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Exercise and heart

Derek Nelson, Rachael M Heuer, Georgina K Cox, John D Stieglitz, Ronald Hoenig, Edward M Mager, Daniel D Benetti, Martin Grosell, Dane A Crossley
Exposure to polycyclic aromatic hydrocarbons (PAH) negatively impacts exercise performance in fish species but the physiological modifications that result in this phenotype are poorly understood. Prior studies have shown that embryonic and juvenile mahi-mahi (Coryphaeus hippurus) exposed to PAH exhibit morphological abnormalities, altered cardiac development and reduced swimming performance. It has been suggested that cardiovascular function inhibited by PAH exposure accounts for the compromised exercise performance in fish species...
October 14, 2016: Aquatic Toxicology
Sijie Tan, Cheng Chen, Mingyang Sui, Lunan Xue, Jianxiong Wang
OBJECTIVES: To explore the effects of exercise training on body composition, cardiovascular function, and physical fitness in 5-year-old obese and lean children. METHODS: 42 obese and 62 lean children were randomly allocated into exercise and control groups separately. Body composition, cardiovascular function, and physical fitness were measured at baseline and the end of the intervention. The exercise groups participated in 10 weeks of supervised moderate intensity exercise training (at 50% of heart rate reserve), 50 training sessions in total...
October 21, 2016: Pediatric Exercise Science
Matthijs T W Veltmeijer, Dineke Veeneman, Coen C C W Bongers, Mihai G Netea, Jos W van der Meer, Thijs M H Eijsvogels, Maria T E Hopman
PURPOSE: Exercise increases core body temperature (TC) due to metabolic heat production. However, the exercise-induced release of inflammatory cytokines including interleukin-6 may also contribute to the rise in TC by increasing the hypothalamic temperature setpoint. We aimed to investigate whether the exercise-induced increase in TC is partly caused by an altered hypothalamic temperature setpoint. METHODS: 15 healthy, active male subjects aged 36±14 years were recruited...
September 26, 2016: International Journal of Sports Physiology and Performance
Daniel J Peart, Andy Hensby, Matthew P Shaw
The purpose of this study was to compare markers of hydration during sub-maximal exercise and subsequent time trial performance when consuming water (PW) or coconut water (CW). There was also a secondary aim to assess the palatability of CW during exercise and voluntary intake during intense exercise. 10 males (age 27.9 + 4.9 years, body mass 78.1 + 10.1kg, average max minute power 300.2 + 28.2W) completed 60-min of sub-maximal cycling followed by a 10-km time trial on two occasions. During these trials participants consumed either PW or CW in a randomised manner, drinking a 250 ml of the assigned drink between 10-15 min, 25-30 min and 40-45 min, and then drinking ad libitum from 55-min until the end of the time trial...
October 21, 2016: International Journal of Sport Nutrition and Exercise Metabolism
Walter H Reinhart
The hematocrit (Hct) determines the oxygen carrying capacity of blood, but also increases blood viscosity and thus flow resistance. From this dual role the concept of an optimum Hct for tissue oxygenation has been derived. Viscometric studies using the ratio Hct/blood viscosity at high shear rate showed an optimum Hct of 50-60% for red blood cell (RBC) suspensions in plasma. For the perfusion of an artificial microvascular network with 5-70μm channels the optimum Hct was 60-70% for high driving pressures. With lower shear rates or driving pressures the optimum Hct shifted towards lower values...
October 21, 2016: Clinical Hemorheology and Microcirculation
Nicholas J Hanson, Janet Buckworth
Time perception during exercise may be affected by chosen intensity, and may also affect enjoyment of exercise and subsequent long-term adherence. However, little is known about how individuals perceive the passage of time during exercise, or if factors such as sex are influential. The purpose of this study was to determine if there are sex related differences in perception of time during a bout of exercise in experienced runners. Twenty-two recreational runners (11 men, 11 women) participated in a bout of treadmill running where they were allowed to select their intensity...
2016: International Journal of Exercise Science
Victor M Niemeijer, Ruud F Spee, Thijs Schoots, Pieter F F Wijn, Hareld M Kemps
The extent and speed of transient skeletal muscle deoxygenation during exercise onset in chronic heart failure (CHF) patients is related to impairments of local O2 delivery and utilization. This study examined the physiological background of submaximal exercise performance in 19 moderately impaired CHF patients (Weber class A, B, and C) compared with 19 matched healthy control (HC) subjects by measuring skeletal muscle oxygenation (SmO2) changes during cycling exercise. All subjects performed two subsequent moderate-intensity 6-minute exercise tests (bout 1 and 2) with measurements of pulmonary oxygen uptake kinetics, and SmO2 using near infrared (NIR) spatially resolved spectroscopy (SRS) at the vastus lateralis for determination of absolute oxygenation values, amplitudes, kinetics (mean response time for onset), and deoxygenation overshoot characteristics...
