The effects of hypoxia on hunger perceptions, appetite-related hormone concentrations and energy intake:A systematic review and meta-analysis

Exposure to hypoxia appears to depress appetite and energy intake, however the mechanisms are not fully understood. The aim of this review was to determine the magnitude of changes in hunger and energy intake in hypoxic compared with normoxic environments, and establish any alterations in appetite-related hormone concentrations. PubMed and The Cochrane Library as well as MEDLINE, SPORTDiscus, PsycINFO and CINAHL, via EBSCOhost, were searched through 1st April 2017 for studies that evaluated hunger, energy intake and/or appetite-related hormones in normoxia and during hypoxic exposure in a within-measures design. A total of 28 studies (comprising 54 fasted and 22 postprandial comparisons) were included. A random-effects meta-analysis was performed to establish standardised mean difference (SMD) with 95% confidence intervals. Hypoxic exposure resulted in a trivial but significant decrease in postprandial hunger scores (SMD: −0.15, 95% CI: −0.29 to −0.01; n = 14; p = 0.043) and a moderate decrease in energy intake (SMD: −0.50, 95% CI: −0.85 to −0.15; n = 8; p = 0.006). Hypoxic exposure resulted in a decrease (albeit trivial) in postprandial acylated ghrelin concentrations (SMD: −0.16, 95% CI: −0.25 to −0.08; n = 7; p &lt; 0.0005), and a moderate increase in fasted insulin concentrations (SMD: 0.41, 95% CI: 0.17 to 0.65; n = 34; p = 0.001). Meta-regression revealed a decrease in postprandial acylated ghrelin concentrations (p = 0.010) and an increase in fasted insulin concentrations (p = 0.020) as hypoxic severity increased. Hypoxic exposure reduces hunger and energy intake, which may be mediated by decreased circulating concentrations of acylated ghrelin and elevated insulin concentrations. PROSPERO registration number: CRD42015017231.</p

Can grit be taught? Lessons from a nationwide field experiment with middle-school students

We study whether a particular socio-emotional skill - grit (the ability to sustain effort and interest towards long-term goals) - can be cultivated through a large-scale program, and how this affects student learning. Using a randomized control trial, we evaluate the first nationwide implementation of a low-cost intervention designed to foster grit and self-regulation among sixth and seventh-grade students in primary schools in North Macedonia (about 33,000 students across 350 schools). The results of this interventions are mixed. Exposed students report improvements in self-regulation, in particular the perseverance-of-effort facet of grit, relative to students in a control condition. Impacts on students are larger when both students and teachers are exposed to the curriculum than when only students are treated. For disadvantaged students, we also find positive impacts on grade point averages, with gains of up to 28 percent of a standard deviation one-year post-treatment. However, while this intervention made students more perseverant and industrious, it reduced the consistency-of-interest facet of grit. This means that exposed students are less able to maintain consistent interests for long periods

Effects on mortality of shielding clinically extremely vulnerable patients in Liverpool, UK, during the COVID-19 pandemic

Objective This study evaluates the impact of England’s COVID-19 shielding programme on mortality in the City of Liverpool in North West England. Study Design Shielded and non-shielded people are compared using data from linked routine health records on all people registered with a general practitioner in Liverpool from April 2020 to June 2021. Methods A discrete time hazard model and interactions between the shielding status and the periods of higher risk of transmission are used to explore the effects of shielding across the major phases of the COVID-19 pandemic. Results Shielding was associated with a 34% reduction in the risk of dying (HR= 0.66, 95% CI 0.58 to 0.76) compared with a propensity-matched non-shielded group. Shielding appeared to reduce mortality during the first and third wave, but not the second wave, where shielding was not mandated by Government. The effects were similar for males and females, but more protective for those living in the least deprived areas of Liverpool. Conclusions It is likely that the shielding programme in Liverpool saved lives, although this seems to have been a little less effective in more deprived areas. A comprehensive programme of identifying vulnerable groups and providing them with advice and support is likely to be important for future respiratory virus pandemics. Additional support may be necessary for socioeconomically disadvantaged groups to avoid increased inequalities

