A Tutorial on Oxidative Stress and Redox Signaling with Application to Exercise and Sedentariness

Oxidative stress has been shown to play a role in the etiology of several chronic diseases, including cardiovascular disease, diabetes mellitus, and cancer. Free radicals and, most prominently, the superoxide radical, result from oxidative metabolism and several enzyme-catalyzed reactions, and endogenous cellular antioxidants dismutate many reactive oxygen species (ROS). Under certain conditions, ROS production can outpace dismutation (e.g., long-term sedentariness and positive energy balance) and the result is oxidative stress, with proteins, lipids, and DNA the most common targets of radicals. However, the molecules that contribute to oxidative stress also appear to participate in vital cell signaling activity that supports health and stimulates favorable adaptations to exercise training, such that inhibiting ROS formation prevents common adaptations to training. Furthermore, researchers have recently suggested that some proteins are not as readily formed when the redox state of the cell is insufficiently oxidative. Exercise training appears to optimize the redox environment by dramatically enhancing the capacity of the cell to neutralize ROS while regularly creating oxidative environments in which membrane and secretory proteins can be synthesized. The role that exercise plays in enhancing management of ROS likely explains many of the associated health benefits

Metabolic biomarkers following a short and long bout of high-intensity functional training in recreationally trained men

Glucose regulation is a fundamental process of metabolic function, and is acutely altered by physical activity. High-Intensity Functional Training (HIFT) is a form of exercise performed using combinations of various modalities and durations. It is unknown if the metabolic responses to HIFT are similar to more commonly studied modalities (e.g., cycling and treadmill exercise), or if exercise duration will influence glucose regulation. The purpose of this study was to determine the effect of a Short (0.05), except for lowered 3HR E (p=0.007). This study demonstrated that both SHORT and LONG bouts of HIFT elicited GLU, INS, E, and NE responses similar to those reported in response to high-intensity treadmill and cycling exercise, and that duration of the HIFT bouts may not be a determining factor in glucose regulation in healthy individuals

The effect of chronic quercetin supplementation on bone health in postmenopausal women: A double-blind placebo-controlled investigation

Currently, there is limited research investigating the effects of quercetin on bone turnover and density. Therefore, this study aimed to examine the efficacy of 90-day quercetin supplementation on bone turnover, inflammation, body composition, and physical function in postmenopausal women. Thirty-four healthy postmenopausal women (59.2 ± 7.0 yrs, 80.7 ± 15.6 kg, 29.8 ± 6.1 kg⸱m2) participated in the double-blind placebo-controlled investigation. Participants were randomly assigned to one of two groups: 500 mg of Q or 500 mg of fiber (placebo; PLB). Data collected during the pre-and post-supplementation assessments included: bone turnover (osteocalcin, P1NP, CTX), inflammation markers (IL-6, TNF-alpha, CRP), body composition, dominant handgrip strength, and timed up and go test. Independent samples t-tests were used for between-group comparisons of baseline values and the percent change for each dependent variable. A significant difference in percent change for osteocalcin (Q: 20.5±25.7; PLB: 1.3±17.2; p=0.016; d=0.89), P1NP (Q: 28.9 (6.0–57.3); PLB: 4.6 (-7.6 – 8.5); p=0.030; d=0.64), and CTX (Q: 39.0 (-10.0 – 84.6); PLB: -7.74 (-28.9 – 18.5); p=0.023; d=0.91) was found between Q and PLB, with greater increases in Q. Changes in the inflammation markers IL-6 (Q: -17.6±24.1; PLB: 2.90±31.1; p=0.045; d=0.73) and TNF-alpha (Q: -4.9± (-15.3 – [-3.2]); PLB: 1.9 (-7.8 – 4.0); p=0.021; d=0.90) between the two groups were significant. No significant changes were found between groups for CRP, body composition, and physical function (p\u3e0.05). The data suggest that Q may improve bone health status in postmenopausal women through its ability to decrease pro-inflammatory mediators and increase turnover markers

The Effect of Quercetin on Bone Turnover Markers, Inflammatory Markers, and Bone Mineral Density in Postmenopausal Women: A Double-Blind Placebo-Controlled Investigation

