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Chronotropic Incompetence
Chronotropic incompetence (CI) is the inability of heart rate to increase as expected in response to exercise. The condition can be defined in different ways and occurs in various diseases. Sufferers have a higher risk of cardiovascular disease and early death. Definition In healthy people, cardiac output during exercise increases via a rise in both heart rate and stroke volume. When the heart rate does not rise sufficiently, this can lead to exercise intolerance. CI can be detected using a cardiopulmonary exercise test. People with CI have a higher risk of cardiovascular disease and early death. There are different ways to define CI. One common threshold is not being able to reach 80% of age-predicted maximal heart rate (APMHR), which is said to be 220 – age. Another definition is not being able to reach 80% of the expected heart rate reserve, that is, the difference between the individual's resting heart rate and APMHR. Incidence Chronotropic incompetence occurs in vari ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cardiopulmonary Exercise Test
A cardiac stress test is a cardiological examination that evaluates the cardiovascular system's response to external stress within a controlled clinical setting. This stress response can be induced through physical exercise (usually a treadmill) or intravenous pharmacological stimulation of heart rate. As the heart works progressively harder (stressed) it is monitored using an electrocardiogram (ECG) monitor. This measures the heart's electrical rhythms and broader electrophysiology. Pulse rate, blood pressure and symptoms such as chest discomfort or fatigue are simultaneously monitored by attending clinical staff. Clinical staff will question the patient throughout the procedure asking questions that relate to pain and perceived discomfort. Abnormalities in blood pressure, heart rate, ECG or worsening physical symptoms could be indicative of coronary artery disease. Stress testing does not accurately diagnose all cases of coronary artery disease, and can often indicate that it e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fight-or-flight Response
The fight-or-flight or the fight-flight-freeze-or-fawn (also called hyperarousal or the acute stress response) is a physiological reaction that occurs in response to a perceived harmful event, attack, or threat to survival. It was first described by Walter Bradford Cannon in 1915. His theory states that animals react to threats with a general discharge of the sympathetic nervous system, preparing the animal for fighting or fleeing. More specifically, the adrenal medulla produces a hormonal cascade that results in the secretion of catecholamines, especially norepinephrine and epinephrine. The hormones estrogen, testosterone, and cortisol, as well as the neurotransmitters dopamine and serotonin, also affect how organisms react to stress. The hormone osteocalcin might also play a part. This response is recognised as the first stage of the general adaptation syndrome that regulates stress responses among vertebrates and other organisms. Name Originally understood as the "figh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
2-day CPET
A 2-day CPET is a cardiopulmonary exercise test given on two successive days to measure the effect of post-exertional malaise (PEM) on a patient's ability to exercise. PEM is a cardinal symptom of myalgic encephalomyelitis/chronic fatigue syndrome and is common in long COVID as well. Background Several differences have been found between people with and without ME/CFS, including people with other diseases or who are sedentary. On the first test, people with ME/CFS exhibit lower performance and heart rate, and on the second test, performance is even lower, while for controls, it is the same or slightly better. The largest decrease is in anaerobic threshold, which signifies a shift from aerobic to anaerobic metabolism at a lower level of exertion, and is not influenced by effort. Peak power output, heart rate, and VO2max also decrease, and in ME/CFS, but effort and familiarity with the test may affect VO2max and power. Additionally, healthy people generally recover from a CPET ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Myalgic Encephalomyelitis/chronic Fatigue Syndrome
Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a disabling Chronic condition, chronic illness. People with ME/CFS experience profound fatigue that does not go away with rest, as well as sleep issues and problems with memory or concentration. The Pathognomonic, hallmark symptom is post-exertional malaise (PEM), a worsening of the illness which can start immediately or hours to days after even minor physical or mental activity. This "crash" can last from hours or days to several months. Further common symptoms include orthostatic intolerance, dizziness or faintness when upright and pain. The cause of the disease is unknown. ME/CFS often starts after an infection, such as infectious mononucleosis, mononucleosis. It can run in families, but no genes that contribute to ME/CFS have been confirmed. ME/CFS is associated with changes in the nervous and immune systems, as well as in energy production. Diagnosis is based on distinctive symptoms, and a differential diag ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Long COVID
Long may refer to: Measurement * Long, characteristic of something of great duration * Long, characteristic of something of great length * Longitude (abbreviation: long.), a geographic coordinate * Longa (music), note value in early music mensural notation Places Asia * Long District, Laos * Long District, Phrae, Thailand * Longjiang (other) or River Long (lit. "dragon river"), one of several rivers in China * Yangtze River or Changjiang (lit. "Long River"), China Elsewhere * Long, Somme, France People * Long (Chinese surname) * Long (Western surname) Fictional characters * Long (''Bloody Roar''), in the video game series * Long, Aeon of Permanence in Honkai: Star Rail Sports * Long, a fielding term in cricket * Long, in tennis and similar games, beyond the service line during a serve and beyond the baseline during play Other uses * , a U.S. Navy ship name * Long (finance), a position in finance, especially stock markets * Lòng, name for a laneway in Sh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Type-2 Diabetes
