Glacial vicariance and secondary contact shape demographic histories in a freshwater mussel species complex.

Characterizing the mechanisms influencing the distribution of genetic variation in aquatic species can be difficult due to the dynamic nature of hydrological landscapes. In North America's Central Highlands, a complex history of glacial dynamics, long-term isolation, and secondary contact have shaped genetic variation in aquatic species. Although the effects of glacial history have been demonstrated in many taxa, responses are often lineage- or species-specific and driven by organismal ecology. In this study, we reconstruct the evolutionary history of a freshwater mussel species complex using a suite of mitochondrial and nuclear loci to resolve taxonomic and demographic uncertainties. Our findings do not support Pleurobema rubrum as a valid species, which is proposed for listing as threatened under the U.S. Endangered Species Act. We synonymize P. rubrum under Pleurobema sintoxia-a common and widespread species found throughout the Mississippi River Basin. Further investigation of patterns of genetic variation in P. sintoxia identified a complex demographic history, including ancestral vicariance and secondary contact, within the Eastern Highlands. We hypothesize these patterns were shaped by ancestral vicariance driven by the formation of Lake Green and subsequent secondary contact after the last glacial maximum. Our inference aligns with demographic histories observed in other aquatic taxa in the region and mirrors patterns of genetic variation of a freshwater fish species (Erimystax dissimilis) confirmed to serve as a parasitic larval host for P. sintoxia. Our findings directly link species ecology to observed patterns of genetic variation and may have significant implications for future conservation and recovery actions of freshwater mussels.

pmartR 2.0: A Quality Control, Visualization, and Statistics Pipeline for Multiple Omics Datatypes.

The pmartR (https://github.com/pmartR/pmartR) package was designed for the quality control (QC) and analysis of mass spectrometry data, tailored to specific characteristics of proteomic (isobaric or labeled), metabolomic, and lipidomic data sets. Since its initial release, the tool has been expanded to address the needs of its growing userbase and now includes QC and statistics for nuclear magnetic resonance metabolomic data, and leverages the DESeq2, edgeR, and limma-voom R packages for transcriptomic data analyses. These improvements have made progress toward a unified omics processing pipeline for ease of reporting and streamlined statistical purposes. The package's statistics and visualization capabilities have also been expanded by adding support for paired data and by integrating pmartR with the trelliscopejs R package for the quick creation of trellis displays (https://github.com/hafen/trelliscopejs). Here, we present relevant examples of each of these enhancements to pmartR and highlight how each new feature benefits the omics community.

Low-volume high-intensity interval training for cardiometabolic health.

High-intensity interval training (HIIT) is characterised by short bouts of high-intensity submaximal exercise interspersed with rest periods. Low-volume HIIT, typically involving less than 15 min of high-intensity exercise per session, is being increasingly investigated in healthy and clinical populations due to its time-efficient nature and purported health benefits. The findings from recent trials suggest that low-volume HIIT can induce similar, and at times greater, improvements in cardiorespiratory fitness, glucose control, blood pressure, and cardiac function when compared to more traditional forms of aerobic exercise training including high-volume HIIT and moderate intensity continuous training, despite requiring less time commitment and lower energy expenditure. Although further studies are required to elucidate the precise mechanisms of action, metabolic improvements appear to be driven, in part, by enhanced mitochondrial function and insulin sensitivity, whereas certain cardiovascular improvements are linked to increased left ventricular function as well as greater central and peripheral arterial compliance. Beyond the purported health benefits, low-volume HIIT appears to be safe and well-tolerated in adults, with high rates of reported exercise adherence and low adverse effects.

Impact of a Mediterranean diet on hepatic and metabolic outcomes in non-alcoholic fatty liver disease: The MEDINA randomised controlled trial.

