The effect of betaine on nitric oxide and cardiovascular response to exercise

The purpose of this study was to investigate the effects of acute betaine (BT) supplementation, and exercise, on plasma nitric oxide (NO) levels and the related cardiovascular response (CVR). [This is an excerpt from the abstract. For the complete abstract, please see the document.

The Effects of Energy Intake on Upper Respiratory Symptoms in Ultra-Endurance Triathletes

Background: It is unclear whether energy intake can impact the incidence of upper respiratory symptoms (URS). The purpose of this study was to examine if there are differences in energy intake between symptomatic (SYM) and asymptomatic (ASYM) groups of URS in Ironman-triathletes. Methods: Thirty-three subjects competing in the Lake Placid Ironman-triathlon (mean±SD; age,37±8y; height,178±8cm; mass,76.3±10.4kg; body fat,10.8±3.8%) were randomized into either the control (CON) or intervention (INT). INT consumed 4-commercial recovery drinks, two immediately post-race and two 3-hours post-race. Calorie and macronutrient intake were recorded pre-, during, and post-race. Subjects completed the Wisconsin URS Survey to assess URS over the next two weeks. Two analyses were done by comparing results between CON and INT, and when subjects were classified as either asymptomatic (ASYM=20) or symptomatic (SYM=13). Results: There were no differences in energy intake (p\u3e0.05) and URS (INT,32±38; CON,16±23; p=0.155). However, on the race day, SYM (9,044±2,598kcal) consumed less energy intake than ASYM (10,991±2497kcal) (p=0.044). Also, SYM consumed less energy the day before the race (p=0.031) and post-race (p=0.008). ASYM consumed greater carbohydrate the day before the race (p=0.032), fat the day of the race (p=0.006), carbohydrate post-race (p=0.08) and fat post-race (p=0.002). Conclusions: Overall energy intake was similar between CON and INT. However, when subjects were differentiated by URS, SYM consumed less calories the day before and day of the race versus ASYM

Dark Matter in Dwarf Spheroidals I: Models

This paper introduces a new two-parameter family of dwarf spheroidal (dSph) galaxy models. The density distribution has a Plummer profile and falls like the inverse fourth power of distance in projection, in agreement with the star-count data. The first free parameter controls the velocity anisotropy, the second controls the dark matter content. The dark matter distribution can be varied from one extreme of mass-follows-light through a near-isothermal halo with flat rotation curve to the other extreme of an extended dark halo with harmonic core. This family of models is explored analytically in some detail -- the distribution functions, the intrinsic moments and the projected moments are all calculated. For the nearby Galactic dSphs, samples of hundreds of discrete radial velocities are becoming available. A technique is developed to extract the anisotropy and dark matter content from such data sets by maximising the likelihood function of the sample of radial velocities. This is constructed from the distribution function and corrected for observational errors and the effects of binaries. Tests on simulated data sets show that samples of 1000 discrete radial velocities are ample to break the degeneracy between mass and anisotropy in the nearby dSphs. Interesting constraints can already be placed on the distribution of the dark matter with samples of 160 radial velocities (the size of the present-day data set for Draco).Comment: 16 pages, version in press at MNRA

Effect of betaine supplementation on cycling sprint performance

<p>Abstract</p> <p>Purpose</p> <p>To examine the effect of betaine supplementation on cycling sprint performance.</p> <p>Methods</p> <p>Sixteen recreationally active subjects (7 females and 9 males) completed three sprint tests, each consisting of four 12 sec efforts against a resistance equal to 5.5% of body weight; efforts were separated by 2.5 min of cycling at zero resistance. Test one established baseline; test two and three were preceded by seven days of daily consumption of 591 ml of a carbohydrate-electrolyte beverage as a placebo or a carbohydrate-electrolyte beverage containing 0.42% betaine (approximately 2.5 grams of betaine a day); half the beverage was consumed in the morning and the other half in the afternoon. We used a double blind random order cross-over design; there was a 3 wk washout between trials two and three. Average and maximum peak and mean power were analyzed with one-way repeated measures ANOVA and, where indicated, a Student Newman-Keuls.</p> <p>Results</p> <p>Compared to baseline, betaine ingestion increased average peak power (6.4%; p < 0.001), maximum peak power (5.7%; p < 0.001), average mean power (5.4%; p = 0.004), and maximum mean power (4.4%; p = 0.004) for all subjects combined. Compared to placebo, betaine ingestion significantly increased average peak power (3.4%; p = 0.026), maximum peak power max (3.8%; p = 0.007), average mean power (3.3%; p = 0.034), and maximum mean power (3.5%; p = 0.011) for all subjects combined. There were no differences between the placebo and baseline trials.</p> <p>Conclusions</p> <p>One week of betaine ingestion improved cycling sprint power in recreationally active males and females.</p

