OBJECTIVE: Vehicular speeds have been identified to be at the core of road accident severity and frequency globally. Whereas speed control is a fundamental priority and the cornerstone of road safety in the developed world, the subject is at rudimentary stages in most developing countries thus making research into vehicle ...

Load carriage is a key element in dismounted military operations. Load carriage requirements in the field regularly exceed 50% of lean body mass (LBM) and have only rarely been studied. Therefore, our purpose was to determine the metabolic and motivational effects of heavy loads (30-70% LBM) during constant-rate "road" marching ...

We assessed heart rate (HR) recovery following peak exercise before and after a 12-week cardiac rehabilitation program in 14 children, 12.1+/-1.8 years of age, with repaired complex congenital heart disease (CHD; 11 with Fontan surgery) and impaired exercise performance. Exercise testing using bicycle ergometry was performed at baseline, after completion ...

BACKGROUND: Peripheral arterial disease (PAD) is a risk factor for cardiovascular events. This study assessed the prognostic significance of repeated ankle-brachial index (ABI) measurements at rest and after exercise in patients with PAD receiving conservative treatment. METHODS: In a cohort study of 606 patients (mean age 62+/-12 years, 68% male), ...

Recent evidence supports the use of certain soccer drills for combined technical and physical training. Therefore, it is important to be able to accurately monitor training intensity during soccer drills intended for physical development to allow the optimization of training parameters. Twenty-eight professional soccer players were assessed for heart rate ...

The aim of the present investigation was to compare the accuracy of the heart-rate (HR) deflection point (HRDP) and the second HR variability threshold (HRVTh2) to predict anaerobic threshold in boys. HRDP was determined from slope trends of successive linear regressions. HRVTh2 was determined from the high frequency's peak and ...

The aim of this study was to investigate the physiological load of free practices (F), qualifying sessions (Q), and official races (R) of motorcycling competitions. Twenty-six female riders (age: 30.8 +/- 6.1 yrs) participated in this study. Anthropometric and strength evaluations were performed. Subject's heart rate (HR) was continuously recorded ...

BACKGROUND/OBJECTIVE: The Actiheart (Mini Mitter, Sunriver, OR, USA) uses heart rate (HR) and activity data to predict activity energy expenditure (AEE). Currently, the Actiheart has only been tested during laboratory conditions. Therefore, the objective of this study was to validate the Actiheart prediction method against indirect calorimetry during a wide ...

Several methods are used to estimate anaerobic threshold (AT) during exercise. The aim of the present study was to compare AT obtained by a graphic visual method for the estimate of ventilatory and metabolic variables (gold standard), to a bi-segmental linear regression mathematical model of Hinkley's algorithm applied to heart ...

We examined potential mechanisms (autonomic function, hypotension, and cerebral hypoperfusion) responsible for orthostatic intolerance following prolonged exercise. Autonomic function and cerebral hemodynamics were monitored in seven athletes pre-, post- (<4 h), and 48 h following a mountain marathon [42.2 km; cumulative gain approximately 1,000 m; approximately 15 degrees C; completion ...

The purpose of the present study was to evaluate the reliability of the oxygen consumption/heart rate (VO(2)/HR) relationship used to estimate energy expenditure during a workday. Before and after a 6-10 h work shift, the VO(2)/HR relationship was measured in 57 workers (28 female, 29 male) in our laboratory. VO(2) ...

Heart rate (HR) and ratings of perceived exertion (RPE) are common exercise intensity regulatory strategies, however, some individuals are unable to use these strategies effectively. Alternative or conjunctive strategies may aid in the transition to self-guided programs. The purpose of the present study was to examine the value of a ...

The purpose of this study was to examine the effects of muscular power engagement, anaerobic participation, aerobic power level, and energy expenditure on postexercise parasympathetic reactivation. We compared the response of heart rate (HR) after repeated sprinting with that of exercise sessions of comparable net energy expenditure and anaerobic energy ...