Type 2 diabetes (T2D), formerly known as adult-onset diabetes, is a form of diabetes mellitus that is characterized by high blood sugar, insulin resistance, and relative lack of insulin. Common symptoms include increased thirst, frequent urination, fatigue and unexplained weight loss. Other symptoms include increased hunger, having a sensation of pins and needles, and sores (wounds) that heal slowly. Symptoms often develop slowly. Long-term complications from high blood sugar include heart disease, stroke, diabetic retinopathy, which can result in blindness, kidney failure, and poor blood flow in the lower limbs, which may lead to amputations. A sudden onset of hyperosmolar hyperglycemic state may occur; however, ketoacidosis is uncommon. Type 2 diabetes primarily occurs as a result of obesity and lack of exercise. Some people are genetically more at risk than others. Type 2 diabetes makes up about 90% of cases of diabetes, with the other 10% due prima ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Autonomic Nervous System
The autonomic nervous system (ANS), sometimes called the visceral nervous system and formerly the vegetative nervous system, is a division of the nervous system that operates viscera, internal organs, smooth muscle and glands. The autonomic nervous system is a control system that acts largely unconsciously and regulates bodily functions, such as the heart rate, its Myocardial contractility, force of contraction, digestion, respiratory rate, pupillary dilation, pupillary response, Micturition, urination, and Animal sexual behaviour, sexual arousal. The fight-or-flight response, also known as the acute stress response, is set into action by the autonomic nervous system. The autonomic nervous system is regulated by integrated reflexes through the brainstem to the spinal cord and organ (anatomy), organs. Autonomic functions include control of respiration, heart rate, cardiac regulation (the cardiac control center), vasomotor activity (the vasomotor center), and certain reflex, reflex ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Obstructive Sleep Apnea
Obstructive sleep apnea (OSA) is the most common sleep-related breathing disorder and is characterized by recurrent episodes of complete or partial airway obstruction, obstruction of the respiratory tract#Upper respiratory tract, upper airway leading to reduced or absent breathing during sleep. These episodes are termed "apneas" with complete or near-complete cessation of breathing, or "hypopneas" when the reduction in breathing is partial. In either case, a fall in oxygen saturation (medicine), blood oxygen saturation, a disruption in sleep, or both, may result. A high frequency of apneas or hypopneas during sleep may interfere with the quality of sleep, whichin combination with disturbances in blood oxygenationis thought to contribute to negative consequences to health and quality of life. The terms obstructive sleep apnea syndrome (OSAS) or obstructive sleep apnea–hypopnea syndrome (OSAHS) may be used to refer to OSA when it is associated with symptoms during the daytime (e.g. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
β-adrenergic Receptors
The adrenergic receptors or adrenoceptors are a class of G protein-coupled receptors that are targets of many catecholamines like norepinephrine (noradrenaline) and epinephrine (adrenaline) produced by the body, but also many medications like beta blockers, beta-2 (β2) agonists and alpha-2 (α2) agonists, which are used to treat high blood pressure and asthma, for example. Many cells have these receptors, and the binding of a catecholamine to the receptor will generally stimulate the sympathetic nervous system (SNS). The SNS is responsible for the fight-or-flight response, which is triggered by experiences such as exercise or fear-causing situations. This response dilates pupils, increases heart rate, mobilizes energy, and diverts blood flow from non-essential organs to skeletal muscle. These effects together tend to increase physical performance momentarily. History By the turn of the 19th century, it was agreed that the stimulation of sympathetic nerves could cause dif ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Downregulation
In biochemistry, in the biology, biological context of organisms' regulation of gene expression and production of gene products, downregulation is the process by which a cell (biology), cell decreases the production and quantities of its cellular components, such as RNA and proteins, in response to an external stimulus. The complementary process that involves increase in quantities of cellular components is called upregulation. An example of downregulation is the cellular decrease in the expression of a specific Receptor (biochemistry), receptor in response to its increased activation by a molecule, such as a hormone or neurotransmitter, which reduces the cell's sensitivity to the molecule. This is an example of a locally acting (negative feedback) mechanism. An example of upregulation is the response of liver cells exposed to such xenobiotic molecules as Polychlorinated dibenzodioxins, dioxin. In this situation, the cells increase their production of cytochrome P450, cytochrome P ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
β-blockers
Beta blockers, also spelled β-blockers, are a class of medications that are predominantly used to manage abnormal heart rhythms ( arrhythmia), and to protect the heart from a second heart attack after a first heart attack (secondary prevention). They are also widely used to treat high blood pressure, although they are no longer the first choice for initial treatment of most people. Beta blockers are competitive antagonists that block the receptor sites for the endogenous catecholamines epinephrine (adrenaline) and norepinephrine (noradrenaline) on adrenergic beta receptors, of the sympathetic nervous system, which mediates the fight-or-flight response. Beta-adrenergic receptors are found on cells of the heart muscles, smooth muscles, airways, arteries, kidneys, and other tissues that are part of the sympathetic nervous system and lead to stress responses, especially when they are stimulated by epinephrine (adrenaline). Beta blockers interfere with the binding to the recep ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Norepinephrine
Norepinephrine (NE), also called noradrenaline (NA) or noradrenalin, is an organic compound, organic chemical in the catecholamine family that functions in the brain and human body, body as a hormone, neurotransmitter and neuromodulator. The name "noradrenaline" (from Latin '':wikt:ad-, ad'', "near", and '':wikt:ren, ren'', "kidney") is more commonly used in the United Kingdom and the rest of the world, whereas "norepinephrine" (from Ancient Greek :wikt:ἐπί, ἐπῐ́ (''epí''), "upon", and :wikt:νεφρός, νεφρός (''nephrós''), "kidney") is usually preferred in the United States. "Norepinephrine" is also the international nonproprietary name given to norepinephrine (drug), the drug. Regardless of which name is used for the substance itself, parts of the body that produce or are affected by it are referred to as noradrenergic. The general function of norepinephrine is to mobilize the brain and body for action. Norepinephrine release is lowest during sleep, rise ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
