Joyner, Michael J

Abstract Females likely experience larger performance benefits from androgenic‐anabolic steroids than males. We set out to determine if there were temporal differences in select athletics (track and field) records between females and males. Exploratory aims included: (1) evaluating the improvements in female and male world records over time, and (2) investigating the influence of doping programs on male and female world records before and after 1990, when sports governing bodies began to implement random out‐of‐competition and systematic in‐competition drug testing. We collected the top 500 performances of all time for both sexes from an online database (worldathletics.org) in four running events (100, 200, 400 and 800 m) and two throwing events (discus throw and shot‐put). Data were stratified into quintiles based on world record ranking (1st to 100th, 101st to 200th, etc.). The temporal distribution of the top 100 female performers was significantly earlier than the top 100 male performers (year: 2000 ± 1 vs. 2005 ± 1, respectively; P < 0.0001). Within the event, the top performances occurred significantly earlier for females in the 800 m (year: 1995 ± 15 vs. 2003 ± 12; P = 0.0007) and shot‐put (year: 1992 ± 14 vs. 2003 ± 17; P = 0.0004). Among females, world records rapidly improved through the 1980s, but following 1990, the world records ceased to improve. Geographically, there was a greater representation of countries with state‐sponsored doping programs, specifically among female performances. We postulate these sex differences in the temporal distribution of top performances are likely associated with enhanced effectiveness of exogenous androgens (steroid doping) among female athletes with lower endogenous androgen hormones compared to males.

The purpose of sympathetic neuronal discharge and the recruitment of neuronal subpopulations for human circulatory homeostasis remains unknown. This study tested the hypothesis that sympathetic neuronal discharge and recruitment patterns regulate neuropeptide Y (NPY) bioavailability. Across baseline and an intravenous dexmedetomidine infusion (α2-adrenergic agonist) sympathetic action potential (AP) frequency and total sympathetic AP clusters were associated with NPY bioavailability. This is the first study to report that sympathetic neuronal discharge and recruitment patterns regulate NPY bioavailability to support circulatory homeostasis in humans.

We performed 6-yr follow-up testing on a world record-breaking master marathon runner. We determined that his performance declined since his record-breaking marathon in 2018 primarily due to a reduction in V̇o2max. His max heart rate (HR) changed minimally, but his peak O2 pulse decreased, suggesting that his maximal stroke volume and/or arteriovenous O2 difference decreased. These changes likely reflect primarily age-related effects in the absence of an overt pathological disease process.

In the Spring of 2020, the United States of America (USA) deployed COVID-19 convalescent plasma (CCP) to treat hospitalized patients. Over 500,000 patients were treated with CCP during the first year of the pandemic. In this study, we estimated the number of actual inpatient lives saved by CCP treatment in the United States of America based on CCP weekly use, weekly national mortality data, and CCP mortality reduction data from meta-analyses of randomized controlled trials and real-world data. We also estimate the potential number of lives saved if CCP had been deployed for 100% of hospitalized patients or used in 15 to 75% of outpatients. Depending on the assumptions modeled in stratified analyses, we estimated that CCP saved between 16,476 and 66,296 lives. The CCP ideal use might have saved as many as 234,869 lives and prevented 1,136,133 hospitalizations. CCP deployment was a successful strategy for ameliorating the impact of the COVID-19 pandemic in the USA. This experience has important implications for convalescent plasma use in future infectious disease emergencies.

Three-dimensional reconstruction of airways has shown increased luminal area in patients with COVID-19 and post-acute sequelae of COVID-19 when compared with healthy controls. These findings suggest the role of large conducting airways in the pathogenesis of post-acute sequelae of COVID 19.

This study provides a novel understanding on baroreflex control of efferent sympathetic nervous system activity during competing stressors: baroreflex loading and peripheral chemoreflex activation. We show chemoreflex activation buffers baroreflex-mediated reductions in sympathetic nervous system activity. More importantly, baroreflex loading reduced baroreflex threshold gain of sympathetic action potential clusters and this reduction withstood chemoreflex activation. These data suggest the arterial baroreflex holds a primary regulatory role over medium-sized sympathetic neurons despite competing chemoreflex signals.

BACKGROUND: Alcohol consumption is associated with cardiovascular disease, and the sympathetic nervous system is a suspected mediator. The present study investigated sympathetic transduction of muscle sympathetic nerve activity to blood pressure at rest and in response to cold pressor test following evening binge alcohol or fluid control, with the hypothesis that sympathetic transduction would be elevated the morning after binge alcohol consumption. METHODS: Using a randomized, fluid-controlled (FC) crossover design, 26 healthy adults (12 male, 14 female, 25±6 years, 27±4 kg/m 2 ) received an evening binge alcohol dose and a FC. All participants underwent next-morning autonomic-cardiovascular testing consisting of muscle sympathetic nerve activity, beat-to-beat blood pressure, and heart rate during a 10-minute rest period and a 2-minute cold pressor test. Sympathetic transduction was assessed at rest and during the cold pressor test in both experimental conditions. RESULTS: Evening alcohol increased heart rate (FC: 60±9 versus alcohol: 64±9 bpm; P =0.010) but did not alter resting mean arterial pressure (FC: 80±6 versus alcohol: 80±7 mm Hg; P =0.857) or muscle sympathetic nerve activity (FC: 18±9 versus alcohol: 20±8 bursts/min; P =0.283). Sympathetic transduction to mean arterial pressure (time×condition; P =0.003), diastolic blood pressure (time×condition; P =0.010), and total vascular conductance (time×condition; P =0.004) was augmented after alcohol at rest. Sympathetic transduction during the cold pressor test was also elevated after evening binge alcohol consumption ( P =0.002). CONCLUSIONS: These findings suggest that evening binge alcohol consumption leads to augmented morning-after sympathetic transduction of muscle sympathetic nerve activity to blood pressure, highlighting a new mechanism whereby chronic or excessive alcohol consumption contributes to cardiovascular disease progression via altered end-organ responsiveness to sympathetic neural outflow. REGISTRATION: URL: https://clinicaltrials.gov/study/NCT03567434 ; Unique identifier: NCT03567434.