Plasticity of heart rate signalling and complexity with exercise training in obese individuals with and without type 2 diabetes.

Objective: To examine the responsiveness of cardiac autonomic function and baroreflex sensitivity (BRS) to exercise training in obese individuals without (OB) and with type 2 diabetes (ObT2D).

Design: Subjects were tested in the supine position and in response to a sympathetic challenge before and after a 16-week aerobic training program. All testing was conducted in the morning following a 12-h fast.

Spectral methods of heart rate variability analysis during dynamic exercise.

Objectives: To apply both autoregressive (AR) and fast Fourier transform (FFT) spectral analysis at rest, during two different dynamic exercise intensities and in recovery from maximal exercise and to compare raw and normalized powers obtained with both methods.

Methods: Sixteen participants (age 22.3 +/- 4.

Reliability of Wingate testing in adolescents with Down syndrome.

The Wingate anaerobic test (WAnT) has not been used to assess individuals with Down syndrome (DS) and it is unknown if it is reliable in this population. We investigated the reliability of the WAnT in 19 adolescents with DS (age = 14.8 yrs; weight = 52.

Resistance exercise training reduces central blood pressure and improves microvascular function in African American and white men.

Objective: African American men have stiffer large central arteries and impaired dilation of smaller peripheral arteries when compared to their white peers. The purpose of this study was to examine the effect of resistance exercise training (RT) on vascular function and central blood pressure (BP) in young (22 years) African American and white men.

Methods: Vascular and hemodynamic measures were made in 19 African American and 18 white men at baseline and following 6-weeks of RT.

Heart rate recovery after exercise and incidence of type 2 diabetes in men.

Objectives: We tested that slow heart rate recovery (HRR) after exercise testing, indicative of decreased parasympathetic nervous system activity, is associated with the development of type 2 diabetes in 1,813 healthy men.

Methods: Heart rate recovery was calculated as the difference between maximum heart rate during the exercise test and heart rate 1 min after cessation of the exercise test.

Results: During an average of 6.

Hemodynamic and vascular response to resistance exercise with L-arginine.

Purpose: L-arginine, the precursor to nitric oxide (NO), has been shown to improve endothelial function in patients with endothelial dysfunction. Resistance exercise has been shown to increase arterial stiffness acutely with no definitive cause. It is possible that a reduction in NO bioavailability is responsible for this.

The effect of acute aerobic and resistance exercise on working memory.

Purpose: The goal of this investigation was to assess the influence of acute bouts of aerobic versus resistance exercise on the executive control of working memory.

Methods: Twenty-one young adult participants completed a cardiorespiratory fitness test and maximal strength tests. On subsequent days, task performance measures of reaction time (RT) and accuracy were collected while participants completed a modified Sternberg working memory task before the start of, immediately after, and 30 min after an intervention consisting of 30 min of either resistance or aerobic exercise and a seated rest control.

Influence of arterial wave reflection on carotid blood pressure and intima-media thickness in older endurance trained men and women with pre-hypertension.

Increased carotid intima-media thickness (IMT) with aging is a significant predictor of mortality. Older endurance trained (ET) individuals have lower carotid artery stiffness but similar carotid IMT when compared to sedentary (SED) age-matched peers. The purpose of this study was to examine the contribution of arterial wave reflections to carotid hemodynamics and IMT in older ET and SED with pre-hypertension.

Catecholamine response to maximal exercise in persons with Down syndrome.

Individuals with Down syndrome (DS) exhibit low peak aerobic capacities and heart rates. Although autonomic modulation is attenuated in individuals with DS at rest, the exercise response appears normal. This suggests that mechanisms other than autonomic control influence the low aerobic capacity, such as catecholamine responsiveness to exercise.

Carotid artery stiffness, high-density lipoprotein cholesterol and inflammation in men with pre-hypertension.

Low circulating levels of high-density lipoprotein cholesterol (HDL-C) are associated with increased risk for cardiovascular events. HDL-C has a variety of poorly understood atheroprotective effects, including altering lipid metabolism and reducing inflammation. Increased arterial stiffness is an important predictor of subsequent cardiovascular risk.

Aerobic cost in elite female adolescent swimmers.

Maximal performance in swimming depends on metabolic power and the economy of swimming. Thus, the energy cost of swimming (economy= VO(2)/V, C(s)) and maximal aerobic power (VO(2max)) in elite young female swimmers (n=10, age: 15.3+/-1.

C-reactive protein and cardiac vagal activity following resistance exercise training in young African-American and white men.

African Americans have a greater prevalence of hypertension and diabetes compared with white Americans, and both autonomic dysregulation and inflammation have been implicated in the etiology of these disease states. The purpose of this study was to examine the cardiac autonomic and systemic inflammatory response to resistance training in young African-American and white men. Linear (time and frequency domain) and nonlinear (sample entropy) heart rate variability, baroreflex sensitivity, tonic and reflex vagal activity, and postexercise heart rate recovery were used to assess cardiac vagal modulation.

Complexity of force output during static exercise in individuals with Down syndrome.

Force variability is greater in individuals with Down syndrome (DS) compared with persons without DS and is similar to that seen with normal aging. The purpose of this study was to examine the structure (in both time and frequency domains) of force output variability in persons with DS to determine whether deficits in force control are similar between individuals with DS and older adults. An isometric handgrip task at a constant force (30% of maximal voluntary contraction) was completed by individuals with DS (n = 29, age 26 yr), and healthy young (n = 26, age 27 yr) and older (n = 33, age 70 yr) individuals.