BACKGROUND: Non-alcoholic fatty liver disease (NAFLD) is predominantly managed by lifestyle intervention, in the absence of effective pharmacotherapies. Mediterranean diet (MedDiet) is the recommended diet, albeit with limited evidence. AIMS: To compare an ad libitum MedDiet to low-fat diet (LFD) in patients with NAFLD for reducing intrahepatic lipids (IHL) by proton magnetic resonance spectroscopy (1 H-MRS). Secondary outcomes include insulin resistance by homeostatic model of assessment (HOMA-IR), visceral fat by bioelectrical impedance analysis (BIA), liver stiffness measurement (LSM) and other metabolic outcomes. METHODS: In this parallel multicentre RCT, subjects were randomised (1:1) to MedDiet or LFD for 12 weeks. RESULTS: Forty-two participants (25 females [60%], mean age 52.3 ± 12.6 years) were included, 23 randomised to LFD and 19 to MedDiet.; 39 completed the study. Following 12 weeks, there were no between-group differences. IHL improved significantly within the LFD group (-17% [log scale]; p = .02) but not within the MedDiet group (-8%, p = .069). HOMA-IR reduced in the LFD group (6.5 ± 5.6 to 5.5 ± 5.5, p < .01) but not in the MedDiet group (4.4 ± 3.2 to 3.9 ± 2.3, p = .07). No differences were found for LSM (MedDiet 7.8 ± 4.0 to 7.6 ± 5.2, p = .429; LFD 11.8 ± 14.3 to 10.8 ± 10.2 p = .99). Visceral fat reduced significantly in both groups; LFD (-76% [log scale], p = <.0005), MedDiet (-61%, p = <.0005). CONCLUSIONS: There were no between-group differences for hepatic and metabolic outcomes when comparing MedDiet to LFD. LFD improved IHL and insulin resistance. Significant improvements in visceral fat were seen within both groups. This study highlights provision of dietary interventions in free-living adults with NAFLD is challenging.

Degree of adiposity and obesity severity is associated with cutaneous microvascular dysfunction in type 2 diabetes.

BACKGROUNDS AND AIMS: Obesity and diabetes independently contribute to cutaneous microvascular dysfunction via pathological processes that are not fully understood. We sought to determine if obesity severity is associated with cutaneous microvascular dysfunction and measures of peripheral arterial disease in adults with type 2 diabetes in cross-sectional observational study design. METHODS AND RESULTS: Primary outcomes were post-occlusive reactive hyperaemia as determined by laser-Doppler fluxmetry (peak flux post-occlusion, time to peak flux post-occlusion, peak as a percentage of baseline, and area under the curve [AuC] index post-occlusion to pre-occlusion). Secondary outcomes were ankle- and toe-brachial indices (ABI and TBI) and systolic toe pressure. Thirty-six participants (20 men, 16 women) with mean age 55 ± 8 years, BMI of 36 ± 5 kg/m2 and duration of diabetes 8 ± 6 years underwent measurements. After adjusting for age and duration of diabetes, SAT and total percentage body fat were able to explain 29% (p = 0.001) and 20% (p = 0.01) of variance of AuC index models, as well as 29% (p = 0.02) and 18% (p = 0.02) of peak as a percentage of baseline models, respectively. Though TBI demonstrated moderate, significant correlations with SAT (r:0.37, p = 0.04) and total percentage body fat (r:0.39, p = 0.03), these were not upheld by regression analyses. Neither ABI nor systolic toe pressure significantly correlated with any measure of adiposity or obesity. CONCLUSION: These findings demonstrate impairment in cutaneous microvascular function related to adiposity and obesity severity in adults with type 2 diabetes, suggesting that obesity may pathologically effect cutaneous microvascular function in the absence of overt macrovascular disease, warranting further investigation.

Comparative phylogenomics reveal complex evolution of life history strategies in a clade of bivalves with parasitic larvae (Bivalvia: Unionoida: Ambleminae).