AIM: Ratings of perceived exertion (RPE) have been shown similar across subjects of varying fitness when estimations are made at relative physiological criteria. Because few studies have investigated the influence of fitness during longer duration bouts, the current investigation compared overall exertion (RPE-O), leg exertion (RPE-L) and breathing/chest exertion (RPE-C) ...

We sought to determine if resetting of the carotid-vasomotor baroreflex function curve during exercise is modulated by changes in central blood volume (CBV). CBV was increased during exercise by altering: (1) subject posture (supine versus upright) and (2) pedal frequency (80 versus 60 revolutions min(-1) (r.p.m.)); while oxygen uptake ( ...

RATIONALE: The effects of chronic moderate alcohol consumption on cardiac function are not understood. Acute stress may affect cardiac function by shifting autonomic cardiac regulation in favor of the sympathetic nervous system. Although alcohol consumption often increases at times of stress, the interactive effects of stress and chronic moderate alcohol ...

Hypoperfusion of active skeletal muscle elicits a reflex pressor response termed the muscle metaboreflex. Dynamic exercise attenuates spontaneous baroreflex sensitivity (SBRS) in the control of heart rate (HR) during rapid, spontaneous changes in blood pressure (BP). Our objective was to determine whether muscle metaboreflex activation (MRA) further diminishes SBRS. Conscious ...

The purpose of this study was to determine the reliability and validity of regulating exercise intensity by ratings of perceived exertion in step dance sessions. Ten male college-aged students voluntarily participated in 2 step dance sessions for 45 minutes at 70-80% of their heart rate (HR) reserves with a 1-week ...

In order to determine whether there is any difference between voltage-gated calcium-channel antibody (VGCC-Ab)-positive and -negative groups in Lambert-Eaton myasthenic syndrome (LEMS), we compared the clinical and electrophysiological features between 13 patients with VGCC-Ab and 6 VGCC-Ab-negative patients. No obvious difference was observed in the various clinical features or findings ...

This study examined the strategy utilized by patients with cardiovascular disease to regulate exercise intensity using the Rating of Perceived Exertion (RPE) and tested if a step-up procedure would reduce overshoot of target heart rate (HR). Also the study investigated if Prescription Congruence and Intensity Discrimination, components of the Intensity ...

The cardiovascular consequences of hypoestrogenism in premenopausal women are unclear. Accordingly, the influence of menstrual status and endogenous estrogen (E(2)) exposure on blood pressure (BP), heart rate (HR), and calf blood flow in young (18-35 yr) regularly exercising premenopausal women with exercise-associated menstrual aberrations was investigated. Across consecutive menstrual cycles, ...

A major part of the ME consumed by ruminants (MEI) is dissipated as heat. This fraction, called heat production or energy expenditure (EE), is assayed largely by measuring O2 consumption (VO2). Conventional measurement of EE in controlled conditions in chambers does not reflect the complexity of natural, environmental, and social ...

Spontaneous baroreflex function and vascular changes were assessed in young adults during dynamical mild exercise. Windkessel time constant was assessed by two different methods: two-element windkessel model, and by an autoregressive (AR) model, while the baroreflex sensitivity (BRS, ms/mmHg) was assessed by the sequence method. Results showed a change in ...

PURPOSE: Circadian variation of the heart rate (HR) at the myocardial ischemic threshold was compared with that of the HR at the sympathetic tone threshold in 16 cases of effort angina pectoris. METHODS: The high (0.15-0.40 Hz, Hf) and low (0.03-0.15 Hz, Lf) frequency spectral components were extracted every twenty ...

The autonomic nervous system plays a critical role in regulating the cardiovascular responses to mental and physical stress. Recent neuroimaging studies have demonstrated that sympathetic outflow to the heart is modulated by the activity of the anterior cingulate cortex (ACC). However, the cortical modulation of cardiovagal activity is still unclear ...

