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Older individuals fatigue more rapidly during, and recover more slowly from, dynamic exercise. Women are particularly vulnerable to these deleterious effects of aging, which increases their risk of falling. We have shown that dietary nitrate (NO3-), a source of nitric oxide (NO) via the NO3-→ nitrite (NO2-) → NO pathway, enhances muscle speed and power in older individuals in the non-fatigued state; however, it is unclear if it reduces fatigability and/or improves recoverability in this population. Using a double-blind, placebo-controlled, crossover design, we studied 18 older (age 70 ± 4 y) women who were administered an acute dose of beetroot juice (BRJ) containing either 15.6±3.6 or 3-. Blood samples were drawn throughout each ∼3 h visit for plasma NO3-and NO2-analysis. Peak torque was measured during, and periodically for 10 min after, 50 maximal knee extensions performed at 3.14 rad/s on an isokinetic dynamometer. Ingestion of NO3--containing BRJ increased plasma NO3-and NO2-concentrations by 21±8 and 4±4 fold, respectively. However, there were no differences in muscle fatigue or recovery. Dietary NO3-increases plasma NO3-and NO2-concentrations but does not reduce fatigability during or enhance recoverability after high intensity exercise in older women.

We sought to examine the effectiveness of an acute prolonged exercise session on post-exercise executive function in physically active adults and to assess if age or pre-exercise cognitive performance was predictive of the magnitude of change in executive task performance. Self-registered cyclists were recruited prior to participating in a 161-km mass-participation cycling event. Cyclists were excluded if they had not previously participated in a similar endurance event, were young (

We have recently demonstrated that dietary nitrate, a source of nitric oxide (NO) via the nitrate → nitrite → NO enterosalivary pathway, can improve muscle contractility in healthy older men and women. Nitrate ingestion has also been shown to reduce blood pressure in some, but not all, studies of older individuals. However, the optimal dose for eliciting these beneficial effects is unknown. A pilot randomized, double-blind, placebo-controlled crossover study was therefore performed to determine the effects of ingesting 3.3 mL/kg of concentrated beetroot juice containing 0, 200, or 400 µmol/kg of nitrate in 9 healthy older subjects (mean age 70 ± 1 years). Maximal knee extensor power (Pmax) and speed (Vmax) were measured ~2.5 hours after nitrate ingestion using isokinetic dynamometry. Blood pressure was monitored periodically throughout each study. Pmax (in W/kg) was higher (p < .05) after the lower dose (3.9 ± 0.4) compared to the placebo (3.7 ± 0.4) or higher dose (3.7 ± 0.4). Vmax (in rad/s) also tended to be higher (p = .08) after the lower dose (11.9 ± 0.7) compared to the placebo (10.8 ± 0.8) or higher dose (11.2 ± 0.8). Eight out of 9 subjects achieved a higher Pmax and Vmax after the lower versus the higher dose. These dose-related changes in muscle contractility generally paralleled changes in breath NO levels. No significant changes were found in systolic, diastolic, or mean arterial blood pressure. A lower dose of nitrate increases muscle speed and power in healthy older individuals, but these improvements are lost at a higher dose. Blood pressure, on the other hand, is not reduced even with a higher dose.

PurposeWe have recently demonstrated that dietary nitrate, a source of nitric oxide via the enterosalivary pathway, can improve muscle contractile function in healthy older men and women. Nitrate ingestion has also been shown to reduce blood pressure in some, but not all, studies of older individuals. However, the optimal dose for eliciting these beneficial effects is unknown.MethodsA randomized, double-blind, placebo-controlled crossover study was performed to determine the effects of ingesting 3.3 mL/kg of concentrated beetroot juice (BRJ) containing 0, 200, or 400 µmol/kg of nitrate in nine healthy older subjects (one man, eight women; mean age 70±1 y). Maximal knee extensor power (Pmax) and speed (Vmax) were measured 2 h after BRJ ingestion using isokinetic dynamometry. Blood pressure was monitored periodically throughout each study.ResultsPmax (in W/kg) was higher (P< 0.05) after the low dose (3.9±0.4) compared to the placebo (3.7±0.4) or high dose (3.7±0.4). Vmax (in rad/s) also tended higher (P = 0.08) in the low (11.9±0.7) compared to the placebo (10.8±0.8) or high dose (11.2±0.8) trials. Eight out of nine subjects achieved a higher Pmax and Vmax after the lower vs. the higher dose. These dose-related changes in muscle contractility paralleled changes in nitric oxide (NO) bioavailability, as reflected by changes in breath NO and plasma 3-nitrotyrosine levels. No significant changes were found in systolic, diastolic, or mean arterial pressure.ConclusionsVarying doses of dietary nitrate have differential effects on muscle function and blood pressure in older individuals. A moderate dose of nitrate increases muscle speed and power, but these improvements are lost at a higher dose. Blood pressure, on the other hand, is not reduced even with a higher dose.

