficacy influencing performance only on Trial 1 and manipulated self-efficacy only on Trial 2. The findings support Bandura's (1977) theory of self-efficacy and are discussed in terms of the permeability of initial efficacy states.

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David B. Pyne, Joshua H. Guy and Andrew M. Edwards

Heat and immune stress can affect athletes in a wide range of sports and environmental conditions. The classical thermoregulatory model of heat stress has been well characterized, as has a wide range of practical strategies largely centered on cooling and heat-acclimation training. In the last decade evidence has emerged of an inflammatory pathway that can also contribute to heat stress. Studies are now addressing the complex and dynamic interplay between hyperthermia, the coagulation cascade, and a systemic inflammatory response occurring after transient damage to the gastrointestinal tract. Damage to the intestinal mucosal membrane increases permeability, resulting in leakage of endotoxins into the circulation. Practical strategies that target both thermoregulatory and inflammatory causes of heat stress include precooling; short-term heat-acclimation training; nutritional countermeasures including hydration, energy replacement, and probiotic supplementation; pacing strategies during events; and postevent cooling measures. Cooperation between international, national, and local sporting organizations is required to ensure that heat-management policies and strategies are implemented effectively to promote athletes’ well-being and performance.

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Gabriella Berwig Möller, Maria Júlia Vieira da Cunha Goulart, Bruna Bellincanta Nicoletto, Fernanda Donner Alves and Cláudia Dornelles Schneider

the gut barrier function by decreasing splanchnic blood flow by up to 80% of baseline levels and increasing gut permeability ( Briza et al., 2010 ; Monda et al., 2017 ). Intense exercise triggers an inflammatory and immune response, increases reactive oxygen species and unbalance of the brain

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Jennifer Ostrowski, Angelina Purchio, Maria Beck, JoLynn Leisinger, Mackenzie Tucker and Sarah Hurst

One of the primary goals during immediate care of orthopedic injury is to decrease tissue temperature in order to slow metabolism in the area, 1 , 2 cause vasoconstriction of superficial tissues, 3 – 5 decrease permeability, 6 prevent secondary tissue death, 7 – 9 and prevent edema formation. 6

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Reid Reale, Gary Slater, Gregory R. Cox, Ian C. Dunican and Louise M. Burke

permeability of the collecting ducts and, thus, water reabsorption, via the insertion of aquaporin channels ( Verbalis, 2003 ), notably, the aquaporin-2 (AQP2) channels. Conversely, in the absence of vasopressin, AQP2 channels (thus water reabsorption) are reduced ( Verbalis, 2003 ), assisting acute fluid

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Thilo Hotfiel, Marion Kellermann, Bernd Swoboda, Dane Wildner, Tobias Golditz, Casper Grim, Martin Raithel, Michael Uder and Rafael Heiss

concentration, which is considered to activate proteolytic enzymes, to increase cell membrane permeability, and to lead to a release of interstitial fluid. 39 The inflammatory triggered responses are in line with our results, as we are able to describe significant changes in the tissue elasticity and an

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Alan J. McCubbin, Anyi Zhu, Stephanie K. Gaskell and Ricardo J.S. Costa

Lambert , G.P. , Broussard , L.J. , Mason , B.L. , Mauermann , W.J. , & Gisolfi , C.V. ( 2001 ). Gastrointestinal permeability during exercise: Effects of aspirin and energy-containing beverages . Journal of Applied Physiology, 90 ( 6 ), 2075 – 2080 . PubMed ID: 11356768 doi: 10