The Impact of Simulated Altitude on Selected Elements of Running Performance

Background: Simulating altitude at sea level is increasingly more popular among recreationally-trained athletes across the sports spectrum. The AltO2Lab is a commercially-available, handheld, rebreathing apparatus purported to simulate altitude. Currently, there is an overall dearth of evidence regarding the efficacy of the device. Purpose: The goal of this study was to add evidence supporting or challenging the effectiveness of the device to improve selected running performance-related variables and to investigate the time-course of changes should benefits be evidenced. Methods: The 37-day protocol included familiarization, baseline, and 2 follow-up visits during which time hematological (hematocrit and lactate), physiological (running economy, maximal VO2, and heart rate), and psychological (Borg RPE) variables were monitored at rest, during relative submaximal, and/or maximal treadmill exercise. Altitude training days (18 days; one hour each day) were fitted within the 37-day time-line to occur after the baseline visit but before the respective follow-up visits. Specifically, the altitude training took place in 3, 6-day blocks of device usage with exposure, monitored by oximetry, intensifying across the days and blocks. Twelve days of altitude training were completed before the first follow-up visit while the final 6 days of altitude training were completed between the first and second follow-up visit. In this manner, the follow-ups could serve to evaluate the potential effectiveness of the device and narrow the time course of changes to a specific usage duration. Results: Six, recreationally-trained athletes (Females = 4; Males = 2; Age = 22.0 ± 2.9 yrs.; Baseline VO2max 52.7 ± 6.7) enrolled in the study. One subject was removed due to noncompliance. Overall, simulated altitude at the prescribed, intensifying dosage, failed to change both hematocrit (p = 0.469) and VO2max (p = 0.184) when analyzed by repeated measures analysis of variance. Additionally, no differences were found for secondary variables including: running economy, heart rate, lactate or RPE (all p \u3e 0.05). Conclusion: Presently, the AltO2Lab failed to improve selected variables related to running performance. This finding is in contrast to previous investigations with the device but it does align with the knowledge that a stronger stimulus might be necessary to induce HIF-mediated erythropoiesis to the extent that the cascade could alter hematological and subsequently performance ability through enhanced oxygen-carrying capacity. These results are preliminary and a final cohort will complete testing before concluding results will be disseminated

Pre-Prandial Vinegar Ingestion Improves Two-Hour Glucose Control in Older, Type II Diabetics More Than Post-Prandial Walking

Background: Exercise engagement benefits diabetic patients through an insulin-like effect on muscle. Literature indicates that vinegar consumption may lower blood glucose levels. It is not currently clarified whether a relative amount of vinegar ingestion or a walking bout is more effective at controlling glucose in older, Type II diabetics during the acute phase following a meal. Purpose: The aim was to directly compare the impact of preferred-pace walking (15 min, postprandial) versus ingestion of a relative quantity of vinegar (0.3 g/kg) on two-hour glucose control. Methods: The two arms of the trial were completed in a randomized, crossover manner. Six Type II diabetic patients (Females = 5; Males = 1; Age = 70.5 ± 9.0 yrs.) enrolled and underwent baseline finger pricks to establish glucose levels. The test meal consisted of an 85 g bagel, 13 g of butter, and 237 mL of orange juice. On the respective days, the vinegar was diluted into 59 mL of orange juice and ingested before the meal or the subject completed a 15-min walk at 15 min post-meal. For both trials, glucose was checked every 30 min following the test meal. Results: One subject was removed from all present analysis due to medication-related non-compliance. For the vinegar trial, the resting heart rate was 72.0 (± 9.5) and baseline, 30-, 60-, 90-, and 120-min average blood glucose levels were: 117 (±12), 149 (±39), 172 (±49), 185 (±49), and 180 (±44) mg/dl. For the preferred walking speed phase, the resting heart rate was 75.5 (±15.6) and baseline, 30-, 60-, 90-, and 120-min average glucose levels were: 113 (±10), 147 (±53), 180 (±53), 208 (±72), and 206 (±71) mg/dl. Preferred walking speed was found to average 3.1 (± 1.5) kph and total steps averaged 1418 (±376). The between-arm comparison of glucose at 120-min trended towards significance (p = 0.081). Conclusions: Compared with a bout of walking, a relative quantity of vinegar may serve as a more suitable mechanism for older Type II diabetics to control acute spikes in glucose after a high carbohydrate meal. With an adequately-powered analysis, between-arm comparisons at multiple time-points would likely have achieved statistical significance. Nevertheless, the meaningfulness of the glucose control exhibited should not be lost due to the lack of statistical significance. Finally, the slow absolute preferred walking pace of many older adults may undermine the ability for walking to result in sufficient energy expenditure capable of subsequent glucose control