BACKGROUND: Professional American-style football players are among the largest athletes across contemporary sporting disciplines, and weight gain during the years of football participation is common. At present, the health implications of this early-life weight gain remain incompletely understood. We sought to define weight trajectories of former professional American-style football athletes and to establish their relationship with 5 health afflictions common in this population (cardiovascular disease, cardiometabolic disease, neurocognitive impairment, sleep apnea, and chronic pain). METHODS: A comprehensive health survey was distributed to former National Football League (NFL) players. Former players reported body weight at 4 key time points (high school, college, professional, and time of survey response) as well as maximal retirement weight. Logistic regression was used to assess associations between weight gain during and after football participation with health affliction. RESULTS: In this cohort of former NFL players (n=3,506, age 53±14 years), mean total weight increase from high school to time of survey response was 40±36 pounds, with the majority of weight gain occurring during and not after football participation. The prevalence of self-reported health afflictions ranged from 9% for cardiovascular disease to 28% for chronic pain. Weight gain during periods of active football participation (high school to college and college to professional) was independently associated with risk of multiple later life health afflictions in models adjusted for football exposure, post-career lifestyle variables, and post-career weight gain. CONCLUSIONS: Early-life weight gain among American-style football athletes is common and is associated with risk of adverse health profiles during later-life. These findings establish football-associated weight gain as a key predictor of post-career health and raise important questions about the central role of targeted weight gain in this population.

Water is an essential nutrient for thermoregulation, metabolism, cognition, and overall physiological homeostatic function. However, aging adults display a blunted thirst mechanism and subsequently have an increased risk for dehydration or hyponatremia. Fluid consumption behaviors are modifiable and the importance of practicing adequate drinking behaviors for aging adults is amplified during exercise. Identification of aging adult’s hydration beliefs and how they attain hydration advice could provide valuable information into ways to promote better drinking habits to reduce fluid imbalances. Thus, this investigation evaluated the knowledge, beliefs and behaviors of middle-aged cyclists (MA) that were associated with hydration status and drinking behavior, before and during a 164-km mass-participation event (ambient temperature, 33.3±2.8oC(mean±SD)). Design: This cross-sectional field study retrospectively grouped participants by their second urine specific gravity (Usg) measurement of the event morning prior to a mass participation cycling event. Usg was assessed via handheld refractometer. The Hotter N’ Hell Hundred 164-km cycling event in Wichita Falls, Texas during the month of August. 36 male recreational cyclists (age, 53±9 y(mean±SD)). Participants were grouped according their urine specific gravity as either slightly hyperhydrated (SH; n=12, Usg≤1.014), euhydrated (EUH; n=12, Usg, 1.015-1.020), or slightly dehydrated (SD; n=12, Usg≥1.021). Exercise histories and questionnaires were recorded 24-48 h prior to the cycling event. Regardless of pre-event hydration status, all groups experienced a similar body mass loss during the 164-km event and finished with statistically similar exercise times; also, drinking behavior within all groups was influenced by multiple factors. The primary factors associated with MA cyclist drinking behavior were trial and error/personal history and thirst; further, the majority of cyclists (≥65%) in SH, EUH, and SD believed that dehydration affects performance negatively. The least important factors included rehydration recommendations from scientific and sports medicine organizations, plus information from sports drink manufacturers. Considering the complexity of the present findings and the physiological changes that accompany aging such as delayed thirst perception, we recommend that MA cyclists formulate an individualized drinking plan that is based on observations during exercise.