Maintaining optimal bone health prevents major bone disorders (e.g., osteoporosis) and prolongs longevity. Quercetin is a plant-based flavonoid that is suggested to have anti-inflammatory effects and may improve bone health. PURPOSE: To investigate the effects of quercetin supplementation over 90-days on prominent bone turnover markers (BTMs), inflammatory markers, bone mineral density (BMD), body composition, and physical functioning in postmenopausal women. METHODS: Thirty-three healthy, nonosteoporotic, postmenopausal women (59.2±7.0 years) participated in a double-blind, placebo-controlled investigation. Participants were randomized into one of two supplement groups: 1) 500 mg of quercetin (QUE) once daily or 2) 500 mg of methylcellulose (placebo; PLB) once daily. Pre- and post-testing visits included assessments of BTMs (i.e., osteocalcin [OC], procollagen type-I N-terminal propeptide [PINP], and type-I collagen cross-linked C-terminal telopeptide [CTX]), inflammatory markers (i.e., interleukin [IL]-6, tumor necrosis factor-alpha [TNF-a], and C-reactive protein [CRP]), BMD measurements, body composition measurements (i.e., body fat percentage), and physical function. RESULTS: The QUE group increased OC (p=0.016; d=0.89), PINP (p=0.030; d=0.64), and CTX (p=0.023; d=0.91) levels and decreased IL-6 (p=0.045; d=0.73) and TNF-a (p=0.021; d=0.90) levels compared to PLB. CRP (p=0.448; d=0.34), BMD, body composition, and physical function remained unchanged. CONCLUSION: The results indicate that QUE may maintain optimal bone health by mediating bone formation and decreasing pro-inflammatory cytokines

Carbohydrate Rinse Fails to Enhance Cycling Performance or Alter Metabolic and Autonomic Recovery in Recreational Cyclists

The purpose of the study was to examine the effects of carbohydrate (CHO) mouth rinsing on autonomic and metabolic recovery as well as cycling performance. Ten male recreational cyclists (age = 30 ± 6 years, VO2peak = 54.5 ± 8.1 mL·kg-1·min-1) completed a randomized, double-blind, placebo-controlled, crossover designed study. A CHO or a placebo (PLA) rinse was administered every 12.5% of a work to completion trial (75%Wmax). Heart rate variability (lnRMSSD), the respiratory exchange ratio, and plasma epinephrine, norepinephrine, insulin, glucose, free fatty acids (FFA), and lactate were measured pre- and post-exercise. The CHO rinse did not improve time to completion of the test trial (CHO: 4108 ± 307 s, PLA: 4176 ± 374 s, p = 0.545). Further, the CHO rinse did not impact autonomic recovery, as measured by lnRMSSD (p = 0.787) and epinephrine (p = 0.132). Metabolic biomarkers were also unaffected by the CHO rinse, with no differences observed in responses of FFA (p = 0.064), lactate (p = 0.302), glucose (p = 0.113) or insulin (p = 0.408). Therefore, the CHO mouth rinse does not reduce the acute sympathetic response following strenuous exercise and does not result in improvements in cycling time to completion

Selecting teachers and prospective teachers : a meta-analysis

The purpose of this review article was to examine the methods used for the selection of teachers for employment and prospective teachers entering initial teacher education (ITE) programs, and to assess the predictive validity of these methods. We reviewed 32 studies reporting selection methods administered in high-stakes conditions and that included an external (not self-reported) teacher effectiveness outcome measure. The overall effect size was small but significant (r = 0.12, p <.001). Moderator analyses showed that academic and non-academic predictors were both significantly associated with teacher effectiveness measures and that effect sizes were small (but significant) for selection into employment and ITE. We conclude the review by proposing a research agenda that has the potential to enhance educational outcomes by improving the selection of prospective teachers

Physiological Responses to Balance Walking

AIM: The aim of the study was to determine the effects of the use of walking poles and angle-soled shoes (i.e., Balance Walking), cumulatively, and independently, on the physiological responses to walking, and to determine the influence of velocity on those effects. METHODS: Twenty females and 5 males (22.36 ± 3.23 yr) exercised in 4 conditions – flat-soled shoes/no poles; angle-soled shoes/no poles; flat-soled shoes/with poles; angle-soled shoes/with poles) in random order. Each session consisted of walking for 3 min at 5 velocities (53.6, 67.0, 80.4, 93.8, and 107.2 m ∙ min-1 )while heart rate (HR) and oxygen uptake (VO2) were recorded. RESULTS: A significant main-effect for shoe-condition and pole-condition was found for HR and VO2 at all walking velocities. In addition, the influence of angle-soled shoes and walking poles was greater at faster velocities. CONCLUSION: The use of angle-soled shoes or walking poles independently increase the physiological responses to walking, with the combination of both (Balance Walking) being additive

Should Body Size Categories Be More Common in Endurance Running Events?

Thousands of endurance running events are held each year in the United States, and most of them use age and sex categories to account for documented effects of those factors on running performance. However, most running events do not provide categories of body mass, despite abundant evidence that it, too, dramatically influences endurance running performance. The purposes of this article are to (1) discuss how body mass affects endurance running performance, (2) explain several mechanisms through which body mass influences endurance running performance, and (3) suggest possible ways in which body mass might be categorized in endurance running events

Personalizing activity recommendations for individuals with type 2 diabetes

By reading this article, fitness professionals who work with novice exercisers with type 2 diabetes mellitus (T2DM) will be able to: individualize recommendations for activity timing, reducing sedentary time, and modes of exercise to maximize blood sugar control for clients with T2DM; summarize the benefits and limitations of step tracking on blood sugar control for individuals with T2DM