BACKGROUND: Failure to reach 80% of maximal predicted heart rate (HR) during exercise may render a myocardial perfusion single photon emission computed tomography (SPECT) study non-diagnostic for ischemia detection. We sought to investigate the injection of atropine in patients who fail to achieve 80% of age-predicted HR during exercise performed ...

Social experiences, both positive and negative, may influence cardiovascular regulation. Prairie voles (Microtus ochrogaster) are socially monogamous rodents that form social bonds similar to those seen in primates, and this species may provide a useful model for investigating neural and social regulation of cardiac function. Cardiac regulation has not been ...

OBJECTIVE: This study examined the effects of in-task, moderate-intensity aerobic exercise on neuroelectric and behavioral indices of interference control, one component of executive control. METHODS: Forty-one participants completed a V O(2) max test to determine maximal heart rate (HR). On a separate day, event-related brain potentials and task performance were ...

Ventromedial prefrontal cortex (VMPFC) lesions can alter emotional and autonomic responses. In animals, VMPFC activation results in cardiovascular sympathetic inhibition. In humans, VMPFC modulates emotional processing and autonomic response to arousal (e.g. accompanying decision-making). The specific role of the left or right VMPFC in mediating somatic responses to non-arousing, daily-life ...

Different types of adaptation of the cardiovascular system to the gravitational forces (hypokinetic and hyperkinetic) have been described in the healthy and the sick subjects under resting conditions. The aim of the present study was to elucidate whether haemodynamic responses to the dynamic exercise performed under various gravitational conditions are ...

RATIONALE: Heart rate (HR) and oxygen consumption (VO(2)) are indicators of the intensity of exercise. Handrail support has been shown, during maximal treadmill testing, to blunt HR and VO(2) responses at a particular speed and grade, resulting in an increased treadmill time and overprediction in aerobic capacity. OBJECTIVES: This study ...

OBJECTIVE: This study aims to investigate the effect of transcutaneous electrical nerve stimulation, applied at bilateral acupuncture points PC6 (Acu-TENS), on recovery heart rate (HR) in healthy subjects after treadmill running exercise. DESIGN: A single blinded, randomized controlled trial. SETTING: Laboratory with healthy male subjects (n=28). INTERVENTIONS: Each subject participated ...

To compare upper airway mechanics, arterial blood gases, and tracheal contamination in horses with induced left laryngeal hemiplegia (recurrent laryngeal neuropathy [RLN]) treated by laryngoplasty/vocal cordectomy (LPVC) or modified partial arytenoidectomy (MPA). Repeated measures under the following conditions: Control, RLN, LPVC, and MPA. Six horses. Two trials were conducted under ...

Both a large heart rate (HR) increase at exercise onset and a slow heart rate (HR) recovery following the termination of exercise have been linked to an increased risk for ventricular fibrillation (VF) in patients with coronary artery disease. Endurance exercise training can alter cardiac autonomic regulation. Therefore, it is ...

The cardiovascular adaptation at the onset of voluntary static exercise is controlled by the autonomic nervous system. Two neural mechanisms are responsible for the cardiovascular adaptation: one is central command descending from higher brain centers, and the other is a muscle mechanosensitive reflex from activation of mechanoreceptors in the contracting ...

BACKGROUND: Heart rate recovery (HRR) during exercise testing is an independent predictor of prognosis. The relative predictive power of computational analysis of HRR as a function of resting and maximum heart rate (HR) compared with direct measurement of the drop in HR has not been determined. HYPOTHESIS: We aimed to ...

AIM: The purpose of this study was to investigate the relationship between the influence of music on RPE during sub-maximal exercise and on the autonomic nervous system before and after sub-maximal exercise. METHODS: Heart rate (HR), HR variability (HRV) and rates of physical fatigue (RPE) during exercise at 60% and ...

BACKGROUND: The aim of this study was to clarify the influence of sympathetic and parasympathetic nerve (SN and PN) dysfunction on the heart rate (HR) response to exercise and the exercise capacity of patients with acute myocardial infarction (AMI) and diabetes mellitus (DM). METHODS AND RESULTS: Fifty-two male patients who ...