GENETIC AND METABOLIC FACTORS SHAPING FUNCTIONAL AND SYSTEMIC RECOVERY POST-SPINAL CORD INJURY: A FOCUS ON APOE

There are currently approximately 300,000 individuals living with a spinal cord injury (SCI) in the United States with an additional 17,000 injuries occurring each year. Perhaps of equal importance the median age at which an SCI occurs within the population has steadily increased since the 1970s to the 2010s from 29 years to 43 years and is still on the rise. Women, historically underrepresented in biomedical research, have also seen a slight increase in SCI incidence. This increase in age of injury onset means that more people with an SCI will be impacted by genetic factors associated with Alzheimer’s disease (AD). Therefore, it’s critical to examine not only the impact of the apolipoprotein E (APOE) gene typically associated with AD, but also sex as a biological variable in the context of SCI. Additionally, while the central nervous system (CNS) comprising of the brain and spinal cord has been extensively studied in the context of AD and SCI respectively, little is known about how SCI affects peripheral organs, including those involved in ApoE production such as the liver. Based on prior work conducted in our lab examining the impact high cervical injury on respiratory outcomes, including preliminary work investigating APOE, and the need for an injury rostral to the level of peripheral organ innervation we chose to utilize the left lateral C2 hemisection (C2Hx) to characterize our genotype and peripheral organ outcome measures. The APOE gene contains 3 distinct alleles, APOE2, E3, and E4. The E4 allele is the key genetic determinant for Alzheimer’s disease. The E2 genotype is considered protective although it is only found in 5-10 % of the population. For our initial experiments we compared targeted replacement homozygous E3 mice to homozygous E4 counterparts. We first focused on breathing function as measured by whole body plethysmography (WBP) in the absence of a spinal cord injury. We demonstrated that under normal breathing conditions, E3 mice exhibited more robust respiratory function compared to their E4 counterparts. However, when subjected to more severe respiratory challenges, such as those seen in sleep apnea, E4 carriers were able to match or even surpass the respiratory performance of E3 mice. Importantly, previous work from the Alilain lab had observed enhanced plasticity measures in female E3 carriers compared to E4 counterparts using electromyography. Building on our initial work characterizing respiratory responses without an SCI, we expanded our investigation to examine how C2Hx impacts measures of respiratory and motor recovery in our APOE mouse model as well as relevant spinal cord histopathology. First, we utilized WBP to evaluate the respiratory responses in E3 and E4 mice. We determined that even following an SCI, E3 mice breathe more robustly except when a more severe challenge is administered at which point E4 mice increase their breathing rate more than their E3 counterparts. Next, we examined measures of gait dynamics and locomotor coordination showing that at least in male mice, E4 animals displayed better recovery post injury. Finally, we performed immunohistochemistry on regions critical to respiratory and motor control to characterize differences in plasticity, inflammation, and myelination between our genotypes. Having further established the critical role of sex and APOE genotype in SCI recovery, we explored metabolomics as a technique that could expand our understanding of injury profiles and be integrated into future studies of our APOE mouse model. To determine how SCI impacts the peripheral organ metabolome, we gave a C2Hx to female rats and examined organs at acute timepoints post-injury as well as from a naïve group. For our peripheral organs, we chose the lungs, spleen, and liver due to their relevance to breathing, immune function, and ApoE production, respectively. We found significant upregulation of energy production substrates in the liver following injury. While changes in our other peripheral organs were less pronounced, the metabolomic shift in the liver presents an excellent target for investigation and intervention, particularly in the context of our APOE mouse model. Furthermore, our metabolomics work builds on preliminary studies from other groups initially defining a tertiary injury. This tertiary injury is characterized by changes in peripheral organs following the well-established secondary injury that occurs in the cord, which is characterized by CNS cell death and spinal cord degeneration subsequent to the initial traumatic primary injury. These findings further highlight the importance of APOE genotype and sex on respiratory and motor recovery following SCI. Furthermore, a better understanding of the impact of these factors on SCI recovery, as well as a more precise characterization of our tertiary injury hypothesis will aid in overcoming translational barriers in the treatment of SCI. This work holds the potential to uncover new therapeutic approaches for SCI treatment both in the context of individual genetics and the peripheral organ metabolome

The Need for Reporting Metabolic Sampling Interval in Publication: An Example Using Maximal VO2 Values and Running Economy

