Exercise provides one of the most severe, yet physiological, stresses to the intact cardiovascular system and is a major determinant of the utilization of metabolic substrates. The adaptations to exercise are the result of a coordinated response of multiple organ systems, including cardiovascular, pulmonary, endocrine-metabolic, immunologic, and skeletal muscle. With ...

The compliance of the large elastic arteries in the cardiothoracic circulation declines with age, causing a number of adverse effects on cardiovascular function and disease risk. Recent findings indicate that regular aerobic exercise may favorably modulate age-associated decreases in central arterial compliance and the related adverse physiological and pathophysiological consequences.

The cardiopulmonary adaptations made to dynamic and static exercise show the amazing ability of the human body to alter physiological processes in order to meet metabolic demands. A remarkable partnership that allows individuals to maximize their abilities and obtain goals exists between the cardiovascular and pulmonary systems. The adaptations of ...

In the present paper we have examined the applicability of dimensionless and invariant numbers (DN & IN) to the analysis of the cardiovascular system of mammals, whose functions were measured at standard metabolic conditions. The calculated IN did not change when we compared these figures with those obtained in dogs ...

The exercise pressor reflex is believed to play a role in causing the cardiovascular and ventilatory responses to exercise. This review will discuss the evidence that the reflex is active in both humans and animals. In addition, this review will discuss the nature of the mechanical and metabolic stimuli that ...

This review describes what is known about effects of marijuana and cannabinoids in relation to human physiological and disease outcomes. The acute physiological effects of marijuana include a substantial dose-dependent increase in heart rate, generally associated with a mild increase in blood pressure. Orthostatic hypotension may occur acutely as a ...

An original mathematical model of the cardiovascular response to dynamic exercise is presented. It includes the pulsating heart, the pulmonary and systemic circulation, a separate description of the vascular bed in active tissues, the local metabolic vasodilation in these tissues and the mechanical effects of muscular contractions on venous return. ...

Most cardiovascular activities show a circadian rhythm, as do electrophysiological phenomenon. Under the influence of both external stimuli and endogenous homoeostatic mechanisms, cardiac electrophysiological properties change diurnally and enable the cardiovascular system adapt to rest-exercise cycles. According to recent reports, almost all non-invasive electrophysiological phenomena, such as electrocardiographic indices, cardiac ...

Fine-tuning of the response to exercise that lasts longer than a few seconds is reliant on the regulation of several key variables governing the cardiopulmonary, vascular, and metabolic response to exercise. This type of integrative response requires communication between organ systems that relies on the secretion of endocrine and paracrine ...

The cardiopulmonary exercise test is a valuable method for quantifying global cardiovascular function. It is quantitative, cheap, safe and highly reproducible. Unfortunately, it is highly under-utilized in favor of less quantitative, more expensive and perhaps less safe and reproducible methods. But even if performed, the peak Vo2 is often the ...

Static exercise is well known to increase heart rate, arterial blood pressure, and ventilation. These increases appear to be less in women than in men, a difference that has been attributed to an effect of estrogen on neuronal function. In decerebrate male cats, we examined the effect of estrogen (17beta-estradiol; ...

Little is known about the contribution of over-the-counter (OTC) aspirin to cardiovascular prophylaxis. To investigate this, a two-phase cross-sectional study was carried out in nine general practices in North Staffordshire. In the first phase, all patients with cardiovascular disease (CVD) were identified from computer searches using morbidity registers and drug ...

A mathematical model of cardiovascular response to dynamic exercise is presented, The model includes the pulsating heart, the systemic and pulmonary, circulation, a functional description of muscle exercise hyperemia, the mechanical effects of muscle contractions on hemodynamics, and various neural regulatory, mechanisms working on systemic resistance, venous unstressed volume, heart ...

Research into the physiology of exercise and kinanthropometry is intended to improve our understanding of how the body responds and adapts to exercise. If such studies are to be meaningful, they have to be well designed and analysed. Advances in personal computing have made available statistical analyses that were previously ...

The effects of passive and active orthostatic loads on the amplitude and temporal parameters of pulse waves were studied using an original computer assisted method of differential sphygmomanometry. Changes in the cardiac rhythm reflecting impairment of the autonomic regulation of the circulatory system and preceding neurogenic cardiovascular syncope were revealed ...

In conclusion, much has been learned about the effects of exercise in reducing events in those with CHD. Some data are confusing, however, and some gaping holes exist in our understanding. Hopefully, new data forthcoming in the next 5 to 10 years will clear up this picture significantly. Meanwhile, cardiovascular ...

This brief review addresses current hypotheses concerning the reflex control of circulation during exercise in humans. In particular, the specific objective of this review is to describe how time and frequency domain analysis of blood pressure and heart rate variability signals permitted to gain new insights onto reflex mechanisms of ...

