INTRODUCTION/PURPOSE: This study investigated the effects of three different doses of caffeine on physiological responses to exercise in young children. METHODS: Forty healthy children (20 boys and 20 girls) volunteered for a random, double-blind, counterbalanced study where they received either placebo (PL), 1 mg.kg(-1) (CAF-1), 3 mg.kg(-1) (CAF-3), or 5 ...

OBJECTIVE: Cardiovascular drift (CVdrift) is characterised by a continuous, gradual increase in heart rate (HR) after approximately 10 min of moderate-intensity aerobic exercise, despite maintenance of a constant work rate. This has important implications for trials that employ HR to monitor exercise intensity, as reducing work rate in order to ...

PURPOSE: Heart rate (HR) recovery during the first minute after cessation of exercise is predominantly modulated by reactivation of vagal tone. Attenuated 1-min HR recovery is a cardiovascular risk factor in adults. The purpose of this study was to determine predictors of 1-min HR recovery after a maximum-effort exercise test ...

To determine whether a 4-a-side handball (HB) game is an appropriate aerobic stimulus to reach and potentially enhance maximal oxygen uptake (V O(2)max), and whether heart rate (HR) is a valid index of V O(2) during a handball game. Nine skilled players (21.0+/-2.9 yr) underwent a graded maximal aerobic test ...

Heart rate (HR) profile during exercise predicts all-cause mortality. However, less is known about its relation to sudden (vs nonsudden) death in asymptomatic people. The relation of exercise HR parameters (HR at rest, target HR achievement, HR increase, and HR recovery) with sudden death, coronary heart disease (CHD) death, myocardial ...

The origin of heart rate variability (HRV) is largely in parasympathetic activity. The direct influence of sympathetic activity and other control mechanisms, especially at an increased HR, is not well understood. The objectives of the study were to investigate the influence of increasing HR on the properties of heartbeat interval ...

To investigate the regional hemodynamic responses of abdominal arteries at the onset of exercise and to focus on their transient responses, eight female subjects (21-30 yr) performed ergometer cycling exercise at 40 W for 4 min in a semi-supine position. Mean blood velocities (MBVs) in the right renal (RA), superior ...

The aim of this study was to determine the magnitude and pattern of intensity, and physiological strain, of competitive exercise performed across several days, as in adventure racing. Data were obtained from three teams of four athletes (7 males, 5 females; mean age 36 years, s = 11; cycling .VO(2 ...

OBJECTIVE: A meta-analysis was conducted on the effect of overload training on resting HR, submaximal and maximal exercise HR (HR), and heart rate variability (HRV), to determine whether these measures can be used as valid markers of over-reaching. METHODS: Six databases were searched using relevant terms and strategies. Criteria for ...

The rating of perceived exertion (RPE) could be a practical measure of global exercise intensity in team sports. The purpose of this study was to examine the relationship between heart rate (%HR(peak)) and blood lactate ([BLa(-)]) measures of exercise intensity with each player's RPE during soccer-specific aerobic exercises. Mean individual ...

BACKGROUND: The diving response includes cardiovascular adjustments known to decrease oxygen uptake and thus prolong apnea duration. As this diving response is in part characterized by a pronounced decrease in heart rate (HR), it is thought to be vagally mediated. METHODS: In five professional breath-hold divers (BHDs) and five less-trained ...

OBJECTIVES: To compare the intensity of three exercise training regimens. BACKGROUND: During a cardiac rehabilitation program coronary artery disease (CAD) patients should be trained at an intensity as close as possible to the ventilatory threshold (VT) level. The precise way to obtain this intensity of training during the sessions, however, ...

A field study was conducted to highlight the occupational risk factors related to building construction activities in India among female workers. These workers were engaged in eight different types of activities and related work parameters were studied in detail. From field environmental parameters, the calculated WBGT was obtained as 30.26+/-1.52 ...

We have previously shown that spontaneous baroreflex-induced changes in heart rate (HR) do not always translate into changes in cardiac output (CO) at rest. We have also shown that heart failure (HF) decreases this linkage between changes in HR and CO. Whether dynamic exercise and muscle metaboreflex activation (via imposed ...

Rate of perceived exertion (RPE) is a clinically convenient indicator for monitoring exercise intensity in cardiopulmonary rehabilitation. It might not be sensitive enough for clinicians to determine the patients’ physiological status because its association with the cardiovascular system and local muscle factors is unknown. This study used the electromyographic sensor ...

Tai Chi Chuan (TC) is a Chinese conditioning exercise and is well-known for its graceful movement. The exercise intensity of TC depends on its training style, posture and duration. Variation in training approaches result in substantial differences in exercise intensity. We have measured heart rate (HR) and oxygen uptake (VO2) ...

We compared delayed-onset muscle soreness (DOMS) induced by anaerobic resistance exercises with and without aerobic cardioacceleration before each set, under the rationale that elevated heart rate (HR) may increase blood perfusion in muscles to limit eccentric contraction damage and/or speed muscle recovery. In two identical experiments (20 men, 28 women), ...