Freshwater mussels are a species-rich group with biodiversity patterns strongly shaped by a life history strategy that includes an obligate parasitic larval stage. In this study, we set out to reconstruct the life history evolution and systematics in a clade of freshwater mussels adapted to parasitizing a molluscivorous host fish. Anchored hybrid enrichment and ancestral character reconstruction revealed a complex pattern of life history evolution with host switching and multiple instances of convergence, including reduction in size of larvae, increased fecundity, and growth during encapsulation. Our phylogenomic analyses also recovered non-monophyly of taxa exhibiting multiple traits used as the basis for previous taxonomic hypotheses. Taxa with axe-head shaped glochidia were resolved as paraphyletic, but our results strongly suggest the complex morphology is an adaptation to reduce larval size, with reduction in size further accentuated in taxa previously assigned to Leptodea. To more accurately reflect the evolutionary history of this group, we make multiple systematic changes, including the description of a new genus, Atlanticoncha gen. nov., and the synonymy of the genus Leptodea under Potamilus. Our findings contribute to the growing body of literature showing that cladistic hypotheses based solely on morphological characters, including larval morphology, can be flawed in freshwater mussels.

A comprehensive approach uncovers hidden diversity in freshwater mussels (Bivalvia: Unionidae) with the description of a novel species.

Major geological processes have shaped biogeographical patterns of riverine biota. The Edwards Plateau of central Texas, USA, exhibits unique aquatic communities and endemism, including several species of freshwater mussels. Lampsilis bracteata (Gould, 1855) is endemic to the Edwards Plateau region; however, its phylogenetic relationship with other species in the Gulf coastal rivers and Mississippi River basin is unknown. We evaluated phylogenetic relationships, shell morphologies and soft anatomy characters of L. bracteata and a closely related congener, Lampsilis hydiana (Lea, 1838) throughout their ranges. Our results showed the presence of an undescribed species: Lampsilis bergmanni sp.n. Lampsilis bracteata and L. bergmanni sp.n. share similar shell morphologies and soft anatomy characters; however, they are genetically distinct. Geological processes, such as faulting and sea-level changes during the Miocene to Pliocene, are likely to have facilitated diversification of Lampsilis species, resulting in isolation of L. bracteata on the Edwards Plateau and diversification between L. bergmanni sp.n. and L. hydiana. We conclude that L. bracteata range is restricted to the Colorado River basin, whereas L. bergmanni sp.n. occurs only in upstream reaches of the Guadalupe River basin. Conservation actions are warranted for both species due to their restricted distributions and potential anthropogenic threats.

Molecular and morphological data reveal non-monophyly and speciation in imperiled freshwater mussels (Anodontoides and Strophitus).

Accurate taxonomic placement is vital to conservation efforts considering many intrinsic biological characteristics of understudied species are inferred from closely related taxa. The rayed creekshell, Anodontoides radiatus (Conrad, 1834), exists in the Gulf of Mexico drainages from western Florida to Louisiana and has been petitioned for listing under the Endangered Species Act. We set out to resolve the evolutionary history of A. radiatus, primarily generic placement and species boundaries, using phylogenetic, morphometric, and geographic information. Our molecular matrix contained 3 loci: cytochrome c oxidase subunit I, NADH dehydrogenase subunit I, and the nuclear-encoded ribosomal internal transcribed spacer I. We employed maximum likelihood and Bayesian inference to estimate a phylogeny and test the monophyly of Anodontoides and Strophitus. We implemented two coalescent-based species delimitation models to test seven species models and evaluate species boundaries within A. radiatus. Concomitant to molecular data, we also employed linear morphometrics and geographic information to further evaluate species boundaries. Molecular and morphological evidence supports the inclusion of A. radiatus in the genus Strophitus, and we resurrect the binomial Strophitus radiatus to reflect their shared common ancestry. We also found strong support for polyphyly in Strophitus and advocate the resurrection of the genus Pseudodontoideus to represent 'Strophitus' connasaugaensis and 'Strophitus' subvexus. Strophitus radiatus exists in six well-supported clades that were distinguished as evolutionary independent lineages using Bayesian inference, maximum likelihood, and coalescent-based species delimitation models. Our integrative approach found evidence for as many as 4 evolutionary divergent clades within S. radiatus. Therefore, we formally describe two new species from the S. radiatus species complex (Strophitus williamsi and Strophitus pascagoulaensis) and recognize the potential for a third putative species (Strophitus sp. cf. pascagoulaensis). Our findings aid stakeholders in establishing conservation and management strategies for the members of Anodontoides, Strophitus, and Pseudodontoideus.