There is heightened concern that older adults and individuals with occult or known heart disease are exercising at fitness facilities that do not provide adequate cardiovascular screening and emergency procedures, as outlined in contemporary recommendations. To evaluate adherence to these standards, we surveyed 122 randomly chosen fitness clubs in Ohio ...

In decerebrate unanesthetized cats, we determined whether either "central command," the exercise pressor reflex, or the muscle mechanoreceptor reflex reset the carotid baroreflex. Both carotid sinuses were vascularly isolated, and the carotid baroreceptors were stimulated with pulsatile pressure. Carotid baroreflex function curves were determined for aortic pressure, heart rate, and ...

Despite significant advances in related technologies, the exercise test remains a useful clinical tool. It can define the limits of performance in an athlete or the functional capabilities of the patient with heart disease. Although virtually all of the body's physiologic and metabolic systems interact in a coordinated fashion to ...

The objective of this review was to give an overview on the current knowledge on the neural mechanisms of cardiovascular regulation during exercise. Evidence derived mainly from human studies which supports the contribution of the different control mechanisms, namely the central command, the reflex drive from active muscles and the ...

The soldierfish (Gymnapistes marmoratus), which is related to the stonefish (Synanceia spp.), inhabits the western, southern and lower eastern coastlines of Australia. We have previously found that G. marmoratus venom possesses pharmacological activity similar to Synanceia trachynis venom (Hopkins, B.J., Hodgson, W.C., 1998. Cardiovascular studies on venom from the soldierfish ...

A 7-year-old male English Coonhound with suspected myxedema coma complicated by severe hypothermia and metabolic abnormalities was treated with a combination of active external and core rewarming techniques, i.v. and oral administration of levothyroxine, supplemental oxygen, and administration of fluids (0.9% NaCl solution). Myxedema coma develops as a consequence of ...

We studied the corneal reflex (CR) with air-puff and direct touch by using a standardized method in patients with thalamic hemorrhage (TH) (n: 15) and in normal control subjects (n: 21). The conventional blink reflex (BR) was also studied. In the TH group: 1--When the cornea on the clinically nonaffected ...

The physiopathogenesis of the cardiovascular deconditioning syndrome observed after actual and simulated microgravity is still under debate, despite numerous studies conducted on the role of blood volume, hormones involved in its regulation, sympathetic nervous system, baroreflexes and venous compliance. Orthostatic intolerance, a reduced exercise capacity and an increased heart rate ...

This article is intended for instructors who teach cardiovascular physiology. In our physiology course exercise physiology is used as a tool to review and integrate cardiovascular and respiratory physiology. It is assumed that the students already have mastered the fundamentals of cardiovascular and respiratory physiology. Because this paper is part ...

Electrocardiographic, biochemical, and physical data obtained from 237 shift and 115 day workers without any obvious disorders were assessed to clarify the impact of shift work on cardiovascular functions. The heart-rate corrected QT interval (QTc) was significantly longer in the shift workers than in the day workers. However, blood pressure, ...

Adaptation, habitution and compensation are the mechanisms involved in rehabilitation of vertigo patients. In Vestibular Rehabilitation Therapy (VRT), patients are advised to perform a series of maneuvers involving head, eye and body movements which stimulate the in-built adaptive mechanisms. Cawthorne and Cooksey were the first to describe adaptation exercises, which ...

Much progress has been made in recent years into understanding molecular mechanisms by which transcription is regulated following changes in physiological stimuli. This review has tried to focus on what is known about four specific physiological challenges--mechanical load, intracellular calcium, hypoxia, and redox state. Because of our biased interest in ...

Robert Battey (1828-1895) introduced bilateral oophorectomy for the treatment of non-ovarian conditions in 1872, coining the term "normal ovariotomy" for the operation. Normal ovariotomy - a contradictio in terminis - was practised widely for several decades. Alfred Hegar (1830-1914), among many other gynaecologists, extended the indications of Battey's operation to ...

Although the adaptability of the neuromuscular junction (NMJ) has been demonstrated using the models of denervation/reinnervation, electrical stimulation, development, aging, and pathological states, relatively little is known about the effects of increased chronic voluntary use on the morphology and physiological function of the NMJ. A review of findings relating to ...

Recent study showed that dehydration induced by prolonged exercise significantly impaired orthostatic tolerance with tachycardia and hypotension, and subsequent rehydration restored it. As physiological changes during exposure to actual or simulated microgravity can be viewed as dehydration process, we hypothesized that rehydration after prolonged bedrest may be a promising candidate ...

Exercise places large demands on the equine cardiovascular system which are further complicated by environmental factors. In many respects, performance is limited by fluid and electrolyte stores and the ability to maintain cardiovascular and thermoregulatory stability in the face of severe sweat losses. Studies in the exercising horse have been ...