Police-initiated diversion for youth to prevent future delinquent behavior: a systematic review

BackgroundOverly punitive responses to youth misconduct may have the unintended consequence ofincreasing the likelihood of future delinquency; yet, overly lenient responses may fail to serveas a corrective for the misbehavior. Police diversion schemes are a collection of strategiespolice can apply as an alternative to court processing of youth. Police-initiated diversionschemes aim to reduce reoffending by steering youth away from deeper penetration into thecriminal justice system and by providing an alternative intervention that can help youthaddress psychosocial development or other needs that contribute to their problem behavior.ObjectivesThe objective of this review was to synthesize the evidence on the effectiveness of pre-courtinterventions involving police warning or counseling and release, and cautioning schemes inreducing delinquent behavior.Search methodsA combination of 26 databases and websites were searched. References of relevant reviewswere also scanned to identify studies. We also consulted with experts in the field. Searcheswere executed by two reviewers and conducted between August 2016 and January 2017.Selection criteriaOnly experimental and quasi-experimental designs were eligible for this review. All quasiexperimentaldesigns must have had a comparison group similar to the police diversionintervention group with respect to demographic characteristics and prior involvement indelinquent behavior (i.e., at similar risk for future delinquent behavior). Additionally, studiesmust have included youth participants between 12 and 17 years of age who either underwenttraditional system processing or were diverted from court processing through a police-leddiversion program. Studies were also eligible if delinquency-related outcomes, includingofficial and non-official (self-report or third-party reporting) measures of delinquency werereported.Data collection and analysisThis study used meta-analysis to synthesize results across studies. This method involvedsystematic coding of study features and conversion of study findings into effect sizesreflecting the direction and magnitude of any police-led diversion effect. There were 19independent evaluations across the 14 primary documents coded for this review. From this,we coded 67 effect sizes of delinquent behavior post diversion across 31 diversion-traditionalprocessing comparisons. We analyzed these comparisons using two approaches. The firstapproach selected a single effect size per comparison based on a decision rule and the secondused all 67 effect sizes, nesting these within comparison condition and evaluation design.ResultsThe general pattern of evidence is positive, suggesting that police-led diversion modestlyreduces future delinquent behavior of low-risk youth relative to traditional processing.Authors’ conclusionsThe findings from this systematic review support the use of police-led diversion for low-riskyouth with limited or no prior involvement with the juvenile justice system. Thus, policedepartments and policy-makers should consider diversionary programs as part of the mix ofsolutions for addressing youth crime

Effectiveness of an Intermittent Heat Exposure Protocol to Maintain Heat Acclimation