Background: Knowledge of metabolic outcomes, such as maximal oxygen consumption (VO2) or running economy, has wide-ranging application. Metabolic outcomes are widely reported in literature yet the metabolic sampling interval (example: breath-by-breath, 30-sec average) utilized for collection is rarely ever stated. Purpose: The purposes of the present investigation were to probe the potential discrepancies created when analyzing running economy and VO2max raw metabolic data with four different metabolic sampling intervals. Methods: Five recreationally-active and endurance-trained subjects were included in the present analysis and four metabolic sampling intervals were analyzed: 30-sec average, 20-sec average, 8-breath, and 4-breath. Subjects engaged in 4-min running economy phases at 55 and 65% of their VO2max before entering into a maximal protocol purposed to elicit VO2max in 8-12 minutes. Utilizing the steady state and maximal VO2 data, metabolic sampling intervals were analyzed for their effect on reported VO2 values. Results: For running economy at 55%, there was no differences found (f = 0.207; df = 1.862; p = 0.799) between sampling frequencies when analyzed by repeated measures analysis of variance and corrected with Greenhouse-Geisser for a violation of sphericity. For running economy at 65%, there were also no differences ­found (f = 1.456; df = 3; p = 0.799) between sampling frequencies. For inspection, the relative VO2 values were: 27.2 (±3.1), 27.9 (±4.1), 28.4 (±3.6), and 28.8 (±5.1) for the 30-sec, 20-sec, 8-breath, and 4-breath average, respectively. Maximal VO2 values of 53.0 (±6.6), 55.1 (±7.2), 55.1 (±7.2), and 59.6 (±9.4) for the 30-sec, 20-sec, 8-breath, and 4-breath average, respectively, were found to be significantly different (f = 21.062; df = 1.278; p \u3c 0.001) after adjusting for a violation of sphericity (p \u3c 0.001). Bonferroni analysis indicated differences between the 30-sec average and all other averages and also the 20-sec and 8-breath averages when compared against the 4-breath average. The 4-breath average yielded the highest VO2max value. Coincidentally, the 20-sec and 8-breath averages were identical. Conclusion: In the present investigation of raw metabolic data, sampling interval was found to impact the maximal oxygen consumption (VO2max) values but not running economy values when investigating a small sample of data with four select sampling intervals. The report of maximal VO2 is rather common in the literature and knowing sample interval is vital for between-study comparison, determination of regression-related activities, or for pre-post comparison of data from the same or different labs

Protostellar mass accretion rates from gravoturbulent fragmentation

We analyse protostellar mass accretion rates from numerical models of star formation based on gravoturbulent fragmentation, considering a large number of different environments. To within one order of magnitude, the mass accretion rate is approximately given by the mean thermal Jeans mass divided by the corresponding free-fall time. However, mass accretion rates are highly time-variant, with a sharp peak shortly after the formation of the protostellar core. We present an empirical exponential fit formula to describe the time evolution of the mass accretion and discuss the resulting fit parameters. There is a positive correlation between the peak accretion rate and the final mass of the protostar. We also investigate the relation of the accretion rate with the turbulent flow velocity as well as with the driving wavenumbers in different environments. We then compare our results with other theoretical models of star formation and with observational data.Comment: 13 pages, 6 figures; accepted by A&

Well-being and philosophy of science

This article is a mutual introduction of the science of well-being to philosophy of science and an explanation of how the two disciplines can benefit each other. In the process I argue that the science of well-being is not helpfully viewed as a social or a natural, but rather as a mixed, science. Hence its methodology will have to attend to its specific features. I discuss two of its methodological problems: justifying the role of values, and validating measures. I suggest that tackling them calls for developing mid-level rather than high theories of well-being.This is the author's accepted manuscript and will be under embargo until 24 months after the date of publication. The final version is available from Wiley at onlinelibrary.wiley.com/doi/10.1111/phc3.12203/abstrac

Elatinaceae are Sister to Malpighiaceae; Peridiscaceae Belong to Saxifragales

Phylogenetic data from plastid (ndhF and rbcL) and nuclear (PHYC) genes indicate that, within the order Malpighiales, Elatinaceae are strongly supported as sister to Malpighiaceae. There are several putative morphological synapomorphies for this clade; most notably, they both have a base chromosome number of X = 6 (or some multiple of three or six), opposite or whorled leaves with stipules, unicellular hairs (also uniseriate in some Elatinaceae), multicellular glands on the leaves, and resin (Elatinacae) or latex (Malpighiaceae). Further study is needed to determine if these features are synapomorphic within the order. Malpighiaceae have previously been inferred as sister to Peridiscaceae based on rbcL sequence data, but the rbcL sequence of Whittonia is a chimera of two sequences, neither of which appears to be Whittonia. Our data from plastid (atpB, rbcL) and nuclear (18S rDNA) genes instead place Peridiscaeace as a member of the Saxifragales.Organismic and Evolutionary Biolog