The ventilatory and cardiovascular responses, and the rating of perceived exertion (RPE) to three types of unsupported low-intensity upper limb exercise (static, dynamic - unilateral and bilateral) were investigated in 22 normal subjects. A significant increase in tidal volume, respiratory rate, minute ventilation, oxygen consumption, carbon dioxide production and pulse ...

Precise regulatory signals are required in order to adjust the cardiovascular and respiratory systems to meet the demands of exercise. Two neural mechanisms, central command and a reflex originating in contracting muscles, are known to play a large role in exercise-associated adjustments in cardiovascular and respiratory activity. The extent to ...

The main objective of this article is to focus on the loss of cardiovascular adaptations after cessation of exercise. A brief description of the nature of adaptive changes to chronic exercise is given to provide a background and understanding of physiologic mechanisms underlying cardiovascular adaptations to exercise training and their ...

Manipulations of the murine genome that alter cardiovascular function have created the need for methods to study cardiovascular physiology in genetically altered animals in vivo. We adapted chronic physiological measurement techniques to the nonanesthetized, nonrestrained murine model, established strain-specific cardiovascular and metabolic norms, and evaluated responses to anesthesia, exercise, and ...

From the work of Potts et al. Papelier et al. and Shi et al. it is readily apparent that the arterial (aortic and carotid) baroreflexes are reset to function at the prevailing ABP of exercise. The blood pressure of exercise is the result of the hemodynamic (cardiac output and TPR) ...

The artificial heart (AH) is devoid of physiologic connections to the recipient's native feedback control loops. Control of an AH can be either passive or dynamic. Passive intrinsic control provides limited AH response to physiologic demands. Dynamic control requires the sensing of metabolic and hemodynamic signals and their incorporation into ...

The establishment and monitoring of anticoagulation before, during, and after interventional and invasive procedures are crucial responsibilities. However, few prospective studies exist to rationally guide us in how and when to "act" in response to ACT values in specific clinical situations. Definitive studies to reach a uniform and safe ++approach ...

BACKGROUND: Since the pathogenesis of coronary heart disease (CHD) has its origins in childhood, researchers have increasingly evaluated CHD risk factors in youth. In this study we examined the hypothesized behavioral risk factor of cardiovascular responsivity as a predictor of very young children's resting cardiovascular functioning 2 1/2 years later. ...

1. In the conscious rat, cardiovascular responses to intrathecally (i.t.) administered neuropeptide gamma (NP gamma) were studied prior to and after the i.t. pretreatment with selective antagonists at NK1 ((+/-)-CP 96345 and RP 67580), NK2 (SR 48968) and NK3 (R 486) receptors. Pretreatment with a mixture of peptidase inhibitors (phosphoramidon, ...

Bicycling is frequently recommended as a form of aerobic exercise to reduce the risk of cardiovascular events, yet it is not without safety risks. The recent accidental death of locally-known cyclist has raised safety concerns of recreational cycling on Arkansas roads. This article summarizes cycling accident statistics obtained from the ...

The belief that color may have many varied effects on the human organism has been well-established. Very little, however, has been done to look at responses to color during exercise. 15 subjects performed three maximal graded treadmill tests, once in each of three different colored environments. Five physiological and one ...

Change in circulating blood volume by bed rest has been suggested to effect on many cardiovascular responses after bed rest including orthostatic intolerance and exercise performance. However, there is a lack of consensus on effect of renin-angiotensin-aldosterone system (RAAS) on baseline heart rate and blood pressure during bed rest, although ...

CPX testing allows for the objective assessment of aerobic capacity, anaerobic threshold, and the ventilatory response to exercise in patients with cardiovascular disease. These results can be used to assess severity of disease, its progression over time, prognosis, candidacy for transplantation, and response to therapy. CPX testing can also serve ...

The nucleus of the solitary tract (NTS) was systematically explored in the alpha-chloralose-anesthetized rat for sites that elicited changes in mean arterial pressure (MAP) and heart rate (HR) during microinjections (20 nl) of phosphate-buffered saline (PBS; pH 7.2-7.4) or NaCl solutions containing various concentrations of NaCl (104-326 mM). Decreases in ...

1. The main role of the nucleus tractus solitarius (NTS) as a relay center for viscerosensory fibers from the periphery and for pathways from modulatory autonomic centers is reviewed on the basis of its anatomical connections and neurotransmitter content. 2. Vasopressin is present in the entire neuroaxis and is of ...

Examining the hemodynamic responses to exercise provides a unique opportunity to analyze and integrate cardiovascular physiology because more is learned about how a system operates when it is forced to perform than when it is idle. We designed a laboratory exercise that examines the cardiovascular responses to exercise in a ...

The relationship between HP and haemodynamic changes is an area which until now has been largely uninvestigated as can be seen from the small amount of material published on this theme. The reasons for this indifference are mainly due to the low extracorporeal flow using during HP. The experiment with ...