The aim of this study was to determine how one group of lambs utilized 2 consecutive rest periods in novel environments with access to food and water that occurred during 22 hr of motor transport. The 18.5 +/- 0.6 kg lambs (n = 15) were transported for 8 hr and ...

To evaluate whether cardiovascular responses to maximal exercise testing and recovery are altered with obstructive sleep apnea (OSA) in overweight young adult men. Three sedentary subject groups were recruited: Overweight with OSA (OSA), overweight without OSA (No-OSA), and normal weight without OSA (Control). Presence of OSA was screened via portable ...

The effect of seizures on instantaneous HR (iHR) in 12 neonates is investigated here. HR can be readily extracted from the ECG and can be employed as an additional signal in seizure detection algorithms. The change in instantaneous HR and its correlation with the change in RMS EEG amplitude were ...

The purpose of the present study was to characterize the physiological demands of postmen during a work day composed of mail sorting (inside work, IW) and cycling distribution (outside work, OW). Two groups of postal workers were constituted according to the geographical profile of their distribution courses: flat profile (FP; ...

ABSTRACT: Very few studies have analysed heart rate (HR) with regard to music playing, and the scarce evidence available is controversial. The purpose of this study was to analyse the HR response of professional musicians during their real-work activity. Sixty-two voluntary professional musicians (20 women, 42 men), whose ages ranged ...

A paucity of empirical research exists into surf lifesaving competition from which coaches and athletes may formulate training and recovery strategies. Seventeen (male=9; female=8) high-performance surf lifesavers (21.2+/-3.9 years) contested multiple rounds of team and individual events at a 2-day surf lifesaving competition. Individual events consisted of the multi-discipline ironman ...

The purpose of this study was to assess the heart rate (HR) and blood pressure (BP) response of sexual activity compared with treadmill exercise in adult men and women. Nineteen men, 55 +/- 8 years, and 13 women, 51 +/- 7 years, underwent a maximal Bruce protocol treadmill stress test ...

We examined whether spontaneous baroreflex modulation of heart rate and other indexes of cardiac vagal tone could be altered by passive stretch of the human calf muscle during graded concurrent activation of the muscle metaboreflex. Ten healthy subjects performed four trials: a control trial, resting for 1.5 min (0% trial); ...

The purpose of this study is to describe the physiological responses occurring during slot gambling in 23 females with problematic and non-problematic gambling backgrounds in two sites: at a casino using their own money and at a casino laboratory without wagering money. Using the National Opinion Research Center Diagnostic Screen ...

BACKGROUND/AIM: Non-tunneled, temporal hemodialysis (HD) catheters are commonly used as short-term vascular access for the HD procedure. One of their late complications is thrombotic occlusion of the catheter ensuing in their malfunction. A heparin lock is conventionally used for maintaining the patency of the catheter. The aim of the study ...

OBJECTIVE: The effect of stimulant medication on exercise responses was studied in 14 boys (10.9 +/- 1.1 years) with attention deficit/hyperactivity disorder (ADHD). METHOD: Exercise, with and without medication, was performed at 25 W, 50 W, and 75 W, followed by a peak exercise test. RESULT: Submaximal heart rate (HR) ...

This study examined the exercise intensity and load of the mountain passes of the major 3-week races according to their difficulty (length and slope) and position within the stage, using competition heart rate (HR). Sixteen world-class cyclists performed a laboratory test to assess maximal power output (W (max)), maximal HR ...

PURPOSE: The 6-minute walk test (6MWT) is used to predict aerobic capacity, evaluate functional performance, and assess the risk of mortality and morbidity of several chronic conditions. The purpose of this study was to determine the validity and reliability of the 6MWT on a treadmill, thus increasing the clinical use ...

PURPOSE: Analgesic balms (AB) are widely used in sports medicine. We previously have examined effects of various counterirritant-based AB on pressor responses evoked by muscular contraction (MC), mediated by group III and IV muscle afferents known to produce exercise and nociceptive responses. Our purpose was to examine trolamine salicylate-based analgesic ...

The purpose of this study was to investigate the postactivation potentiation effect after a heavy resistance stimulus (HRS) on running speed (RS). Fifteen amateur team game players (basketball, volleyball, handball, and soccer players), ages 18-23 years running the 30-m dash and the intermediate phase of 0-10 and 0-30 m sprints, ...

BACKGROUND: Cardiac autonomic innervation modulates heart rate (HR) response during and HR recovery after exercise in normal subjects. Heart transplantation results in surgical interruption of autonomic innervation. We assessed whether HR response during exercise and HR recovery after exercise in pediatric heart transplant recipients are consistent with autonomic denervation of ...

Increases in cadence may augment SV during submaximal cycling (> 65 % VO2max) via effects of increased muscle pump activity on preload. At lower workloads (45 - 65 % VO2max), SV tends to plateau, suggesting that effects of increases in cadence on pump activity have little influence on SV. We ...

