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- Genre: Academic theses
- Status: Published
Initial FB and HS were assessed in NCAA-DI female soccer athletes (n=10) of a single team in temperate, dry conditions (55-68°F, 18-48% humidity) who were monitored during 3 practices of equal estimated energy expenditure (EE): two outdoors in direct SUR (cold/moderate temperatures) and one indoors without SUR (moderate temperatures). Humidity, temperature, and wet bulb globe temperature (WBGT – a measurement partly based on SUR, including ambient temperature/relative humidity) were recorded using Heat Stress Meters placed in the direct sun or in the shade. Each athlete’s semi-nude dry body weight was recorded before and after exercise. Urine samples were taken before, after, and the morning after. Urine specific gravity (USG) was tested to assess HS. Athletes wore combined heart rate and activity monitors to estimate EE and were provided ad libitum water and/or a zero-calorie sports drink. Their total intake included weights of consumed food and drink. Sweat rate was calculated using body weight change and intakes of liquids minus urine losses/hour.
Two-way repeated measures ANOVA analyzed group-level differences. No significance was found in total FB (1.01±0.32 L/hr) or EE/hr (444±97.1 kcal/hr) across all days (p>0.05). In analyzing individual athlete results, 40% had consistent USG >1.025 (p=0.001) suggesting potential dehydration. These 4 athletes selected water as their beverage, of which is known that consuming only water does not stimulate drinking behavior as does electrolyte drinks. The remaining 60% were overall not dehydrated (USG <1.025) but must be aware of incidental dehydration in hotter temperatures.
The conclusion is that in low-moderate temperatures, athletes self-regulate drinking habits and achieve fluid balance during exercise with or without sun radiation. However, athletes with average USG >1.025 are likely to remain dehydrated in moderate temperatures. The findings suggest that more education would benefit these athletes by ensuring hydration in any environment.
Methods: Forty-two healthy six-week old male Sprague-Dawley rats were randomly assigned to one of three groups: plain water control, 0.6 mg/ml organometallic complex or 3.0 mg/ml organometallic complex as soon as they arrived. Each rat was then housed individually to prevent the sharing of microbiota through coprophagia. Rats in each treatment group were further divided into two dietary groups that were fed either a high fat diet containing 60% kcal fat that was changed every three days or standard rodent chow. Researchers were not blind to which rat was in each group. At the end of the 10-week study, rats were euthanized with an overdose of sodium pentobarbital (200 mg/kg, i.p.). Heart, left ventricle of the heart, liver, and spleen masses were recorded for each animal. Data were analyzed by two-way ANOVA using SigmaPlot 10.0 software.
Results: At the conclusion of this study, the left ventricle mass of the rats in the high fat diet group were significantly larger than those in the chow group. Neither dose of the organometallic complex supplement prevented these effects induced by high fat feeding.
Conclusion: The organometallic complex supplement was not effective at mitigating the effects of a high fat diet on cardiac hypertrophy in rats. Therefore, this supplement should not be used to treat cardiac hypertrophy.
This study investigated the effect of environmental heat stress on physiological and performance measures during a ~4 mi time trial (TT) mountain hike in the Phoenix metropolitan area. Participants (n = 12; 7M/5F; age 21.6 ± 2.47 [SD]) climbed ‘A’ mountain (~1 mi) four times on a hot day (HOT; wet bulb globe temperature [WBGT] = 31.6°C) and again on a moderate day (MOD; WBGT = 19.0°C). Physiological and performance measures were made before and throughout the course of each hike. Mean pre-hike hydration status (urine specific gravity [USG]) indicated that participants began both HOT and MOD trials in a euhydrated state (1.016 ± 0.010 and 1.010 ± 0.008, respectively) and means did not differ significantly between trials (p = .085). Time trial performance was impaired by -11% (11.1 minutes) in the HOT trial (105 ± 21.7 min), compared to MOD (93.9 ± 13.1 min) (p = .013). Peak core temperatures were significantly higher in HOT (38.5 ± 0.36°C) versus MOD (38.0 ± 0.30°C) with progressively increasing differences between trials over time (p < .001). Peak ratings of perceived exertion were significantly higher in HOT (14.2 ± 2.38) compared to MOD (11.9 ± 2.02) (p = .007). Relative intensity (percent of age-predicted maximal heart rate [HR]), estimated absolute intensity (metabolic equivalents [METs]), and estimated energy expenditure (MET-h) were all increased in HOT, but not significantly so. The HOT condition reduced predicted maximal aerobic capacity (CRFp) by 6% (p = .026). Sweat rates differed significantly between HOT (1.38 ± 0.53 L/h) and MOD (0.84 ± 0.27 L/h) (p = .01). Percent body mass loss (PBML) did not differ significantly between HOT (1.06 ± 0.95%) and MOD (0.98 ± 0.84%) (p = .869). All repeated measures variables showed significant between-subjects effects (p < .05), indicating individual differences in response to test conditions. Heat stress was shown to negatively affect physiological and performance measures in recreational mountain hikers. However, considerable variation exists between individuals, and the degree of physiological and performance impairment is probably due, in part, to differences in aerobic fitness and acclimatization status rather than pre- or during-performance hydration status.
In various studies, sumac, a Mediterranean spice and known antioxidant,39,7,66,67 has been shown to have antioxidant properties through its ability to inhibit reactive oxygen species (ROS) such as superoxide.39,7,66,67 Sumac has also been found to reduce TNF-alpha.100 Results from a study of hypertensive human subjects fed a sumac supplement showed a decrease in blood pressure.59
In the current study, COX-2 levels were determined to evaluate the level of inflammation in response to palmitate when primary aortic human vascular smooth muscle cells (HAoVSM) were treated with sumac. The treatments included: vehicle (bovine serum albumin), 100 µM palmitate, and 10, 20, 40, 60, and 80 µg/mL sumac. Sumac did not alter COX-2 protein levels between vehicle and sumac groups. Additional studies were designed to examine whether 80 µg/mL sumac could reverse impaired vasodilation caused by 10 weeks of high fat intake, consisting of 60% of total calories from fat, in Sprague-Dawley rats. Mesenteric arteries were isolated and exposed to sumac. High fat diet (HFD) arteries had impaired vasodilation compared to arteries from chow-fed fats. HFD arteries exposed to sumac had similar endothelium-dependent vasodilation responses as those not exposed to sumac, however, there were trends for improved vasodilation. I suggest that sumac likely exhibits antioxidant capabilities that prevent superoxide from decreasing the bioavailability of nitric oxide in the vasculature, thus promoting endothelium-dependent vasodilation and preventing the creation of more harmful reactive oxygen species. Isolated arteries from chow fed rats developed irreversible vasodilation when exposed to sumac and were therefore not responsive to pre-constriction with phenylephrine (PE) likely related to nitrates and gallic acid naturally present in sumac whereby inhibiting PE.