Reversal of type 2 diabetes in youth who adhere to a very-low-energy diet: a pilot study.

AIMS/HYPOTHESIS: The aim of the study was to investigate whether a very-low-energy diet (VLED) is a feasible and acceptable treatment option for type 2 diabetes in children and adolescents, and whether adherence can lead to rapid weight loss, reversal of type 2 diabetes and reduced liver fat as seen in adult studies. METHODS: Eight participants with type 2 diabetes and obesity, aged 7-16 years, non-medicated (n = 1) or treated with metformin (n = 7) and in some cases insulin (n = 3), followed a VLED (<3360 kJ/day) for 8 weeks, then transitioned to a hypocaloric diet (∼6300 kJ/day) that they followed to 34 weeks. HbA1c, fasting glucose and 2 h post-glucose load plasma glucose (2hG) were determined from fasting blood and an OGTT. Liver fat concentration was quantified using proton magnetic resonance spectroscopy. Adherence was defined as ≥5% weight loss during the 8 week VLED. RESULTS: Adherers (n = 5) and non-adherers (n = 3) had median weight loss of 7.5% and 0.5%, respectively, at 8 weeks. Overall, HbA1c (mean [SE] 8.1% [0.7%] to 6.6% [0.5%]; p = 0.004) and 2hG (15.6 [1.6] mmol/l to 11.3 [1.0] mmol/l; p = 0.009) were significantly reduced at 8 weeks compared with baseline. Liver fat was also significantly reduced from baseline (14.7% [2.2%]) to 8 weeks (5.8% [1.7%]; p = 0.001). Only three out of eight participants met non-alcoholic fatty liver disease (NAFLD) criteria (≥5.5%) at 8 weeks, compared with eight out of eight at baseline. The three participants on insulin therapy at baseline were able to cease therapy during the 8 week VLED. At 34 weeks, adherers (n = 5) achieved 12.3% weight loss, none met NAFLD criteria and four did not meet American Diabetes Association criteria for type 2 diabetes. CONCLUSIONS/INTERPRETATION: A VLED appears to be a feasible treatment option for some youth with type 2 diabetes on metformin therapy. Youth who agree to participate and adhere to a VLED achieve rapid weight loss, dramatic reductions in liver fat and reversal of type 2 diabetes. This highlights the capacity of a VLED to be used as a first-line treatment option in newly diagnosed youth. A larger trial with a control group and longer follow-up will be required to encourage a change in standard treatment. TRIAL REGISTRATION: Australian New Zealand Clinical Trial Registration Number (ACTRN) ACTRN12616000375459 ( www.ANZCTR.org.au/ACTRN12616000375459.aspx ).

NAFLD in clinical practice: Can simple blood and anthropometric markers be used to detect change in liver fat measured by 1 H-MRS?

BACKGROUND & AIMS: Research in NAFLD management is commonly based on quantitative assessment of liver fat by proton-magnetic resonance spectroscopy (1 H-MRS), and translation of this into clinical practice is currently limited by availability and expense. Novel steatosis biomarkers have been proposed for the prediction of liver fatness; however, whether these are suitable for detecting changes in liver fat is unknown. We aimed to determine the accuracy of these indices, and waist circumference (WC), in quantifying longitudinal change in 1 H-MRS-quantified liver fat. METHODS: We performed a secondary analysis using data from 97 overweight/obese adults (age: 39.7±11.5 years, body mass index: 30.7±4.4 kg/m2 , liver fat: 6.0±4.8%, 65% male) who completed either an 8-week exercise or 12-week nutraceutical intervention, with varying degrees of change in liver fat. Baseline and post-intervention measures were liver fat (1 H-MRS), NAFLD Liver Fat Score, Liver Fat Equation (LFE), Fatty Liver Index (FLI), Hepatic Steatosis Index (HSI), the Visceral Adiposity Index (VAI) and WC. RESULTS: Only the change in HSI, FLI and WC was associated with change in liver fat; however, correlations were weak to moderate. There was no agreement between the LFE and 1 H-MRS for detecting liver fat change. Only change in WC significantly affected change in liver fat (P<.001), and WC AUROC for the presence of steatosis was 0.65 and 0.78 for men and women respectively. CONCLUSIONS: Novel indices are limited in their ability to detect longitudinal change in liver fat. Waist circumference may offer modest utility as a surrogate to infer liver fat change with lifestyle interventions.

