Brachial Artery FMD and Endothelial Responses to High-Intensity Interval and Steady-State Moderate-Intensity Exercise

Brachial artery flow-mediated dilation (FMD) is a nitric oxide-dependent measure of conduit artery endothelial function that is potentiated by moderate- and high-intensity steady state exercise (SSE) for up to an hour after exercise; however, it is unclear whether high-intensity interval exercise (HIIE) provides a longer-lasting stimulus for enhancing FMD or greater oxidative and nitrative stress on the vascular endothelium than a comparable or greater amount of SSE. PURPOSE: Determine the influence of HIIE on post-exercise brachial artery FMD and the relationship between FMD and markers of endothelial function relative to a comparable amount of moderate-intensity SSE and a dose that is half that of SSE. METHODS: Seventeen male participants (age 27.8 + 6.4 yr; weight 80.6 + 9.0 kg; BMI 25.1 + 2.4 kg/m2; VO2max 52.1 + 7.5 ml/kg/min) underwent HIIE by treadmill running (90% and 40% of VO2reserve in 3:2 min ratio) to expend 500 kcals; HIIE to expend 250 kcals, and; SSE at 70% VO2reserve to expend 500 kcals in a randomized crossover design. All exercise conditions averaged 70% VO2reserve. Ultrasound measurements of brachial artery FMD and blood measures of total antioxidant capacity (TAC) in copper reducing equivalents, apolipoprotein A-1 (ApoA1: g/L), PON1 concentration (PON1c: mg/mL), arylesterase activity (PON1a: kU/L), soluble vascular adhesion molecule-1 (sVCAM-1: ng/mL) and nitrotyrosine (NT: nM) were obtained just before and 2 hr after exercise. FMD responses to exercise were analyzed using 3 (condition) by 2 (sample point) repeated measures ANOVAs. Pearson product-moment correlations of change variables (2 hr post-exercise – pre-exercise values) were calculated to determine relationships between FMD responses and blood variable responses to exercise. RESULTS: Brachial artery FMD responses were unaltered 2 hr after exercise in all three conditions (p \u3e 0.05). FMD responses were correlated with changes in PON1c (r = 0.221, p \u3c 0.0001) and inversely with changes TAC (r = -0.170, p \u3c 0.0001). Changes in s-VCAM1 were correlated with change in NT (r = 0.423, p \u3c 0.0001) and inversely with changes in PON1c (r = -0.177, p \u3c 0.0001). SUMMARY: Brachial artery FMD is unaltered 2 hr after HIIE or SSE of moderate duration in young fit men and does not appear to be related to responses in other markers of endothelial function

High-Density Lipoprotein Antioxidant Responses to High-Intensity Interval and Steady-State Moderate-Intensity Exercise