We tested the hypotheses that women completing 56 days, 6 degrees head-down bed-rest (HDBR) would have changes in sensitivity of cardiovascular responses to adrenergic receptor stimulation and that frequent aerobic and resistive exercise would prevent these changes. Twenty-four women, eight controls, eight exercisers (lower body negative pressure treadmill and flywheel ...

The ageing process has the potential to impact upon the manner in which an athlete responds to training stimuli. This study investigated if power output (PO) and heart rate (HR) at the modified D-max lactate transition threshold (D-max) was comparable with the mean HR and power that could be sustained ...

PURPOSE: To evaluate the effect, and the duration of the effect, of topically administrated travoprost and unoprostone on optic nerve head (ONH) circulation in Dutch rabbits. METHODS: First, travoprost (0.004% solution) or unoprostone (0.12% solution) was unilaterally instilled once, or once daily (travoprost) or twice daily (unoprostone) for 7 days ...

We tested the validity of an new methodological approach to the calculation of oxygen uptake efficiency slope (OUES) [i.e. the use of exercise end-points based on fractions of heart rate reserve (HR(res))], as an alternative to the traditional time-based calculation. Twenty-nine healthy sedentaries >60 years of age (18 males, 11 ...

This study assessed whether the accuracy of predicting maximal oxygen uptake (VO2max) from sub-maximal heart rate (HR) and ratings of perceived exertion (RPE) values was moderated by gender and habitual activity. In total, 27 men and 18 women completed two GXTs to determine VO2max and three perceptually-regulated GXTs, incremented by ...

Patients with postural tachycardia syndrome (POTS) have excessive tachycardia without hypotension during orthostasis as well as exercise. We tested the hypothesis that excessive tachycardia during exercise in POTS is not related to abnormal baroreflex control of heart rate (HR). Patients (n = 13) and healthy controls (n = 10) performed ...

The purpose of this study was to quantify intermittent training sessions using different types of exercise. Strength, sprint, and endurance sessions were performed until exhaustion. These sessions were quantified by the product of duration and heart rate (HR) (i.e., training impulse (TRIMP) and HR-zone methods), by the product of duration ...

Postural tachycardia syndrome (POTS) is characterized by excessive tachycardia without hypotension during orthostasis. Most POTS patients also report exercise intolerance. To assess cardiovascular regulation during exercise in POTS, patients (n = 13) and healthy controls (n = 10) performed graded cycle exercise at 25, 50, and 75 W in both ...

Many fish species adapt to hypoxia by reducing their metabolic rate and increasing hemoglobin-oxygen (Hb-O(2)) affinity. Pilot studies with young broods of cichlids showed that the young could survive severe hypoxia in contrast with the adults. It was therefore hypothesized that early exposure results in improved oxygen transport. This hypothesis ...

Passive postexercise heart rate (HR) recovery is currently used in the assessment of endurance athletes to determine changes in performance or in the clinical setting as a predictor of all-cause mortality. The purpose of this investigation was to assess the reliability of HR recovery. Thirty healthy subjects performed two maximal ...

In general, cardiac regulation is dominated by the sympathetic and parasympathetic nervous systems in men and women, respectively. Our recent study had revealed sex differences in the forebrain network associated with sympathoexcitatory response to baroreceptor unloading. The present study further examined the sex differences in forebrain modulation of cardiovagal response ...

BACKGROUND: Abnormal exercise-related heart rate (HR) dynamics, that is, blunted exercise HR response, lower peak HR, and delayed HR recovery after exercise, are associated with high morbidity and mortality in adults with acquired and congenital heart disease (CHD). However, the precise mechanisms underlying the abnormal HR dynamics remain unclear. OBJECTIVES: ...

Embryos of the annual killifish Austrofundulus limnaeus can experience oxygen deprivation as part of their normal developmental environment. We exposed embryos to anoxia and monitored heart activity for 48 hr, and subsequent aerobic recovery from anoxia for 40 hr. Embryos were tested at four different developmental stages that differ in ...

We sought to examine the influence of exercise intensity on carotid baroreflex (CBR) control of heart rate (HR) and mean arterial pressure (MAP) at the onset of exercise in humans. To accomplish this, eight subjects performed multiple 1-min bouts of isometric handgrip (HG) exercise at 15, 30, 45 and 60% ...

This study examined cardiovascular responses as a function of time following exercise in which participants were exposed to a laboratory stressor. Ninety (42 women) young (18-35 years old) nonsmoking normotensive participants engaged in 30 min of high and low intensity (75-80% and 50-55% VO(2) max) aerobic exercise and a sedentary ...

OBJECTIVES: Heart rate (HR) accelerates with the electroconvulsive therapy (ECT) seizure and decelerates when it ends. The peak HR during ECT seizure has been reported to reflect clinical impact. We aimed to identify the expected range for ECT peak HR and how it varies with age and sex, as a ...