Effect of resistance training on liver fat and visceral adiposity in adults with obesity: A randomized controlled trial.

AIM: Regular aerobic exercise reduces visceral adipose tissue (VAT) and liver fat, however, not all individuals are able to adopt and adhere to such programs. Progressive resistance training (PRT) may be an alternative therapy, but there is limited available evidence. We examined the efficacy of PRT as per current exercise guidelines, compared with sham exercise placebo on liver fat and VAT. METHODS: Twenty-nine inactive and overweight/obese (body mass index ≥25 kg/m2 ) adults (age 29-59) were randomized to receive 8 weeks of PRT (n = 15, 10 exercises per session, 8-12 repetitions, 2-3 sets per exercise at 80-85% of one-repetition maximum, 3 days per week) or a sham exercise placebo control (CON) (n = 14). Change in liver fat, VAT, and abdominal s.c. adipose tissue (SAT) were assessed by magnetic resonance spectroscopy and imaging). RESULTS: There were no significant group by time interactions for change in liver fat in PRT versus CON groups (-0.07 ± 0.31% vs. 0.55 ± 0.77%, respectively, P = 0.19), VAT (-175 ± 85 cm3 vs. 10 ± 64 cm3 , respectively, P = 0.11), or abdominal SAT (-436 ± 245 cm3 vs. 127.29 ± 182 cm3 , respectively, P = 0.10) despite a significant increase in muscle volume (55 ± 78 cm3 vs. -0.04 ± 8 cm3 , respectively, P = 0.03). CONCLUSION: Traditional PRT is not effective for reducing liver fat in overweight/obese adults compared with placebo control. Although PRT has known metabolic benefits, an adequate volume of aerobic exercise should be promoted if liver fat is the therapeutic target.

Effect of aerobic exercise training dose on liver fat and visceral adiposity.

BACKGROUND & AIMS: Aerobic exercise reduces liver fat and visceral adipose tissue (VAT). However, there is limited data from randomized trials to inform exercise programming recommendations. This study examined the efficacy of commonly prescribed exercise doses for reducing liver fat and VAT using a randomized placebo-controlled design. METHODS: Inactive and overweight/obese adults received 8 weeks of either; i) low to moderate intensity, high volume aerobic exercise (LO:HI, 50% VO 2peak, 60 min, 4d/week); ii) high intensity, low volume aerobic exercise (HI:LO, 70% VO 2peak, 45 min, 3d/week); iii) low to moderate intensity, low volume aerobic exercise (LO:LO, 50% VO 2peak, 45 min, 3d/week); or iv) placebo (PLA). Liver fat (spectroscopy) and VAT (magnetic resonance imaging) were measured before and after intervention. RESULTS: Forty-seven of the 48 (n = 12 in each group) participants completed the trial. There were no serious adverse events. There was a significant change in group × time interaction in liver fat, which reduced in HI:LO by 2.38 ± 0.73%, in LO:HI by 2.62 ± 1.00%, and in LO:LO by 0.84 ± 0.47% but not in PLA (increase of 1.10 ± 0.62%) (p = 0.04). There was a significant reduction in VAT in HI:LO (-258.38 ± 87.78 cm(3)), in LO:HI (-386.80 ± 119.5 cm(3)), and in LO:LO (-212.96 ± 105.54 cm(3)), but not in PLA (92.64 ± 83.46 cm(3)) (p = 0.03). There were no significant differences between the dose or intensity of the exercise regimen and reductions in liver fat or VAT (p > 0.05). CONCLUSION: The study found no difference in efficacy of liver fat reduction by either aerobic exercise dose or intensity. All of the aerobic exercise regimens employed reduced liver fat and VAT by a small amount without clinically significant weight loss.

