Effects of Three Modest Levels of Proximal Loading on Marathon Pace Running Economy

International Journal of Exercise Science 13(7): 1120-1131, 2020. This study examined the effect of modest increases in proximal body mass on running economy expressed as metabolic cost (MC). External loads of 1.6 (L), 2.4 (M), and 3.2 kg (H) were added to the anterior and posterior torso region of male (n = 18) and female (n = 18) runners using a double-layered compression garment with gel inserts. MC was evaluated using stoichiometry equations of data collected via indirect calorimetry. Data was collected during four, 5-min running bouts at marathon pace for the 3 load levels and an unloaded state (CON). When data from both sexes were combined, MC for CON (13.2 ± 2.7) was lower (p \u3c 0.05) versus L (13.5 ± 2.6), M (13.6 ± 2.6), and H (13.7 ± 2.6 kcal/min), but L did not differ from CON when data was analyzed for each sex. Male runners exhibited stepped increases in MC across loads and a weak-moderate relationship (r = 0.37; p \u3c 0.01) between percentage change in absolute MC and increased percent body mass. A prediction model for MC (∆% kcal/min = 0.98(∆% body mass) – 0.91; SEE = ± 2.5%) was developed. For female runners, L increased MC by ~3.5% above CON, but no differentiation was found among L, M, and H, limiting the development of a prediction equation for females. Modest increases in body mass can produce detectable and potentially important levels of running economy impairment, but the relationship between changes in body mass and RE are complex, particularly in regards to sex

Predictors of Performance during a 161 km Mountain Footrace

Training volume and cardiovascular dynamics influence endurance performance. However, there is limited information on the interplay between training volume, cardiovascular dynamics, and performance in ultra-marathon athletes. PURPOSE: We aimed to determine predictors of performance in finishers of the 2023 Western States Endurance Run (WSER). METHODS: Sixty participants who finished the race (49 males/11 females; mean age: 44.7 ± 9.6 y, range: 26–66 y; BMI: 22.7 ± 2.2 kg/m2) completed pre-race surveys including average training volume (AV) and peak training volume (PV), as well as resting cardiovascular measures including resting heart rate (RHR) and augmentation index (AIx), a measure of wave reflection characteristics. Based on WSER completion time, we calculated average running velocity (RV). We assessed associations among 22 variables using bivariate correlation analysis (Pearson’s Correlation for normally distributed data and Spearman’s Rank Correlation if normality was not met). Within our listed variables, normality was met in age and AV. Additionally, we completed multiple regression analyses for predictors. We present descriptive data as mean ± SD. RESULTS: Participants had an average RV of 6.33 ± 0.97 km/h (3.93 ± 0.6 mph), and reported an AV of 91.9 ± 24.5 km/wk (57.1 ± 15.2 miles/wk) and a PV of 141.0 ± 47.2 km/wk (87.6 ± 29.3 miles/wk). We observed significant associations between RV and age (r(58) = -0.57, p r(58) = 0.41, p r(58) = 0.34, p R2 = 0.37; F(3,56) = 12.4, pb1 = 0.013; t(56) = 2.57, p = 0.013), resulting in a 0.33 km/h increase in RV for every 25-km increase in AV. Last, significant relations existed between RV and AIx (r(58) = -0.30, p = 0.022); and RHR (r(58) = -0.26, p = 0.046). CONCLUSION: We found that (1) average weekly training volume is a significant predictor of performance in elite ultra-marathon athletes and (2) race performance was inversely associated with resting arterial wave reflection characteristics and heart rate

