High training loads or prolonged bouts of acute exercise can increase susceptibility to opportunistic infections. Such infections, although generally medically innocuous, can have profound negative implications for athletic performance. This thesis presents a series of studies investigating which factors influence infection risk in athletes, as well as exploring potential strategies to maintain immunocompetence during heavy training. In Chapters 2 and 3, a large cohort of elite winter endurance athletes were followed over a number of years to determine patterns and frequency of illness in this population, and to identify training- and competition-related predictors of infection. Incidence rates and seasonal patterns of illness were found to be broadly similar to elite athletes from summer sports, and to the general population. Competition, air travel, greater day-to-day fluctuations in training load and lower performance level were significant predictors of illness. When high training loads are combined with insufficient recovery, athletes may become overreached or overtrained. Previous studies suggest that increasing carbohydrate intake can be an effective means of preventing overreaching during periods of intense training. In Chapter 4 we therefore investigated the efficacy of carbohydrate supplementation in reducing immune disturbances and symptoms of overreaching. The lower carbohydrate does (20 g/h during exercise) was found to be equally effective in preserving immunity and power output as the higher dose (60 g/h), with modest immune and performance changes observed in both groups following eight days of intensified training. Many athletes fail to ingest sufficient fluid to maintain euhydration during exercise. However, Chapter 5 found that moderate hypohydration, elicited by a 24 h period of fluid restriction, had little effect on immune responses to prolonged exercise. Altitude training is an important component of the training process of most of today s elite endurance athletes. Chapters 6 and 7 explored the effects of acute and prolonged hypoxic training on immunity. Despite a somewhat augmented stress hormone response to exercise in hypoxia, altitude training was found to have little negative effect on host defence, providing relative exercise intensity at altitude and sea-level was matched.

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Various national and international standards recommend potable water for mixing concrete; however, the availability of potable water is virtually a daunting task in some developing communities. Concrete workers in such environments tend to utilize any available water for mixing concrete, and this may be detrimental to the quality of the concrete being produced. This study investigates the rheological, mineralogical and strength variability of concrete due to construction water impurities. Water samples were collected from four different construction sites within Southwestern region of Nigeria for production of concrete. The physical and chemical properties of the waters were determined so as to measure their rate of contamination, prior to their use for mixing concrete. The rheological properties of the fresh concrete, compressive strength, split tensile strength, and microscale features of hardened concrete, that were produced with each water sample were determined. From the results, the rheological features of concrete were found not to be affected by water impurities, however, the mechanical test results revealed about 10% reduction in strength between concrete made with water having least and higher concentration of impurities. Also, it was evident from the microscale tests that the water impurities do alter the hydration rate of concrete, which results in strength reduction. The study suggests pretreatment of concrete mixing water before use in order to avoid its damaging effect on concrete life. / Revisión por pares

Purpose: The purpose of this study was to determine how differences in hydration states and ion content of hydrating fluids affected bioelectrical impedance (BI) and hydrostatic weighing (HW) measurements. Methods: Fifteen athletic subjects aged 19-56 yr were recruited. Relative body fat (%), fat- weight (FW), and fat-free weight (FW) were assessed using BI and HW under normal conditions (N), hypohydration (HPO), rehydration (RHY), and superhydration (SHY) states. During the RHY and SHY trial periods, subjects were hydrated with either distilled water or an electrolyte solution (ELS). HPO and SHY levels were set at 3% of each person's normally hydrated body weight. Results: Comparison between the distilled water and the ELS trials indicated that hydration solution had no effect on BI or HW. Thus, the results presented are the trial means of both hydration solutions combined. Both BI and HW were shown to be highly test-retest reliable (r-values: 0.96 and 0.99, respectively). The effects of exercise induced HPO followed by RHY on body composition values indicated that HW was very stable across measurement periods while BI was not. From N to the HPO state, BI %BF declined from 14.4 ± 5.3% to 12.3 ± 5.3%, respectively. After RHY, BIA %BF increased to 15.5 ± 5.8%. Similar findings occurred when subjects were superhydrated (N-BI = 13.2 ± 5.3%; SHY-BI = 15.4 ± 5.6%). With a comparison of the intercepts and slopes of HW and BIA for the N and SHY states, it was clear hydration status significantly affected the intercepts (HW: 0.37 vs. BI: 1.85) and not the slopes (HW: 1.00 vs BI: 0.99). As a result, a majority of all fluid changes were interpreted as FW by BI. During HPO, 82% of the weight loss was considered FW while during RHY or SHY, 128% and 85% of the water weight regain/gain was considered FW. Conclusion: These results indicate that BI is not a valid technique in athletes, especially when wanting to determine body composition effects of training/detraining. This study indicates that even small fluid changes such as those that occur with endurance training may be interpreted incorrectly as changes in an athlete's body fat content.