Efficacy of the Omega-3 Index in predicting non-alcoholic fatty liver disease in overweight and obese adults: a pilot study.

Non-alcoholic fatty liver disease (NAFLD) is an independent predictor of CVD in otherwise healthy individuals. Low n-3 PUFA intake has been associated with the presence of NAFLD; however, the relationship between a biomarker of n-3 status - the Omega-3 Index - and liver fat is yet to be elucidated. A total of eighty overweight adults (fifty-six men) completed the anthropometric and biochemical measurements, including the Omega-3 Index, and underwent proton magnetic resonance spectroscopy assessment of liver fat. Bivariate correlations and multiple regression analyses were performed with reference to prediction of liver fat percentage. The mean Omega-3 Index was high in both NAFLD (intrahepatic lipid concentration≥5·5 %) and non-NAFLD groups. The Omega-3 Index, BMI, waist circumference, glucose, insulin, TAG, high-sensitive C-reactive protein (hsCRP) and alanine aminotransferase (ALT) were positively correlated, and HDL and erythrocyte n-6:n-3 ratio negatively correlated with liver fat concentration. Regression analysis found that simple anthropometric and demographic variables (waist, age) accounted for 31 % of the variance in liver fat and the addition of traditional cardiometabolic blood markers (TAG, HDL, hsCRP and ALT) increased the predictive power to 43 %. The addition of the novel erythrocyte fatty acid variable (Omega-3 Index) to the model only accounted for a further 3 % of the variance (P=0·049). In conclusion, the Omega-3 Index was associated with liver fat concentration but did not improve the overall capacity of demographic, anthropometric and blood markers to predict NAFLD.

The Mediterranean diet improves hepatic steatosis and insulin sensitivity in individuals with non-alcoholic fatty liver disease.

BACKGROUND & AIMS: Non-alcoholic fatty liver disease (NAFLD) affects up to 30% of the population and signifies increased risk of liver fibrosis and cirrhosis, type 2 diabetes, and cardiovascular disease. Therapies are limited. Weight loss is of benefit but is difficult to maintain. We aimed at examining the effect of the Mediterranean diet (MD), a diet high in monounsaturated fatty acids, on steatosis and insulin sensitivity, using gold standard techniques. METHODS: Twelve non-diabetic subjects (6 Females/6 Males) with biopsy-proven NAFLD were recruited for a randomised, cross-over 6-week dietary intervention study. All subjects undertook both the MD and a control diet, a low fat-high carbohydrate diet (LF/HCD), in random order with a 6-week wash-out period in- between. Insulin sensitivity was determined with a 3-h hyperinsulinemic-euglycemic clamp study and hepatic steatosis was assessed with localized magnetic resonance (1)H spectroscopy ((1)H-MRS). RESULTS: At baseline, subjects were abdominally obese with elevated fasting concentrations of glucose, insulin, triglycerides, ALT, and GGT. Insulin sensitivity at baseline was low (M=2.7 ± 1.0 mg/kg/min(-1)). Mean weight loss was not different between the two diets (p=0.22). There was a significant relative reduction in hepatic steatosis after the MD compared with the LF/HCD: 39 ± 4% versus 7 ± 3%, as measured by (1)H-MRS (p=0.012). Insulin sensitivity improved with the MD, whereas after the LF/HCD there was no change (p=0.03 between diets). CONCLUSIONS: Even without weight loss, MD reduces liver steatosis and improves insulin sensitivity in an insulin-resistant population with NAFLD, compared to current dietary advice. This diet should be further investigated in subjects with NAFLD.

The effect of nitrate supplementation on exercise performance in healthy individuals: a systematic review and meta-analysis.