REASONS FOR PERFORMING STUDY: Field based studies of changes in fitness are difficult to conduct in galloping Thoroughbreds. Measurements of heart rate (HR) and real time velocity with a global positioning system (GPS) could provide a method for routine field studies of fitness. OBJECTIVE: To investigate measurements of fitness in ...

The purpose of this investigation was to relate the heart rate and lactate response during simulated cycling time trials to incremental laboratory tests. Subjects (N = 10) were tested for .V(O2)max (56.1 +/- 2.4 ml.kg(-1).min(-1) ) and lactate threshold during incremental tests to exhaustion. Power output and heart rate (HR) ...

All 75-year-olds born in 1914 and living in the city of Jyväskylä, central Finland (n=388) were invited to study the predictive value of exercise test for mortality. Subjects who entered the laboratory (n=295) were to have a standard pre-test evaluation and perform a cycle ergometer exercise test. Subjects with complete ...

PURPOSE: Heart failure (HF) is associated with blunted HR recovery after exercise. The determinants of altered HR recovery in HF are unknown. The aim of this study was to investigate clinical correlates of HR recovery in HF patients. METHODS: Echocardiography, pulmonary function tests, exercise testing, and neurohormonal measurements were performed ...

The relative acute toxicity of spent lubricant oil and detergent was evaluated against hermit crab, Clibanarius africanus (Aurivillus) and periwinkle, Tympanotonus fuscatus (L) from the Lagos lagoon in laboratory bioassays. Based on the derived toxicity indices, the detergent (96 hr LC50 = 5.77ml/l) was found to be 1.73 times more ...

BACKGROUND: Measurement of pulse wave velocity (PWV) provides a reliable index of vascular stiffness. Despite its widespread application, the physiological interrelationships between PWV, blood pressure (BP) and in particular, heart rate (HR), have yet to be fully elucidated. Furthermore, little is known about altered arterial compliance during acute exercise. AIM: ...

INTRODUCTION: Exercise intensity is often regulated in hot conditions by maintaining a constant target heart rate (HR) to counteract increased physiological strain and thereby avoid premature fatigue. It is unknown, however, whether the HR-percent maximal oxygen uptake (%VO2max) relationship is maintained during prolonged exercise in the heat when the rise ...

Fear conditioning models of posttraumatic stress disorder (PTSD) propose that noradrenergic activation at the time of trauma leads to over-consolidation of trauma memories and contributes to PTSD. This model suggests that resting heart rate (HR) in the acute phase after trauma may reflect the strength of the noradrenergic response and ...

The goal of this study was to evaluate the physiological responses during incremental field tests (FT) in nordic walking (NW), walking (W) and jogging (J). Fifteen healthy middle-aged women participated in three FT. Heart rate (HR) and oxygen uptake (V(O)(2)) were monitored continuously by portable analyzers. Capillary blood lactate (La) ...

We tested whether the G894T and T-786C NOS3 polymorphisms were associated with exercise cardiovascular (CV) hemodynamics in sedentary, physically active, and endurance-trained postmenopausal women. CV hemodynamic parameters including heart rate (HR), systolic (SBP) and diastolic (DBP) blood pressures and cardiac output (Q), as determined by acetylene rebreathing, stroke volume (SV), ...

PURPOSE: Exercise has been recommended as a way to maintain quality of life in individuals with Parkinson disease (PD). Experiments examining the cardiovascular response to exercise, however, have yielded controversial results. This study was designed to determine if there is any difference in vital signs and Rate of Perceived Exertion ...

We aimed to determine the frequency of the VO2max plateau phenomenon in top-level male professional road cyclists (n = 38; VO2max [mean +/- SD]: 73.5 +/- 5.5 ml.kg(-1).min(-1)) and in healthy, sedentary male controls (n = 37; VO2max: 42.7 +/- 5.6 ml.kg(-1).min(-1)). All subjects performed a continuous incremental cycle-ergometer test ...