High-intensity interval exercise (HIIE) may impart health benefits beyond what is acquired through moderate-intensity steady state exercise (SSE). Paraoxonase 1 (PON1), an antioxidant associated with high-density lipoprotein (HDL), may be altered with exercise; however, it is unclear whether HIIE provides a greater stimulus for increasing PON1 antioxidant activity than a comparable or greater amount of SSE. PURPOSE: Determine the influence of HIIE on PON1 concentration and activity relative to a comparable amount of moderate-intensity SSE and a dose that is half that of SSE. METHODS: Seventeen male participants (age 27.8 + 6.4 yr; weight 80.6 + 9.0 kg; BMI 25.1 + 2.4 kg/m2; %fat = 19 + 5; VO2max 52.1 + 7.5 ml/kg/min) underwent HIIE by treadmill running (90% and 40% of VO2reserve in 3:2 min ratio) to expend 500 kcals (H500); HIIE to expend 250 kcals (H250), and; SSE at 70% VO2reserve to expend 500 kcals (M500) in a randomized crossover design. Intensities of all exercise conditions averaged 70% VO2reserve. Blood measures of total antioxidant capacity (TAC) in copper reducing equivalents, HDL (g/mL), apolipoprotein A-1 (ApoA1: g/L), PON1 concentration (PON1c: g/mL) and arylesterase activity (PON1a: kU/L) were obtained just before, immediately after, 2 hr and 24 hr after exercise. Significant differences were determined using 3 by 4 repeated measures ANOVAs. Effect sizes were calculated to determine the magnitude of dependent variable responses to exercise. RESULTS: Pre-exercise HDL concentration was lower in H250 and increased most in H250 versus other exercise conditions (p \u3c 0.001, ES = 0.83). Other antioxidant responses were similar across exercise conditions. ApoA1 (+ 8.0%) and PON1a (+ 9.3%) increased immediately after exercise and remained elevated 24 hr after exercise (p \u3c 0.0001 for each; ApoA1 ES = 0.85, PON1a ES = 0.57). PON1c was increased 2.4% above baseline at 2 hr post-exercise (p = 0.0296, ES = 0.18) and TAC was elevated 8.6% above baseline at 24 hr post-exercise (p = 0.0227, ES = 0.48). SUMMARY: HDL and HDL antioxidant properties are transiently potentiated by HIIE with as little as 250 kcals of energy expenditure. HDL antioxidant activity and total antioxidant capacity are elevated with HIIE and SSE of moderate intensity in a similar manner and are observed for up to 24 hr after exercise

Variation in Individual Responses to Time-Restricted Feeding and Resistance Training

Time-restricted feeding (TRF) is a form of intermittent fasting which limits all caloric intake to a certain period of time each day in an attempt to reduce daily energy intake, promote weight loss, and improve health. Resistance training (RT) has been reported to increase muscular strength and improve body composition. Very limited information is available on the combination of TRF and RT. The purpose of this study was to examine the variation in individual body composition, dietary intake, and muscular performance responses to an 8-wk TRF and RT program. Healthy males (n = 20; age = 22 ± 3 y; BMI = 27 ± 6 kg/m2; % fat = 22 ± 6 % wt) were randomized to TRF + RT or RT alone for 8 wks. RT was performed 3 dys/wk and consisted of alternate workouts of upper and lower body using a resistance progression scheme. TRF limited energy intake to a 4-hr period on the 4 dys/wk when RT was not performed. Energy intake was not restricted in either group, and eating times were not specified in the RT alone group. Body composition, muscular performance, and dietary records were assessed at 0, 4, and 8 wks. Inter- and intra-individual variations in outcome measures were estimated by hierarchical linear growth modeling. The amount of variability attributable to characteristics between or within participants was evaluated from variance estimates. For TRF + RT, percent changes ranged from -5.5 to +2.6% for body weight, -22.1 to +9.4% for fat mass, -7.7 to +4.6% for lean body mass, +3.4 to +30.4% for bench press 1-RM, and +10.1 to +67.6% for leg press 1-RM. For RT alone, percent changes ranged from -6.6 to +2.1% for body weight, -14.4 to +12.6% for fat mass, -4.1 to +3.9% for lean body mass, +4.9 to +12.9% for bench press 1-RM, and +14.3 to +37.7% for leg press 1-RM. Percentages of total variability attributed to inter-individual factors ranged from 3.3 to 49.2% for dietary measures, 59.0 to 93.9% for muscular performance, and 97.0 to 99.6% for body composition. Remaining variability was attributed to intra-individual factors. Individual responses to the study interventions varied widely. Differences between individuals were an important source of variability, indicating participant samples should be homogenous and/or quite large to examine changes in body composition or muscular performance using nutrition and exercise interventions

3-Nitrotyrosine and Soluble Vascular and Intracellular Adhesion Molecule Responses to High-Intensity Interval and Steady-State Moderate-Intensity Exercise