The purpose of this review was to examine the effect of nitrate supplementation on exercise performance by systematic review and meta-analysis of controlled human studies. A search of four electronic databases and cross-referencing found 17 studies investigating the effect of inorganic nitrate supplementation on exercise performance that met the inclusion criteria. Beetroot juice and sodium nitrate were the most common supplements, with doses ranging from 300 to 600 mg nitrate and prescribed in a manner ranging from a single bolus to 15 days of regular ingestion. Pooled analysis showed a significant moderate benefit (ES = 0.79, 95% CI: 0.23-1.35) of nitrate supplementation on performance for time to exhaustion tests (p = .006). There was a small but insignificant beneficial effect on performance for time trials (ES = 0.11, 95% CI: -0.16-0.37) and graded exercise tests (ES = 0.26, 95% CI: -0.10-0.62). Qualitative analysis suggested that performance benefits are more often observed in inactive to recreationally active individuals and when a chronic loading of nitrate over several days is undertaken. Overall, these results suggest that nitrate supplementation is associated with a moderate improvement in constant load time to exhaustion tasks. Despite not reaching statistical significance, the small positive effect on time trial or graded exercise performance may be meaningful in an elite sport context. More data are required to clarify the effect of nitrate supplementation on exercise performance and to elucidate the optimal way to implement supplementation.

The effect of ice slushy ingestion and mouthwash on thermoregulation and endurance performance in the heat.

PURPOSE: The purpose of this study was to establish whether sensory factors associated with cold-beverage ingestion exert an ergogenic effect on endurance performance independent of thermoregulatory or cardiovascular factors. METHODS: Ten males performed three trials involving 90 min of steady state cycling (SS; 62% VO2max) in the heat (32.1 ± 0.9 °C, 40 ± 2.4% relative humidity) followed by a 4 kJ/kg body mass time trial (TT). During SS, participants consumed an identical volume (260 ± 38 g) of sports beverage (7.4% carbohydrate) every 15 min as either ice slushy (-1 °C; ICE), thermoneutral liquid (37 °C; CON), or thermoneutral liquid consumption with expectorated ice slushy mouthwash (WASH). RESULTS: Rectal temperature, hydration status, heart rate, and skin blood flow were not different between trials. Gastrointestinal (pill) temperature was lower in ICE (35.6 ± 2.7 °C) versus CON (37.4 ± 0.7 °C, p = .05). Heat storage tended to be lower with ICE during SS (14.7 ± 8.4 W.m(-2), p = .08) and higher during TT (68.9 ± 38.6 W.m(-2), p = .03) compared with CON (22.1 ± 6.6 and 31.4 ± 27.6 W.m(-2)). ICE tended to lower the rating of perceived exertion (RPE, 12.9 ± 0.6, p = .05) and improve thermal comfort (TC, 4.5 ± 0.2; p = .01) vs. CON (13.8 ± 1.0 and 5.2 ± 0.2 respectively). WASH RPE (13.0 ± 0.8) and TC (4.8 ± 0.2) tended to be lower versus CON (p = .07 and p = .09 respectively). ICE improved performance (18:28 ± 1:03) compared with CON (20:24 ± 1:46) but not WASH (19:45 ± 1:43). CONCLUSION: Improved performance with ICE ingestion likely resulted from the creation of a gastrointestinal heat sink, reducing SS heat storage. Although the benefits of cold-beverage consumption are more potent when there is ingestion, improved RPE, TC, and meaningful performance improvement with WASH supports an independent sensory effect of presenting a cold stimulus to the mouth.

Case study: beverage temperature at aid stations in ironman triathlon.