Title: Comparing hydration practices of long-distance runners during intended training, an intended event, and an actual event during COVID-19. Context: Prior studies on long-distance runners have yet to compare hydration practices intended in training to an actual event. Optimal hydration strategies and knowledge of EAH was assessed. Objective: The purpose of this research was to assess and compare the self-reported hydration practices of long-distance runners during an intended training run, an intended event, and during an event. Design: Cross-sectional online survey design Setting: 2020 Hyannis, Massachusetts Marathon; Connecticut trail races; online. Participants: There were 46 participants in the Hyannis, 26 participants in the Connecticut trail races, and 203 participants in the long-distance running studies. Main outcome Measure(s): Survey questions addressed hydration practices, including hydration strategies, and volumes consumed before and during a run. Additional data included demographics, training experience, sources of hydration information, and knowledge of EAH. Results: When comparing volumes consumed, higher correlations were found when comparing intended events in all three studies. In other words, runners intended to drink the same in an intended training run and an intended event. More variation was found when comparing intended volumes to actual volumes. All studies showed strong agreement in the selected hydration strategies between the scenarios and most were statistically significant. The “drinking to thirst hydration strategy”, was selected on average 17% of the time for Hyannis marathoners, 30% of the time for Connecticut trail runners, and 23% of the time for long-distance runners. This hydration strategy is recommended to decrease the risk of EAH in lieu of a personalized hydration plan. EAH awareness among runners was reported between 50-59% of the time in all studies. However, there was inconsistency in recognizing contributing and preventive EAH factors. Conclusion: There were differences in hydration practices when comparing an intended training run, an intended event, and an event. This indicates a need for ongoing education on hydration practices and EAH. If runners mimic appropriate hydration practices during training when running in an event, the risk of EAH may be decreased. The limitation of this research is the self-reported nature of historical data.

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Thesis advisor: Ethan Baxter / Serpentinites assume a critical role in geochemical and geophysical cycles, from recycling fluid into the sub-arc mantle to facilitating exhumation within subduction zones. Rodingite dikes can be used as a lens to investigate the hydration of the oceanic lithosphere as their development is synchronous with serpentinization, and while serpentinites lack sufficient mineral phases for geochronology, rodingite dikes are rich in andradite and grossular garnet which are potentially amenable for geochronology. This research seeks to constrain the timescales and duration of hydration of the oceanic lithosphere within the Alpine Tethys ocean basin, and associated serpentinization, by examining Apennines rodingites from the Internal Ligurides (Italy). These rodingites experienced seafloor hydrothermal alteration and were obducted onto the continental margin during Alpine orogenesis. As a result, they are ideal for studying seafloor metasomatism as they were not affected by prograde subduction zone metamorphism and dehydration. Sr isotopic and trace element profiles were constructed across two rodingite-serpentinite transects, revealing a complex, multi-stage hydration history consisting of 1) Widespread serpentinization, 2) Gabbroic intrusions, 3) Rodingitization, and 4) Localized, late-stage advective fluid flow. Serpentinizing fluids locally display strong continental crustal isotopic signatures, while rodingitization fluids are characterized by seawater-like values. U-Pb geochronology on rodingite garnets produced an age of 96.1 ± 8.9 Ma, which could represent either the main rodingitization phase or the late-stage advective alteration. / Thesis (MS) — Boston College, 2023. / Submitted to: Boston College. Graduate School of Arts and Sciences. / Discipline: Earth and Environmental Sciences.

The purpose of this study was to analyze and quantify the effects of a nebulized saline treatment on speech production in eight females with Primary Sjögren's Syndrome (SS). The duration, formant frequency onset and offset, and slope were measured to determine the quality of participants' production of diphthongal American English vowels. Acoustic data were examined before treatment began, immediately following treatment, and during a one-week follow-up to determine the effects of a laryngeal hydration program that used nebulized saline to increase hydration of structures in the vocal tract. The vowels produced during the initial baseline condition were acoustically relatively similar to the productions of typical speakers not diagnosed with SS. Although some differences in mean vowel duration and formant frequency values were found in the recorded vowel productions, results indicated that the participants' vowel productions remained relatively stable across the different phases of treatment. The absence of large treatment effects, in terms of vowel acoustics, may be due to the possibility that although the dryness associated with SS is an irratant for speakers, it may not affect their ability to produce diphthongal vowels in a significant manner.

Background: In recent years several state high school athletic association have investigated methods to ensure the health and safety of high school wrestlers. One method implemented by the National Collegiate Athletic Association requires the prediction of minimum weight (MW) prior to the competition season. This weight certification program requires the assessment of body composition and hydration status. Results from those assessments place wrestlers in their lowest allowable wrestling weight class. There are a variety of measurement devises that have proven to be effective in measuring body composition. However, several considerations must be taken into account when choosing a devise such as affordability and reliability. Of those devices leg-to-leg bioelectrical impedance analysis (BIA) has been suggested for use with wrestlers. Purpose: To test the validity of bioelectrical impedance as an instrument of body composition and minimum wrestling weight compared to three-site skinfold using the Lohman-Brozek formula and the Bod Pod®; among hydrated high school wrestlers. Methods: Criterion for this study was the Bod Pod®. Subjects included 98 high school wrestlers taking part in the pre-season wrestling weight certification program implemented by the Virginia High School League. Hydration was assessed and a urine specific gravity (USG) ≤ 1.020 was assigned as the level of hydration. Results: In order to investigate the validity of BIA in this study a repeated measure ANOVA with between-subjects factors was used to assess the equality of means between the three measurement devices. Also, in order to investigate hydration affect subjects were divided into two categories (hydrated and dehydrated). Finally, prior to analysis subjects were placed in weight categories based on their assigned wrestling weight class. Results of this study demonstrated that the three measurement devices did not produce similar results and it was concluded that hydration level had no affect on the measurements. Therefore, at this time BIA should not be considered as an alternative method for assessing body composition in high school wrestling weight certification programs. / Ph. D.

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