ASSOCIATION BETWEEN CARDIORESPIRATORY FITNESS AND PHYSICAL ACTIVITY WITH SLEEP METRICS IN APPARENTLY HEALTHY ADULTS

BACKGROUND: High cardiorespiratory fitness (CRF), healthy physical activity (e.g., taking \u3e10,000 steps per day) and sleep habits (e.g., sleeping 7-9 hours per night) decrease the risk of all cause mortality. However, the association between CRF and physical activity with sleep are understudied and inconclusive. Thus, we sought to examine the associations between CRF and physical activity with objective and subjective sleep metrics. METHODS: Thirty-two adults (14 female, age 40 ± 18 years, body mass index [BMI] 25.8 ± 6.2 kg/m2) participated in this study. We assessed CRF using a graded treadmill exercise test to volitional exhaustion to determine relative VO2peak (mL/kg/min). We assessed physical activity using waist worn ActiGraph GT3X accelerometers for a minimum of 5-days (11.8 ± 3.6 days) to obtain average daily steps and moderate and vigorous physical activity (MVPA). Participants’ self-reported sleep quality was assessed using the Pittsburg Sleep Quality Index (PSQI) scored 0 [better] to 21 [worse]. Objective nightly sleep duration (hours) and efficiency (% of time in bed spent sleeping) were measured using Phillips Actiwatch Spectrum PLUS accelerometers (worn on the wrist) for a minimum of 5-days (7.1± 0.5 days days). All variables were tested for normality using the Shapiro Wilk test. We used Pearson’s r and Spearman’s rho correlations controlled for age, sex and BMI to examine associations between CRF and physical activity with sleep quality variables. Significance was set as p ≤ 0.05. RESULTS: After controlling for age, sex and BMI there was an association between VO2peak and sleep duration (r = 0.428, p = 0.021), but not PSQI (rho = -0.202, p = 0.313), or sleep efficiency (r = 0.168, p = 0.384). MVPA was not associated with PSQI (rho = -0.207, p = 0.395), sleep duration (r = 0.301, p = 0.185), or sleep efficiency (r = 0.222, p = 0.333). Steps were also not associated with PSQI (rho = -0.230, p = 0.344), sleep duration (r = 0.298, p = 0.189), or sleep efficiency (r = 0.258, p = 0.258). CONCLUSIONS: Our preliminary data indicate there is an association between cardiorespiratory fitness and objectively measured sleep duration, but not sleep efficiency, or subjective sleep quality. Physical activity was not associated with sleep. Additional data are needed to determine directionality between cardiorespiratory fitness, sleep duration, and potential mechanisms

Validity of heart rate derived core temperature estimation during simulated firefighting tasks

Abstract Rectal core temperature monitoring can help fire services mitigate heat injury but can be invasive and impractical. EQ02 + LifeMonitor provides a non-invasive estimation of core temperature. Therefore, the primary purpose of this study was to determine the validity of the EQ02 + LifeMonitor compared to the gold standard rectal thermometer core temperature assessment, as well as the potential influence of turnout gear on the estimated and physiological strain experienced during these activities. Thirteen participants completed simulated firefighting tasks with and without turnout gear, involving four rounds of a 5-min walk on a treadmill at 2.8 mph/2.5% grade and 20 deadlifts over 5 min in an environmental chamber set to 40.6 °C; 50% humidity. During each trial participants wore both an EQ02 + LifeMonitor and DataTherm II rectal thermometer. The results from the devices were statistically equivalent (p  0.372]. These results suggest the EQ02 + LifeMonitor may be a viable, non-invasive alternative for assessing core temperature compared to rectal temperature monitoring, especially during rigorous, intermittent activities. Turnout gear does however increase heart rate, cumulative core temperature, and perceived exertion. Additionally, the validity of the estimated core temperature is not impacted by the use turnout gear. This is likely due to significant changes in heart rate, which allowed the heart-rate derived estimate of core temperature to remain consistent with changes in DataTherm II rectal temperatures