Vascular endothelium may respond differently to high-intensity interval exercise (HIIE) when compared to moderate-intensity steady state exercise (SSE). We hypothesized that greater sympathetic stimulation of soluble vascular adhesion molecule-1 (sVCAM-1) and intracellular adhesion molecule-1 (sICAM-1) and greater oxidative and nitrative stress on the vascular endothelium may transiently result from HIIE. PURPOSE: Determine the influence of HIIE on sVCAM-1, sICAM-1 and 3-nitrotyrosine (NT), a marker of nitric oxide-dependent reactive nitrogen species and nitrative stress, relative to a comparable amount of moderate-intensity SSE and a dose that is half that of SSE. METHODS: Seventeen male participants (age 27.8 + 6.4 yr; weight 80.6 + 9.0 kg; BMI 25.1 + 2.4 kg/m2; %fat = 19 + 5; VO2max 52.1 + 7.5 ml/kg/min) underwent HIIE by treadmill running (90% and 40% of VO2reserve in 3:2 min ratio) to expend 500 kcals (H500); HIIE to expend 250 kcals (H250), and; SSE at 70% VO2reserve to expend 500 kcals (M500) in a randomized crossover design. Intensities of all exercise conditions averaged 70% VO2reserve. Blood measures of sVCAM-1 (ng/mL), sICAM-1 (ng/mL), NT (nM), epinephrine (EPI) and norepinephrine (NE) in pg/mL, were obtained just before, immediately after, 2 hr and 24 hr after exercise. Significant differences were determined using 3 by 4 repeated measures ANOVAs. Effect sizes were calculated to determine the magnitude of dependent variable responses to exercise. RESULTS: HIIE resulted in 2 to 2.5 fold greater EPI responses immediately after exercise versus SSE (p = 0.0059, H250 ES = 1.89; H500 ES = 3.04). NE increased an average of 5.4 times above pre-exercise values across all exercise conditions (p \u3c 0.0001). NT decreased immediately after HIIE (H250 ES = - 0.39; H500 ES = -0.97) and returned to baseline by 2 hr post-exercise; whereas, NT was elevated 111% 2 hr (ES = 2.46) and remained 24 hr after SSE (p = 0.0001). sVCAM-1 was unchanged with HIIE but increased 6% immediately following moderate-intensity SSE and remained elevated 24 hr post-exercise (p \u3c 0.0005, ES = 1.01). SUMMARY: Our results are in direct opposition to our hypothesis. Transient elevations in NT and sVCAM-1 after moderate-intensity SSE but not HIIE of similar average intensity and duration may indicate unique effects of interval exercise. NT and sVCAM-1 were not elevated after HIIE in spite of a greater sympathetic response than what was observed after moderate-intensity SSE

Cardiorespiratory and Biomechanical Changes with Hippotherapy in Children with and without Cerebral Palsy

Hippotherapy utilizes the rhythmic movement of the horse to improve functional abilities and quality of life of individuals with neurological impairments. Little is known regarding the changes in body segment kinematics and cardiovascular responses of the rider due to the therapy. A change in the magnitude of pelvic displacement (PD) may allow those who use the therapy to more easily perform activities of daily living. Also, reduced cardiovascular stress to similar physical activities may be an important, but overlooked, therapeutic benefit of hippotherapy. The purpose of this study was to characterize PD and cardiorespiratory (CR) responses to simulated horseback riding (SHR) and walking in children with minimal-to-moderate spastic cerebral palsy (CP) before and after eight weeks of hippotherapy. These results were compared to healthy children undergoing the same protocol. Our hypothesis was that eight weeks of hippotherapy would elicit an increase in PD and reduced CR response during SHR and treadmill walking in children with CP. Eight children with CP (1 female, 7 males; 10 + 4 years of age; height 54 + 10 in; weight 70.2 + 34.3 lb) and eight healthy children (5 females, 3 males; 11 + 2 years of age; height 59 + 6 in; weight 104.6 + 33.4 lb) underwent similar hippotherapy training. Before and after the intervention, both groups completed simulated horseback riding (SHR) at an intensity approximating a fast walk (0.65 Hz) and walked on a treadmill (1 mph, 0% grade). PD along the anterior-posterior, superior-inferior and medial-lateral axes and HR, VO2, VE, SBP, and DBP were measured at steady-state exercise. Mean arterial pressure and rate pressure product were calculated. Prior to hippotherapy, PD was increased in healthy children (p = 0.032) but CR responses were similar in both groups during SHR (p \u3e 0.05 for all). Treadmill walking elicited greater PD and CR responses compared to SHR in both groups and significantly greater responses in CP compared to healthy children (p \u3c 0.05 for all). Eight weeks of hippotherapy did not alter acute responses. Our findings demonstrate treadmill walking at 1 mph elicits greater PD and CR responses than SHR. The walking responses are more pronounced in children with CP compared to healthy children. Observable cardiovascular adaptations or kinematic changes in children with CP are unaffected by short-term hippotherapy training