PURPOSE: The aim of this study was to measure the effect of environmental conditions and aid-station beverage- cooling practices on the temperature of competitor beverages. METHODS: Environmental and beverage temperatures were measured at three cycling and two run course aid stations at the 2010 Langkawi, Malaysia (MA), and Port Macquarie, Australia (AU), Ironman triathlon events. To measure the specific effect of radiant temperature, additional fluid-filled (600 ml) drink bottles (n = 12) were cooled overnight (C) and then placed in direct sun (n = 6) or shade (n = 6) near to a cycle aid station at AU. RESULTS: During both events, beverage temperature increased over time (p < .05) as environmental conditions, particularly radiant temperature increased (p < .05). Mean beverage temperature ranged between 14-26°C and during both events was above the palatable range (15-22°C) for extended periods. At AU, bottles placed in direct sunlight heated faster (6.9 ± 2.3 °C·h-1) than those in the shade (4.8 ±1.1°C·h-1, p = .05). CONCLUSION: Simple changes to Ironman aid-station practices, including shade and chilling beverages with ice, result in the provision of cooler beverages. Future studies should investigate whether provision of cool beverages at prolonged endurance events influences heat-illness incidence, beverage-consumption patterns, and competitor performance.

Training practices and ergogenic aids used by male bodybuilders.

Bodybuilding involves performing a series of poses on stage where the competitor is judged on aesthetic muscular appearance. The purpose of this study was to describe training practices and ergogenic aids used by competitive bodybuilders and to determine whether training practices comply with current recommendations for muscular hypertrophy. A web-based survey was completed by 127 competitive male bodybuilders. The results showed that during the off-season phase of training (OFF), the majority of respondents performed 3-6 sets per exercise (95.3%), 7-12 repetition maximum (RM) per set (77.0%), and 61- to 120-seconds recovery between sets and exercises (68.6%). However, training practices changed 6 weeks before competition (PRE), where there was an increased number of respondents who reported undertaking 3-4 sets per exercise at the expense of 5-6 sets per exercise (p < 0.001), an increase in the number reporting 10-15RM per set from 7-9RM per set (p < 0.001), and an increase in the number reporting 30-60 seconds vs. 61-180 seconds recovery between sets and exercises (p < 0.001). Anabolic steroid use was high among respondents competing in amateur competitions (56 of 73 respondents), whereas dietary supplementation was used by all respondents. The findings of this study demonstrate that competitive bodybuilders comply with current resistance exercise recommendations for muscular hypertrophy; however, these changed before competition during which there is a reduction resistance training volume and intensity. This alteration, in addition to an increase in aerobic exercise volume, is purportedly used to increase muscle definition. However, these practices may increase the risk of muscle mass loss in natural compared with amateur bodybuilders who reportedly use drugs known to preserve muscle mass.

Exercise in the Management of Metabolic-Associated Fatty Liver Disease (MAFLD) in Adults: A Position Statement from Exercise and Sport Science Australia.

Metabolic-associated fatty liver disease (MAFLD) is the most prevalent chronic liver disease worldwide, affecting 25% of people globally and up to 80% of people with obesity. MAFLD is characterised by fat accumulation in the liver (hepatic steatosis) with varying degrees of inflammation and fibrosis. MAFLD is strongly linked with cardiometabolic disease and lifestyle-related cancers, in addition to heightened liver-related morbidity and mortality. This position statement examines evidence for exercise in the management of MAFLD and describes the role of the exercise professional in the context of the multi-disciplinary care team. The purpose of these guidelines is to equip the exercise professional with a broad understanding of the pathophysiological underpinnings of MAFLD, how it is diagnosed and managed in clinical practice, and to provide evidence- and consensus-based recommendations for exercise therapy in MAFLD management. The majority of research evidence indicates that 150-240 min per week of at least moderate-intensity aerobic exercise can reduce hepatic steatosis by ~ 2-4% (absolute reduction), but as little as 135 min/week has been shown to be effective. While emerging evidence shows that high-intensity interval training (HIIT) approaches may provide comparable benefit on hepatic steatosis, there does not appear to be an intensity-dependent benefit, as long as the recommended exercise volume is achieved. This dose of exercise is likely to also reduce central adiposity, increase cardiorespiratory fitness and improve cardiometabolic health, irrespective of weight loss. Resistance training should be considered in addition to, and not instead of, aerobic exercise targets. The information in this statement is relevant and appropriate for people living with the condition historically termed non-alcoholic fatty liver disease (NAFLD), regardless of terminology.