AGE AND PHYSICAL ACTIVITY DO NOT IMPACT CIRCULATING SOLUBLE CD14 CONCENTRATION IN APPARENTLY HEALTHY ADULTS

BACKGROUND: Soluble CD14 (sCD14) (cluster of differentiation 14) is a co-receptor of bacterial lipopolysaccharide that is released from monocytes upon activation. There is a well-recognized role of sCD14 in inflammation, and aging has been associated with increased inflammation and cardiometabolic health risk factors (e.g., high blood pressure [BP], hyperglycemia). However, there is limited information on the combined influence of aging and physical activity on circulating sCD14. Therefore, the purpose of this study was to examine the influence of aging on plasma sCD14 concentration and the potential influence of physical activity. METHODS: Twenty young (11 females, age 22.7± 2.6, body mass index 26.7 ± 3.3, BP 119/73 ± 7/8 mmHg) and 21 old (11 female, age 58.4 ± 7.4, body mass index 27.8 ± 4.8, BP 125/76 ± 12/8 mmHg) adults participated in the study. Physical activity (PA) was assessed using waist worn ActiGraph GT3X accelerometers for a minimum of 5-days (7.6 ± 1.6 days) to obtain average daily steps, sedentary time, and moderate and vigorous PA (MVPA). We measured brachial BP using a SpyghmoCor XCEL after 10-minutes of supine rest. We assessed plasma concentrations of sCD14 using an enzyme-linked immunosorbent assay kit. Normality was assessed using Shapiro-Wilk. Students’ T Test or Mann Whitney test were used to make age comparisons between young (\u3c35 years) and older (\u3e45 years) adults. Pearson’s correlation and Spearman’s rho, controlled for age, body mass index, and sex, were used to assess relations between MVPA and steps with sCD14. Statistical significance was set as p ≤ 0.05 RESULTS: There was not a difference between young and older adults in circulating sCD14 concentration (young: 2348 ± 441 vs. older: 2487 ± 541 pg/ml, p = 0.501). There was not a difference between young and older adults in MVPA (young: 47 ± 25 vs. older: 48 ± 24 min/day, p = 0.873) or average daily steps (young: 7179 ± 3171 vs. older: 7797 ± 3595 steps/day, p = 0.679). There were not associations between sCD14 and daily MVPA (r = -0.176, p = 0.343) or Steps (rho = -0.278, p = 0.130). CONCLUSION: Our preliminary data indicate that there were no age differences in circulating sCD14 and no associations between habitual physical activity and circulating sCD14

AGE AND PHYSICAL ACTIVITY DOES NOT IMPACT LIPOPOLYSACCHARIDE-BINDING PROTEIN CONCENTRATION IN APPARENTLY HEALTHY ADULTS

BACKGROUND: LBP (lipopolysaccharide‐binding protein) is an acute‐phase protein that binds lipopolysaccharide in the blood and plays a role in subsequent activation of immune cells through the production of proinflammatory cytokines. LBP is associated with future cardiovascular disease in middle-aged and older adults. However, there is limited information on the combined influence of aging and physical activity on circulating LBP. Therefore, the purpose of this study was to examine the influence of aging on plasma LBP concentration and the potential influence of physical activity. METHODS: Ten young (4 females, age 23.5 ± 2.2, body mass index 26.3 ± 2.5 blood pressure 120/74 ± 8/8 mmHg) and 11 old (4 female, age 60.7 ± 5.5, body mass index 27.2 ± 3.2, blood pressure 124/74 ± 12/6 mmHg) participated in the study. Physical activity (PA) was assessed using waist worn ActiGraph GT3X accelerometers for a minimum of 6-days (7.1 ± 0.5 days) to obtain average daily steps, sedentary time, and moderate and vigorous PA (MVPA). We measured brachial blood pressure using a SpyghmoCor XCEL after 10-minutes of supine rest. We assessed plasma concentrations of LBP using an enzyme-linked immunosorbent assay kit. Normality was assessed using Shapiro-Wilk. Students’ T Test or Mann Whitney test were used to make age comparisons between young (\u3c35 years) and older (\u3e45 years) adults. Pearson’s correlation, controlled for age, body mass index, and sex, was used to assess relations between MVPA and steps with LBP. Statistical significance was set as p ≤ 0.05 RESULTS: There was not a difference between young and older adults in circulating LBP concentration (young: 8045 ± 3222 vs. older: 8905 ± 7087 pg/ml, p = 0.605). There was not a difference between young and older adults in MVPA (young: 56 ± 30 vs. older: 51 ± 28 min/day, p = 0.748) or average daily steps (young: 8150 ± 4315 vs. older: 8358 ± 4158 steps/day, p = 0.921). There were not associations between LBP and daily MVPA (r = -0.188, p = 0.519) or Steps (r = -0.267, p = 0.356). CONCLUSION: Our preliminary data indicate that there were no age differences in circulating LBP and no associations between habitual physical activity and circulating LBP