October 7, 2016: American Journal of Physiology. Heart and Circulatory Physiology
Wojciech Kosmala, Aleksandra Rojek, Monika Przewlocka-Kosmala, Leah Wright, Andrzej Mysiak, Thomas H Marwick
BACKGROUND: Impaired functional capacity is a hallmark of patients with heart failure with preserved ejection fraction (HFpEF). Despite the association of HFpEF with reduced myocardial compliance attributed to fibrosis, spironolactone has not been shown to alter outcomes-perhaps reflecting the heterogeneity of underlying pathological mechanisms. OBJECTIVES: The authors sought to identify improvement in exercise capacity with spironolactone in the subset of patients with HFpEF with exercise-induced increase in ratio between early mitral inflow velocity and mitral annular early diastolic velocity (E/e') reflecting elevation of left ventricular (LV) filling pressure...
October 25, 2016: Journal of the American College of Cardiology
Jian Cui, Cheryl A Blaha, Lawrence I Sinoway
The effects of whole-body heat stress on sympathetic and cardiovascular responses to stimulation of muscle metaboreceptors and mechanoreceptors remains unclear. We examined the muscle sympathetic nerve activity (MSNA), blood pressure and heart rate in 14 young healthy subjects during fatiguing isometric handgrip exercise, post exercise circulatory occlusion (PECO), and passive muscle stretch during PECO. The protocol was performed under normothermic and whole-body heat stress (increase internal temperature ~0...
October 7, 2016: Journal of Applied Physiology
Nastasia Marinus, Liene Bervoets, Guy Massa, Kenneth Verboven, An Stevens, Tim Takken, Dominique Hansen
BACKGROUND: Cardiopulmonary exercise testing is advised ahead of exercise intervention in obese adolescents to assess medical safety of exercise and physical fitness. Optimal validity and reliability of test results are required to identify maximal exercise effort. As fat oxidation during exercise is disturbed in obese individuals, it remains an unresolved methodological issue whether the respiratory gas exchange ratio (RER) is a valid marker for maximal effort during exercise testing in this population...
October 20, 2016: Journal of Sports Medicine and Physical Fitness
Rosario Scarfone, Antonio Ammendolia
BACKGROUND: The aim of this study was to investigate the physiological demands and technical-tactical performances of field players in Italian elite beach soccer team. METHODS: Three official matches of the Italian First Division beach soccer tournament were analyzed to evaluate the heart rate (HR) and time-motion analysis considering: standing, walking, jogging, running and sprinting, and technical-tactical aspects. Repeated-measures ANOVAs were used to determine the effects of time on the physiological measures and time motion analysis...
October 20, 2016: Journal of Sports Medicine and Physical Fitness
Nina Lefeber, Eva Swinnen, Eric Kerckhofs
PURPOSE: The integration of sufficient cardiovascular stress into robot-assisted gait (RAG) training could combine the benefits of both RAG and aerobic training. The aim was to summarize literature data on the immediate effects of RAG compared to walking without robot-assistance on metabolic-, cardiorespiratory- and fatigue-related parameters. METHODS: PubMed and Web of Science were searched for eligible articles till February 2016. Means, SDs and significance values were extracted...
October 20, 2016: Disability and Rehabilitation. Assistive Technology
Raoyrin Chanavirut, Pattarapong Makarawate, Ian A Macdonald, Naruemon Leelayuwat
BACKGROUND: Imbalances of the autonomic nervous (ANS), the cardiovascular system, and ionics might contribute to the manifestation of The Brugada Syndrome (BrS). Thus, this study has aimed to investigate the cardio-respiratory fitness and the responses of the ANS both at rest and during a sub-maximal exercise stress test, in BrS patients and in gender-matched and age-matched healthy sedentary controls. METHODS: Eleven BrS patients and 23 healthy controls were recruited in Khon Kaen, Thailand...
October 2016: Journal of Arrhythmia
Naokata Sumitomo
Catecholaminergic polymorphic ventricular tachycardia (CPVT) is induced by emotions or exercise in patients without organic heart disease and may be polymorphic or bidirectional in nature. The prognosis of CPVT is not good, and therefore prevention of sudden death is of utmost importance. Genetic variants of CPVT include RyR2, CASQ2, CALM2, TRD, and possibly KCNJ2 and ANK2 gene mutations. Hypotheses that suggest the causes of CPVT include weakened binding of FKBP12.6 and RyR2, a store overload-induced Ca(2+) release (SOICR), unzipping of intramolecular domain interactions in RyR2, and molecular and functional abnormalities caused by mutations in the CASQ2 gene...