Background: Heat acclimation (HA) adaptations are temporary and must be sustained for the continued safety of those periodically exerting themselves in hot conditions. Purpose: To assess whether an intermittent exercise-heat exposure protocol can mitigate HA decay 25 days after initial acclimation. Methods: Sixteen males (VO2max=54.98±5.5 ml·kg-1·min-1) were pair-matched using physical training duration, VO2max, and body surface area then randomly allocated to a no heat (NHE; n=7) or intermittent exercise-heat exposure (IHE; n=9) group. All participants heat acclimated by completing 10-11 days of low-to-moderate intensity exercise (90-240 min) in hot conditions (40°C, 40%RH). Both groups completed a Pre HA and Post HA heat stress test (HST) consisting of two hours of exercise at 45% VO2max in hot conditions to assess HA. After Post HA, participants completed the HST in either a hot (IHE; 40°C, 37%RH) or thermoneutral environment (NHE; 24°C, 21%RH) every fifth day for 25 days with both groups exercising in the hot condition at day 25 (+25d). Thermoregulatory, cardiovascular, and circulating biomarkers of stress were evaluated. Self-led out-of-lab physical activity duration and intensity (heart rate [HR]) were recorded for 25 days after HA. Results: Both groups heat acclimated as post-exercise HR and rectal temperature (Tre) were lower and sweat rate higher at Post HA versus Pre HA (all p≤0.05). At +25d, post-exercise HR was attenuated in IHE versus NHE (mean difference [NHE-IHE]=28 bpm (95%CI [8, 48], effect size [ES]=1.41, p=0.01) but sweat rate (0.13 L·hr-1, 95%CI [-0.21, 0.46], ES=0.36, p=0.44), skin temperature (0.65°C (95%CI [-0.17, 1.47], ES=0.85, p=0.11) and Tre (0.47°C, 95%CI [-0.24, 1.19], ES=0.68, p=0.18) were similar. Post-exercise cortisol and epinephrine concentrations were higher in NHE versus IHE at +25d (p≤0.046). At +25d, heat adaptation decay was greater in NHE than IHE for Tre (87% versus 2.7%), skin temperature (44% versus 18%), and HR (163% versus 53%). Out-of-lab exercise intensity and +25d post-exercise HR were inversely related in IHE (r=-0.89, p=0.017). Conclusions: Periodic exercise-heat exposure every five days mitigated rectal temperature decay and cardiovascular strain 25 days after initial HA efforts. Intense exercise in thermoneutral environments in addition to exercise-heat stress after HA aids in minimizing adaptation decay

Effect of betaine supplementation on cycling sprint performance

Purpose: To examine the effect of betaine supplementation on cycling sprint performance.Methods: Sixteen recreationally active subjects (7 females and 9 males) completed three sprint tests, each consisting of four 12 sec efforts against a resistance equal to 5.5% of body weight; efforts were separated by 2.5 min of cycling at zero resistance. Test one established baseline; test two and three were preceded by seven days of daily consumption of 591 ml of a carbohydrate-electrolyte beverage as a placebo or a carbohydrate-electrolyte beverage containing 0.42% betaine (approximately 2.5 grams of betaine a day); half the beverage was consumed in the morning and the other half in the afternoon. We used a double blind random order cross-over design; there was a 3 wk washout between trials two and three. Average and maximum peak and mean power were analyzed with one-way repeated measures ANOVA and, where indicated, a Student Newman-Keuls.Results: Compared to baseline, betaine ingestion increased average peak power (6.4%; p \u3c 0.001), maximum peak power (5.7%; p \u3c 0.001), average mean power (5.4%; p = 0.004), and maximum mean power (4.4%; p = 0.004) for all subjects combined. Compared to placebo, betaine ingestion significantly increased average peak power (3.4%; p = 0.026), maximum peak power max (3.8%; p = 0.007), average mean power (3.3%; p = 0.034), and maximum mean power (3.5%; p = 0.011) for all subjects combined. There were no differences between the placebo and baseline trials.Conclusions: One week of betaine ingestion improved cycling sprint power in recreationally active males and females. © 2012 Pryor et al; licensee BioMed Central Ltd

The Effect of Betaine on Nitrate and Cardiovascular Response to Exercise

International Journal of Exercise Science 10(4): 550-559, 2017. Betaine (BT) supplementation improves selected markers of physical performance, however, the mechanism(s) by which this change occurs remains largely unknown. Some speculate that BT may increase circulating nitrate concentrations, improving physical performance by augmentation of endothelial nitric oxide production. The purpose of this study was to investigate the effects of acute BT supplementation and exercise on plasma nitrate levels and related cardiovascular response (CVR). Placebo and BT trials were administered in a cross-over, randomized, double-blind, and counterbalanced fashion. Ten healthy college-aged volunteers consumed either a 250 ml placebo (carbohydrate-electrolyte beverage, CHO) or 250 ml CHO + 2.5 g BT. Subjects rested for 45 min, then cycled for 30 min at 60 rpm with a resistance of 2.5% body weight. Blood was drawn before and 45 min after BT supplementation, and immediately post exercise to assess plasma nitrate levels. Repeated measures ANOVA across treatments and times assessed differences in plasma nitrate and CVR variables with an alpha level set at 0.05. No significant interactions nor differences between groups were found for plasma nitrate levels or CVR variables with acute BT supplementation. A significant time effect (p \u3c 0.013) for all CVR variables was found and expected due to the effect of exercise. Acute BT supplementation did not increase plasma nitrate levels nor alter CVR at rest or during light to moderate cycling