Individuals of all ages are encouraged to monitor their hydration status daily to prevent clinically severe fluid imbalances such as hyponatremia or dehydration. However, acute oral nutritional supplementation may alter urinary hydration assessments and potentially increase the likelihood of inappropriate clinical decisions or diagnosis. This investigation sought to examine the influence of three common over-the-counter nutritional supplements (beetroot, riboflavin, and Vitamin C) on urinary hydration assessments in physically active young men after a 2% exercise-induced dehydration.Eight males (Mean ± SD; age: 22 ± 3 yr; body mass index: 27 ± 5.0) consumed either a standard meal with supplementation (intervention) or a standard meal without supplementation (control). Participants performed a variety of aerobic or resistance exercises until reaching ≥2% body mass loss in a counter-balanced, double-blinded design. Following exercise participation, urine samples were collected for an 8 h observational period during which food consumption was replicated. Urine samples were analyzed for urine color, specific gravity, volume, and osmolality. Maintenance of ~2% body mass loss (2.6 ± 0.5%; range: 1.7-4.0%) was confirmed following the 8 h observational period.Statistically significant (p 0.05) changes were noted in urine color following Vitamin C supplementation compared to control; however, the difference was not clinically meaningful.These findings indicate that urine color, specific gravity, and osmolality maintain clinical utility to detect moderate levels of dehydration in physically active men consuming commercially available doses of beetroot, riboflavin, or Vitamin C.

Urine color (Ucol) as a hydration assessment tool provides practicality, ease of use, and correlates moderately to strongly with urine specific gravity (Usg) and urine osmolality (Uosm). Indicative of daily fluid turnover, along with solute and urochrome excretion in 24-hr samples, Ucol may also reflect dietary composition. Thus, the purpose of this investigation was to determine the efficacy of Ucol as a hydration status biomarker after nutritional supplementation with beetroot (880 mg), vitamin C (1000 mg), and riboflavin (200 mg). Twenty males (Mean ± SD; age, 21 ± 2 y; body mass, 82.12 ± 15.58 kg; height, 1.77 ± 0.06 m) consumed a standardized breakfast and collected all urine voids on one control day (CON) and 1 day after consuming a standardized breakfast and a randomized and double-blinded supplement (SUP) over 3 weeks. Participants replicated exercise and diet for one day before CON, and throughout CON and SUP. Ucol, Usg, Uosm, and urine volume were measured in all 24-hr samples, and Ucol and Usg were measured in all single samples. Ucol was a significant predictor of single sample Usg after all supplements (p < .05). Interestingly, 24-hr Ucol was not a significant predictor of 24-h Usg and Uosm after riboflavin supplementation (p = .20, p = .21). Further, there was a significant difference between CON and SUP 24-h Ucol only after riboflavin supplementation (p < .05). In conclusion, this investigation suggests that users of the UCC (urine color chart) should consider riboflavin supplementation when classifying hydration status and use a combination of urinary biomarkers (e.g., Usg and Ucol), both acutely and over 24 hr.

Context:To treat anterior cruciate ligament (ACL) injury, ACL reconstruction (ACLR) surgery is currently a standard of the care. However, effect of graft type including bone–patellar tendon–bone (BTB), hamstring tendon, or iliotibial band (ITB) on thigh size, knee range of motion (ROM), and muscle strength are understudied.Objective:To compare postoperative thigh circumference, knee ROM, and hip and thigh muscle strength in adolescent males who underwent ACLR, based on the 3 different autograft types: BTB, hamstring (HS), and ITB.Setting:Biomechanical laboratory.Participants:Male ACLR patients who are younger than 22 years of age (total N = 164).Intervention:At 6- to 9-month postoperative visits, thigh circumference, knee ROM, and hip and thigh muscle strength were measured.Main Outcome Measures:Deficits of each variable between the uninvolved and ACLR limb were compared for pediatric and adolescent ACLR males in the BTB, HS, and ITB cohorts. Baseline characteristics, including physical demographics and meniscus tear status, were compared, and differences identified were treated as covariates and incorporated in analysis of covariance.Results:Data were from 164 adolescent male ACLR patients [mean age 15.7 (1.2) years]. There were no statistical differences in thigh circumference, knee ROM, hip abductor, and hip-extensor strength among the 3 autografts. However, patients with BTB demonstrated 12.2% deficits in quadriceps strength compared with 0.5% surplus in HS patients (P = .002) and 1.2% deficits in ITB patients (P = .03). Patients with HS showed 31.7% deficits in hamstring strength compared with 5.4% deficits in BTB (P = .001) and 7.7% deficits in ITB (P = .001) groups at 6- to 9-month postoperative visits.Conclusion:Adolescent male ACLR patients with BTB and HS autografts demonstrated significant deficits in quadriceps and hamstring strength, respectively, at 6 to 9 months postoperatively. Minimal lower-extremity strength deficits were demonstrated in pediatric male ACLR patients undergoing ITB harvest.