AGE-RELATED CARDIOVASCULAR HEALTH AMONG ELITE ULTRA-ENDURANCE ATHLETES

BACKGROUND: Aging is associated with increased cardiovascular (CV) disease risk which is partly attributable to increased blood pressure (BP) and central arterial stiffness. Regular exercise is recommended to slow CV aging, but it is unclear whether “extreme exercise”, such as ultra-endurance running (\u3e42.2 km), elicits the same CV benefits as lower-volume training. Therefore, the purpose of this investigation was to test the hypothesis that ultra-endurance running preserves CV health across the lifespan. METHODS: We measured supine BP with an automated brachial cuff and arterial stiffness (carotid-to-femoral pulse wave velocity [cfPWV]) with applanation tonometry (SphygmoCor XCEL, AtCor Medical) among 72 athletes (16F/56M; BMI: 22.6 ± 1.8 kg/m2) 1-3 days before they competed in the 161-km Western States Endurance Race (WSER) (Olympic Valley, CA; elevation: 1890 m). We present data as mean ± SD and confirmed normality using Shapiro-Wilk tests (α ≥ 0.05). We used simple linear regression to assess the relationship between age and systolic BP (SBP), diastolic BP (DBP), and cfPWV. We compared individual cfPWV outcomes to available normative data. RESULTS: Among 72 WSER athletes, age (46 ± 10 years; range: 26-69 yrs), SBP (129 ± 9 mmHg), DBP (78 ± 7 mmHg), and cfPWV (n = 70; 6.5 ± 1.0 m/s) were normally distributed (Ws ≥ 0.97, Ps ≥ 0.06). Approximately 60% (43/72) of the athletes presented with hypertension (≥130mmHg SBP and/or \u3e80 mmHg DBP) but age was not associated with SBP (R2 = 0.02, P = 0.23) or DBP (R2 = 0.05, P = 0.06). Age was positively associated with cfPWV (R2 = 0.25, P \u3c 0.001) but 84% (59/70) of participants had cfPWV values below their age-predicted value (mean difference: -0.9 m/s). CONCLUSIONS: Among these WSER athletes, a majority were hypertensive, but there was not a meaningful relationship between age and BP. Moreover, in this sample, the increase in SBP per decade (1.3 mmHg/decade) was much lower compared to previously reported increases among the general population (6.5 mmHg/decade). Despite an age-related increase in cfPWV, 84% of athletes had cfPWV values below their age-predicted value. These findings suggest that ultra-endurance training is associated with preserved CV health across the lifespan via attenuated age-related increases in BP and cfPWV values below age-predicted norms

Acute beetroot juice reduces blood pressure in young Black and White males but not females

A complex interplay of social, lifestyle, and physiological factors contribute to Black Americans having the highest blood pressure (BP) in America. One potential contributor to Black adult's higher BP may be reduced nitric oxide (NO) bioavailability. Therefore, we sought to determine whether augmenting NO bioavailability with acute beetroot juice (BRJ) supplementation would reduce resting BP and cardiovascular reactivity in Black and White adults, but to a greater extent in Black adults. A total of 18 Black and 20 White (∼equal split by biological sex) young adults completed this randomized, placebo-controlled (nitrate (NO3−)-depleted BRJ), crossover design study. We measured heart rate, brachial and central BP, and arterial stiffness (via pulse wave velocity) at rest, during handgrip exercise, and during post-exercise circulatory occlusion. Compared with White adults, Black adults exhibited higher pre-supplementation resting brachial and central BP (Ps ≤ 0.035; e.g., brachial systolic BP: 116(11) vs. 121(7) mmHg, P = 0.023). Compared with placebo, BRJ (∼12.8 mmol NO3−) reduced resting brachial systolic BP similarly in Black (Δ-4±10 mmHg) and White (Δ-4±7 mmHg) adults (P = 0.029). However, BRJ supplementation reduced BP in males (Ps ≤ 0.020) but not females (Ps ≥ 0.299). Irrespective of race or sex, increases in plasma NO3− were associated with reduced brachial systolic BP (ρ = −0.237, P = 0.042). No other treatment effects were observed for BP or arterial stiffness at rest or during physical stress (i.e., reactivity); Ps ≥ 0.075. Despite young Black adults having higher resting BP, acute BRJ supplementation reduced systolic BP in young Black and White adults by a similar magnitude, an effect that was driven by males

The crystal structure of 1-(2-iodo­benzo­yl)-4-(pyrimidin-2-yl)piperazine: a three-dimensional hydrogen-bonded framework, augmented by π–π stacking inter­actions and I⋯N halogen bonds

In 1-(2-iodo­benzo­yl)-4-(pyrimidin-2-yl)piperazine, C15H15IN4O, the central piperazine ring adopts an almost perfect chair conformation with the pyrimidine substituent in an equatorial site. The planar amide unit makes a dihedral angle of 80.44 (7)° with the phenyl ring. A combination of C—H⋯O and C—H⋯π(arene) hydrogen bonds links the mol­ecules into a complex three-dimensional network structure, augmented by a π–π stacking inter­action and an I⋯N halogen bond, all involving different pairs of inversion-related mol­ecules. Comparisons are made with the structures of a number of related compounds