Association between moderate physical activity, spinal motion and back muscle strength in postmenopausal women with and without osteoporosis.

Objective: The purpose of this study was to determine whether physical activity levels of postmenopausal women were associated with their bone mineral density (BMD), back extensor strength (BES), severity of thoracic kyphosis and range of spinal motion.

Method: This study adopted a cross-sectional design. 189 female subjects from 50 to 80 years of age were divided into moderately active (n=63) and sedentary (n=126) groups according to their physical activity level, which is measured by the physical activity score.

Hemodynamic responses and linear and non-linear dynamics of cardiovascular autonomic regulation following supramaximal exercise.

The purpose of this study was to examine hemodynamic responses and cardiovascular autonomic regulation following supramaximal exercise. Electrocardiographic R-R intervals and beat-to-beat hemodynamics were recorded before and for 10 min after a 30-s Wingate test in 11 males. Spectral analysis of heart rate (HR) and arterial pressure variability, analysis of HR complexity, the sequence technique and the cross-spectral transfer function were used to quantify autonomic regulation and baroreflex sensitivity.

Walking economy in male adults with Down syndrome.

The purpose of this study was to investigate walking economy in response to steady-state locomotion in adult males with Down syndrome (DS) and in healthy controls. Twelve participants with DS (34.5 +/- 7.

Racial differences in central blood pressure and vascular function in young men.

Young African-American men have altered macrovascular and microvascular function. In this cross-sectional study, we tested the hypothesis that vascular dysfunction in young African-American men would contribute to greater central blood pressure (BP) compared with young white men. Fifty-five young (23 yr), healthy men (25 African-American and 30 white) underwent measures of vascular structure and function, including carotid artery intima-media thickness (IMT) and carotid artery beta-stiffness via ultrasonography, aortic pulse wave velocity, aortic augmentation index (AIx), and wave reflection travel time (Tr) via radial artery tonometery and a generalized transfer function, and microvascular vasodilatory capacity of forearm resistance arteries with strain-gauge plethysmography.

Age-related changes in aerobic capacity in individuals with mental retardation: a 20-yr review.

Introduction: Persons with mental retardation (MR), particularly individuals with Down syndrome (DS), have been found to have attenuated peak exercise responses in previous research. However, it is unknown if the pattern of age-associated changes in HR or aerobic capacity (VO2peak) is similar to individuals without disabilities.

Purpose: To investigate age-related changes in aerobic capacity in persons with MR, with and without DS, using a retrospective analysis.

Cardiac autonomic function and baroreflex changes following 4 weeks of resistance versus aerobic training in individuals with pre-hypertension.

Aim: Cardiac autonomic modulation and baroreflex sensitivity (BRS) are altered in individuals with hypertension. Aerobic exercise (AE) training has been shown to improve both measures, yet little is known about the effects of resistance exercise (RE). The purpose of this study was to examine the heart rate variability (HRV) and BRS following 4 weeks of resistance or aerobic training in a population with borderline high blood pressure (BP).

Relation of cardiorespiratory fitness to inflammatory markers, fibrinolytic factors, and lipoprotein(a) in patients with type 2 diabetes mellitus.

Increased inflammation, fibrinolytic factors, and lipoprotein(a) (LP[a]) were associated with increased cardiovascular events in patients with type 2 diabetes, whereas higher levels of cardiorespiratory fitness (CRF) were associated with a lower incidence of cardiovascular mortality. Whether CRF is associated with inflammatory markers, fibrinolytic factors, and LP(a) in patients with type 2 diabetes was investigated. A total of 425 men with type 2 diabetes (mean age 55 +/- 8 years) who participated in a medical screening program were studied.

Arterial structure and function in physically active persons with spinal cord injury.

Objective: We tested the hypothesis that physically active people with spinal cord injury do not have increased subclinical atherosclerosis compared with an age-matched able-bodied group.

Methods: Subjects comprised 28 wheelchair athletes with spinal cord injury (mean age 22 (standard deviation (SD) 3) years) and 24 recreationally active aged-matched able-bodied control participants (mean age 23 (SD 3) years). Intima media thickness, arterial compliance and beta stiffness of the common carotid artery were measured using B-mode ultrasound.

Arterial function in youth: window into cardiovascular risk.

Noninvasive measures of arterial function, such as intima-media thickness (IMT), endothelial function, and arterial stiffness are associated with and are prognostic of cardiovascular events in adults. Postmortem evidence, however, has established that the atherosclerotic process starts in childhood. Furthermore, cardiovascular morbidities in childhood disrupt arterial health and may lead to adverse outcomes in adulthood.

Fractal scaling properties of heart rate dynamics following resistance exercise training.

With aging and disease, there is a breakdown of the natural fractal-like organization of heart rate (HR). Fractal-like correlation properties of HR can be assessed with detrended fluctuation analysis (DFA). A short-time scaling exponent (alpha(s)) value of 1 is associated with healthy HR dynamics, whereas values that deviate away from 1, in either direction, indicate fractal collapse.

Effect of 4 weeks of aerobic or resistance exercise training on arterial stiffness, blood flow and blood pressure in pre- and stage-1 hypertensives.

The benefits of aerobic exercise (AE) training on blood pressure (BP) and arterial stiffness are well established, but the effects of resistance training are less well delineated. The purpose of this study was to determine the impact of resistance vs aerobic training on haemodynamics and arterial stiffness. Thirty pre- or stage-1 essential hypertensives (20 men and 10 women), not on any medications, were recruited (age: 48.