October 2016: Journal of Arrhythmia
Ryota Kobayashi, Yuto Hashimoto, Hiroyuki Hatakeyama, Takanobu Okamoto
Arterial stiffness increases after glucose ingestion. Acute low- and moderate-intensity aerobic exercise decreases arterial stiffness. However, the acute effects of 30 min of cycling at low- and moderate-intensity [25% (LE trial) and 65% (ME trial) peak oxygen uptake, respectively] on arterial stiffness at 30, 60 and 120 min of a postexercise glucose ingestion. Ten healthy young men (age, 22·4 ± 0·5 years) performed LE and ME trials on separate days in a randomized controlled crossover fashion. Carotid-femoral (aortic) pulse wave velocity (PWV), femoral-ankle (leg) PWV, carotid augmentation index (AIx) and carotid blood pressure (BP) (applanation tonometry), brachial and ankle BP (oscillometric device), heart rate (HR) (electrocardiography), blood glucose (UV-hexokinase method) and blood insulin (CLEIA method) levels were measured at before (baseline) and at 30, 60 and 120 min after the 75-g OGTT...
October 18, 2016: Clinical Physiology and Functional Imaging
Pedro M D Agrícola, Daniel G da Silva Machado, Luiz F de Farias Junior, Luiz I do Nascimento Neto, André I Fonteles, Samara K A da Silva, Cheng H N Chao, Eduardo B Fontes, Hassan M Elsangedy, Alexandre H Okano
Pleasure plays a key role in exercise behavior. However, the influence of cycling cadence needs to be elucidated. Here, we verified the effects of cycling cadence on affect, perceived exertion (ratings of perceived exertion), and physiological responses. In three sessions, 15 men performed a maximal cycling incremental test followed by two 30-min constant workload (50% of peak power) bouts at 60 and 100 r/min. The pleasure was higher when participants cycled at 60 r/min, whereas ratings of perceived exertion, heart rate, and oxygen uptake were lower (p < ...
October 17, 2016: Perceptual and Motor Skills
Attila Oláh, Dalma Kellermayer, Csaba Mátyás, Balázs Tamás Németh, Árpád Lux, Lilla Szabó, Marianna Török, Mihály Ruppert, Anna Meltzer, Alex Ali Sayour, Kálmán Benke, István Hartyánszky, Béla Merkely, Tamás Radovits
PURPOSE: Long-term exercise training is associated with characteristic cardiac adaptation, termed athlete's heart. Our research group previously characterized in vivo left ventricular (LV) function of exercise-induced cardiac hypertrophy in detail in a rat model, however the effect of detraining on LV function is still unclear. We aimed at evaluating the reversibility of functional alterations of athlete's heart after detraining. METHODS: Rats (n=16) were divided into detrained exercised (DEx) and detrained control (DCo) groups...
October 14, 2016: Medicine and Science in Sports and Exercise
Shannon Jordan, Justin Karcher, Rebecca Rogers, Kathleen Kennedy, Anne Lawrence, Jenny Adams
PURPOSE: Updated cardiac rehabilitation (CR) and return-to-work guidelines from the American College of Sports Medicine (ACSM) now include specificity of training for industrial athletes (exercise training that involves the muscle groups, movements, and energy systems that these patients use during occupational tasks). However, many CR facilities do not apply this principle, relying instead on the traditional protocol that consists primarily of aerobic exercise. This study was conducted to measure the metabolic cost of typical farming tasks and to compare 2 methods of calculating training intensities...
October 14, 2016: Journal of Cardiopulmonary Rehabilitation and Prevention
Agathe Gerwina Elena Pollmann, Marianne Frederiksen, Eva Prescott
PURPOSE: Evidence of the effect of cardiac rehabilitation (CR) after heart valve surgery is scarce, but nevertheless CR is recommended for this group of patients. Therefore, this study assessed the effect of CR on exercise capacity, cardiovascular risk factors, and long-term mortality and morbidity, as well as predictors for enrolment in or failing to complete CR. METHODS: A review of medical records identified 250 patients who underwent heart valve surgery between January 2009 and August 2013...
October 14, 2016: Journal of Cardiopulmonary Rehabilitation and Prevention
Hui Li, Jingbo Li, Xiaohong Zhou, Jianrong Zhao, Fengru Zhang, Liqun Wu, Hong Shen, Qing Wan, Jing Huang, Shungang Yang, Ping Wang
Heart failure patients have a high incidence of chronotropic incompetence (CI) that receives less clinical attention. This study assessed a method using wearable devices to identify CI in heart failure patients. Twenty-six heart failure patients (LVEF: 43.9  ±  5.7% with LVEF  ⩾40% in 19 patients; age: 52.8  ±  12.4 years, female patients  =  6) were enrolled. Each patient underwent symptom-limited treadmill maximal exercise testing during which the simultaneous recording of ECG Holter and physical activity using Actigraph was conducted...
October 18, 2016: Physiological Measurement
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