The role of fetuin-A in disease processes prevalent in postmenopausal women

The purpose of this review is to summarize the role of fetuin-A in disease processes prevalent in postmenopausal women and synthesize effective interventions in obtaining healthy fetuin-A levels. A review of databases for articles related to fetuin-A and diseases associated with postmenopausal women was conducted. Articles were limited to full-text access, published in English since 1944. High fetuin-A levels are closely associated with decreased bone mineral density, increased cardiovascular disease risks, impairment of insulin signaling and disruption of adipocyte functioning. Postmenopausal women have increased risk of osteoporosis, cardiovascular disease, insulin-resistance, intra-abdominal fat accumulation and vascular calcification. Low-levels of fetuin-A have been shown to be protective against the latter. The role of fetuin-A is multi-factorial and the mechanisms in which it is involved in each of these processes are vast. The present body of literature is inconsistent in defining high versus low levels of fetuin-A and their association with healthy-matched controls. The diseases associated with high levels of fetuin-A mimic diseases most prevalent in postmenopausal women. In addition, there is no research, to date, exploring fetuin-A levels in postmenopausal women and the associations it may or may not have in related diseases.El propósito de esta revisión es sintetizar el papel de la fetuina A en los procesos de enfermedad prevalentes en mujeres posmenopáusicas y resumir las intervenciones efectivas que permiten obtener niveles saludables de fetuina A. Para ello, se revisaron bases de datos con artículos relacionados con fetuina A y las enfermedades asociadas con mujeres posmenopáusicas. La búsqueda de artículos se limitó a aquellos de texto completo publicados en el idioma inglés desde el año 1944. Se encontró que altos niveles de fetuina A están íntimamente relacionados con una reducción de la densidad mineral ósea, un aumento en el riesgo de enfermedad cardiovascular, deterioro de la señalización de la insulina y la alteración del funcionamiento de los adipocitos. Las mujeres posmenopáusicas tienen un mayor riesgo de osteoporosis, enfermedad cardiovascular, resistencia a la insulina, acumulación de grasa intra abdominal y calcificación vascular. Se ha demostrado que niveles bajos de fetuina A son protectores contra esta última condición. El papel de fetuina A es multifactorial y los mecanismos en los que está involucrado en cada uno de estos procesos son muy amplios. El estado actual de la literatura no es consistente en la definición de niveles de fetuina A altos versus bajos y su asociación con controles sanos. Las enfermedades asociadas con altos niveles de fetuina A asemejan las enfermedades más prevalentes en mujeres posmenopáusicas. Además, no existen investigaciones, hasta la fecha, en las que se exploren los niveles de fetuina A en mujeres posmenopáusicas y las asociaciones que puede o no puede tener en las enfermedades relacionadas

Exiting TANF: Individual and Local Factors and Their Differential Influence Across Racial Groups

We ask whether individual and local factors known to influence reliance on welfare continue to be important under the TANF program, and if such factors differentially affect exit from TANF for African Americans and whites. Copyright (c) 2006 by the Southwestern Social Science Association.