Fuel Use during Exercise at Altitude in Women with Glucose–Fructose Ingestion

Purpose: This study compared the co-ingestion of glucose and fructose on exogenous and endogenous substrate oxidation during prolonged exercise at terrestrial high altitude (HA) versus sea level, in women. Method: Five women completed two bouts of cycling at the same relative workload (55% Wmax) for 120 minutes on acute exposure to HA (3375m) and at sea level (~113m). In each trial, participants ingested 1.2 g.min-1 of glucose (enriched with 13C glucose) and 0.6 g.min-1 of fructose (enriched with 13C fructose) before and every 15 minutes during exercise. Indirect calorimetry and isotope ratio mass spectrometry were used to calculate fat oxidation, total and exogenous carbohydrate oxidation, plasma glucose oxidation and endogenous glucose oxidation derived from liver and muscle glycogen. Results: The rates and absolute contribution of exogenous carbohydrate oxidation was significantly lower at HA compared with sea level (ES>0.99, P<0.024), with the relative exogenous carbohydrate contribution approaching significance (32.6±6.1 vs. 36.0±6.1%, ES=0.56, P=0.059) during the second hour of exercise. In comparison, no significant differences were observed between HA and sea level for the relative and absolute contributions of liver glucose (3.2±1.2 vs. 3.1±0.8%, ES=0.09, P=0.635 and 5.1±1.8 vs. 5.4±1.7 grams, ES=0.19, P=0.217), and muscle glycogen (14.4±12.2% vs. 15.8±9.3%, ES=0.11, P=0.934 and 23.1±19.0 vs. 28.7±17.8 grams, ES=0.30, P=0.367). Furthermore, there was no significant difference in total fat oxidation between HA and sea level (66.3±21.4 vs. 59.6±7.7 grams, ES=0.32, P=0.557). Conclusion: In women, acute exposure to HA reduces the reliance on exogenous carbohydrate oxidation during cycling at the same relative exercise intensity

Pathology Testing at the Point of Patient Care: Transformational Change for Rural Communities

Point-of-care (POC) testing is an innovative and revolutionary in vitro diagnostic (IVD) technology that enables the real-time conduct of pathology testing during a patient consultation, facilitating immediate clinical action. When conducted under a quality-assured framework, POC testing is an essential diagnostic tool, and is now well embedded, in primary health care settings in rural communities around the world. POC testing helps bridge the gap in health equity access that exists in geographically isolated rural communities and empowers patients to invest in understanding and improving their own health literacy. Using POC testing networks for chronic, acute and infectious diseases that are currently operating in rural and remote Australia, this chapter explores the operational, clinical and economic benefits that POC testing can deliver, and the lessons learned that have contributed to continuously improved quality of POC testing service delivery. Investment in POC testing and infrastructure by Australian governments, both federal and state, has reaped significant rewards for patients in rural communities. Additionally, translational research in this field has provided insight into how POC testing can be successfully scaled up for broad application in low- and middle-income countries

Mouth Rinsing With Carbohydrate Solutions at the Postprandial State Fail to Improve Performance During Simulated Cycling Time Trials.

Mouth-rinsing with carbohydrate solutions during cycling time trials results in performance enhancements, however the majority of studies have utilised ∼6% carbohydrate solutions. Therefore, the purpose of this study was to compare the effectiveness of mouth-rinsing with 4%, 6%, and 8% carbohydrate (CHO) solutions on 1-h simulated cycling time trial performance. On four occasions, seven trained male cyclists completed at the postprandial period, a set amount of work as fast as possible in a randomised, counterbalanced order. The subjects mouth rinsed for 5-s, upon completion of each 12.5% of the trial, with 25 mL of a non-CHO placebo, 4%, 6%, and 8% CHO solutions. No additional fluids were consumed during the time trial. Heart rate (HR), ratings of perceived exertion (RPE), thirst (TH) and subjective feelings (SF) were recorded after each rinse. Further, blood samples were drawn every 25% of the trial to measure blood glucose (BG) and blood lactate (BG) concentrations, whilst whole body carbohydrate oxidation was monitored continuously. Time to completion was not significant between conditions with the placebo, 4%, 6%, and 8% conditions completing the trials in 62.0 ± 3.0, 62.8 ± 4.0, 63.4 ± 3.4, and 63 ±4.0 minutes respectively. There were no significant differences between conditions in any of the variables mentioned above however significant time effects were observed for HR, RPE, TH, and SF. Post-hoc analysis showed that TH and SF of subjects in the CHO conditions but not in the placebo were significantly increased by completion of the time trial. In conclusion, mouth-rinsing with CHO solutions did not impact 1-h cycling performance in the postprandial period and in the absence of fluid intake. Our findings suggest that there is scope for further research to explore the activation regions of the brain and whether they are receptive to CHO dose, before specific recommendations for athletic populations are established. Consequently mouth-rinsing as a practical strategy for coaches and athletes is questionable under specific conditions and should be carefully considered before its inclusion. The emphasis should be focused on appropriate dietary and fluid strategies during training and competition

Geologic predictors of drinking water well contamination in North Carolina

More than 200 million people worldwide, including 11 million in the US, are estimated to consume water containing arsenic (As) concentrations that exceed World Health Organization and US EPA standards. In most cases, the As found in drinking water wells results from interactions between groundwater and geologic materials (geogenic contamination). To that end, we used the NCWELL database, which contains chemical information for 117,960 private drinking wells across North Carolina, to determine the spatial distribution of wells containing As contaminated water within geologic units. Specific geologic units had large percentages (up to 1 in 3) of wells with water exceeding the EPA As maximum contaminant level (MCL, 10 μg/L), both revealing significant variation within areas that have been previously associated with As contamination and identifying as yet unidentified problematic geologic units. For the 19 geologic units that have >5% of wells that contain water with As concentrations in exceedance of 10 μg/L, 12 (63%) are lithogenically related to the Albemarle arc, remnants of an ancient volcanic island, indicating the importance of volcanogenic materials, as well as recycled (eroded and deposited) and metamorphosed volcanogenic material. Within geologic units, wells that have As concentrations exceeding 10 μg/L tended to have pH values greater than wells with As concentrations less than 10 μg/L, emphasizing the importance of the extent of interaction between groundwater and geologic materials. Using census information with the geologic-based exceedance percentages revealed the importance of regional geology on estimates of population at risk compared to estimates based on county boundaries. Results illustrate that relating As contamination to geologic units not only helps explain sources of geogenic contamination but sharpens the identification of communities at risk for exposure and further illuminates problematic areas through geologic interpretation

A high fat breakfast attenuates the suppression of appetite and acylated ghrelin during exercise at simulated altitude.

High-altitude exposure induces a negative energy balance by increasing resting energy expenditure and decreasing energy intake. This diminished energy intake is likely caused by altitude-induced anorexia and can have detrimental effects for those travelling to high-altitude. We aimed to investigate whether altering the macronutrient composition of breakfast could attenuate altitude-induced anorexia and augment energy intake at high-altitude. Twelve healthy men (aged 26 (8) years, body mass index 23.9 (2.7) kg·m(-2)) completed two, 305min experimental trials at 4300m simulated altitude (~11.7% O2). After an overnight fast, participants entered a normobaric hypoxic chamber and rested for one hour, before receiving either a high fat (HF; 60% fat, 25% carbohydrate) or an isocaloric high carbohydrate (HC; 60% carbohydrate, 25% fat) breakfast. One hour after breakfast, participants performed 60min of treadmill walking at 50% of relative V̇O2max. An ad-libitum buffet meal was consumed 1h 30min after exercise. Appetite perceptions, blood samples and substrate oxidation rates were measured throughout. A significantly higher area under the curve for composite appetite score was observed during exercise in HF (40 (12) mm·h(-1)) compared with HC (30 (17) mm·h(-1), P=0.036). During exercise, lower insulin concentrations (P=0.013) and elevated acylated ghrelin concentrations (P=0.048) were observed in HF compared with HC. After exercise there was no significant difference in composite appetite score (P=0.356), acylated ghrelin (P=0.229) or insulin (P=0.513) between conditions. Energy intake at the buffet did not significantly differ between conditions (P=0.384). A HF breakfast attenuated appetite suppression during exercise at 4300m simulated altitude, however ad-libitum energy intake did not increase

Dietary nitrate supplementation enhances high-intensity running performance in moderate normobaric hypoxia, independent of aerobic fitness.

Nitrate-rich beetroot juice (BRJ) increases plasma nitrite concentrations, lowers the oxygen cost (V̇O2) of steady-state exercise and improves exercise performance in sedentary and moderately-trained, but rarely in well-trained individuals exercising at sea-level. BRJ supplementation may be more effective in a hypoxic environment, where the reduction of nitrite into nitric oxide (NO) is potentiated, such that well-trained and less well-trained individuals may derive a similar ergogenic effect. We conducted a randomised, counterbalanced, double-blind placebo controlled trial to determine the effects of BRJ on treadmill running performance in moderate normobaric hypoxia (equivalent to 2500 m altitude) in participants with a range of aerobic fitness levels. Twelve healthy males (V̇O2max ranging from 47.1 to 76.8 ml kg(-1)·min(-1)) ingested 138 ml concentrated BRJ (∼15.2 mmol nitrate) or a nitrate-deplete placebo (PLA) (∼0.2 mmol nitrate). Three hours later, participants completed steady-state moderate intensity running, and a 1500 m time-trial (TT) in a normobaric hypoxic chamber (FIO2 ∼15%). Plasma nitrite concentrations were significantly greater following BRJ versus PLA 1 h post supplementation, and remained higher in BRJ throughout the testing session (p  0.05). These findings suggests that a high nitrate dose in the form of a BRJ supplement may improve running performance in individuals with a range of aerobic fitness levels conducting moderate and high-intensity exercise in a normobaric hypoxic environment

DACC Resting State Functional Connectivity as a Predictor of Pain Symptoms Following Motor Vehicle Crash: A Preliminary Investigation

There is significant heterogeneity in pain outcomes following motor vehicle crashes (MVCs), such that a sizeable portion of individuals develop symptoms of chronic pain months after injury while others recover. Despite variable outcomes, the pathogenesis of chronic pain is currently unclear. Previous neuroimaging work implicates the dorsal anterior cingulate cortex (dACC) in adaptive control of pain, while prior resting state functional magnetic resonance imaging studies find increased functional connectivity (FC) between the dACC and regions involved in pain processing in those with chronic pain. Hyper-connectivity of the dACC to regions that mediate pain response may therefore relate to pain severity. The present study completed rsfMRI scans on N=22 survivors of MVCs collected within two weeks of the incident to test whole-brain dACC-FC as a predictor of pain severity six months later. At two weeks, pain symptoms were predicted by positive connectivity between the dACC and the premotor cortex. Controlling for pain symptoms at two weeks, pain symptoms at six months were predicted by negative connectivity between the dACC and the precuneus. Previous research implicates the precuneus in the individual subjective awareness of pain. Given a relatively small sample size, approximately half of which did not experience chronic pain at six months, findings warrant replication. Nevertheless, this study provides preliminary evidence of enhanced dACC connectivity with motor regions and decreased connectivity with pain processing regions as immediate and prospective predictors of pain following MVC. Perspective: This article presents evidence of distinct neural vulnerabilities that predict chronic pain in motor vehicle crash survivors based on whole-brain connectivity with the dorsal anterior cingulate cortex