Heart rate

heartbeatresting heart ratemaximum heart raterateventricular rateBPMHeartheart-ratepulseTarget Heart Rate
Heart rate is the speed of the heartbeat measured by the number of contractions (beats) of the heart per minute (bpm).wikipedia
540 Related Articles

Tachycardia

fast heart rateincreased heart raterapid heart rate
Tachycardia is a fast heart rate, defined as above 100 bpm at rest. Central nervous system depressants or sedatives decrease the heart rate (apart from some particularly strange ones with equally strange effects, such as ketamine which can cause – amongst many other things – stimulant-like effects such as tachycardia). In general, increased levels of the thyroid hormones (thyroxine(T4) and triiodothyronine (T3)), increase the heart rate; excessive levels can trigger tachycardia.
Tachycardia, also called tachyarrhythmia, is a heart rate that exceeds the normal resting rate.

Bradycardia

slow heart rateslowed heart ratebradyarrhythmia
Bradycardia is a slow heart rate, defined as below 60 bpm at rest.
Bradycardia is a condition typically defined wherein an individual has a resting heart rate of under 60 beats per minute (BPM) in adults.

Heart arrhythmia

arrhythmiacardiac arrhythmiaarrhythmias
When the heart is not beating in a regular pattern, this is referred to as an arrhythmia.
A heart rate that is too fast – above 100 beats per minute in adults – is called tachycardia and a heart rate that is too slow – below 60 beats per minute – is called bradycardia.

Pulse

pulse ratepulsationheartbeat
It is usually equal or close to the pulse measured at any peripheral point.
The heart rate may be greater or lesser than the pulse rate depending upon physiologic demand.

Cardiovascular centre

cardiovascular center
Nervous influence over the heartrate is centralized within the two paired cardiovascular centres of the medulla oblongata.
The cardiovascular centre is a part of the human brain responsible for the regulation of the rate at which the heart beats through the nervous and endocrine systems.

Exercise

physical exercisephysical activityexercising
Activities that can provoke change include physical exercise, sleep, anxiety, stress, illness, and ingestion of drugs.

Norepinephrine

noradrenalinenoradrenergicNE
The accelerans nerve provides sympathetic input to the heart by releasing norepinephrine onto the cells of the sinoatrial node (SA node), and the vagus nerve provides parasympathetic input to the heart by releasing acetylcholine onto sinoatrial node cells.
In the rest of the body, norepinephrine increases heart rate and blood pressure, triggers the release of glucose from energy stores, increases blood flow to skeletal muscle, reduces blood flow to the gastrointestinal system, and inhibits voiding of the bladder and gastrointestinal motility.

Depressant

depressantsdownerscentral depressant
Central nervous system depressants or sedatives decrease the heart rate (apart from some particularly strange ones with equally strange effects, such as ketamine which can cause – amongst many other things – stimulant-like effects such as tachycardia).
When depressants are used, effects often include ataxia, anxiolysis, pain relief, sedation or somnolence, and cognitive/memory impairment, as well as in some instances euphoria, dissociation, muscle relaxation, lowered blood pressure or heart rate, respiratory depression, and anticonvulsant effects, and even complete anesthesia or death at high doses.

Medulla oblongata

medullabulbarmedullary
Nervous influence over the heartrate is centralized within the two paired cardiovascular centres of the medulla oblongata.
The medulla contains the cardiac, respiratory, vomiting and vasomotor centers and therefore deals with the autonomic functions of breathing, heart rate and blood pressure.

Bainbridge reflex

There is a similar reflex, called the atrial reflex or Bainbridge reflex, associated with varying rates of blood flow to the atria.
The Bainbridge reflex, also called the atrial reflex, is an increase in heart rate due to an increase in central venous pressure.

Vagus nerve

vagusvagalX
The accelerans nerve provides sympathetic input to the heart by releasing norepinephrine onto the cells of the sinoatrial node (SA node), and the vagus nerve provides parasympathetic input to the heart by releasing acetylcholine onto sinoatrial node cells.
This means that the vagus nerve is responsible for such varied tasks as heart rate, gastrointestinal peristalsis, sweating, and quite a few muscle movements in the mouth, including speech (via the recurrent laryngeal nerve).

Triiodothyronine

T3T 3 triiodothyronine (T3)
In general, increased levels of the thyroid hormones (thyroxine(T4) and triiodothyronine (T3)), increase the heart rate; excessive levels can trigger tachycardia.
It affects almost every physiological process in the body, including growth and development, metabolism, body temperature, and heart rate.

Sympathetic nervous system

sympatheticsympathetic nervesympathetic nerves
While heart rhythm is regulated entirely by the sinoatrial node under normal conditions, heart rate is regulated by sympathetic and parasympathetic input to the sinoatrial node. The normal SA node firing rate is affected by autonomic nervous system activity: sympathetic stimulation increases and parasympathetic stimulation decreases the firing rate.
For example, the sympathetic nervous system can accelerate heart rate; widen bronchial passages; decrease motility (movement) of the large intestine; constrict blood vessels; increase peristalsis in the oesophagus; cause pupillary dilation, piloerection (goose bumps) and perspiration (sweating); and raise blood pressure.

Autonomic nervous system

autonomicautonomous nervous systemautonomic functions
The normal SA node firing rate is affected by autonomic nervous system activity: sympathetic stimulation increases and parasympathetic stimulation decreases the firing rate.
The autonomic nervous system is a control system that acts largely unconsciously and regulates bodily functions such as the heart rate, digestion, respiratory rate, pupillary response, urination, and sexual arousal.

Sinoatrial node

sinus nodesinoatrialsinoatrial (SA) node
While heart rhythm is regulated entirely by the sinoatrial node under normal conditions, heart rate is regulated by sympathetic and parasympathetic input to the sinoatrial node. The normal resting heart rate is based on the at-rest firing rate of the heart's sinoatrial node, where the faster pacemaker cells driving the self-generated rhythmic firing and responsible for the heart's autorhythmicity are located.
Heart rate depends on the rate at which the sinoatrial node produces action potentials.

Cardiac cycle

heartbeatheart beatventricular systole
Heart rate is the speed of the heartbeat measured by the number of contractions (beats) of the heart per minute (bpm).
Heart rate

Cardiac pacemaker

pacemakerpacemaker cellscardiac pacemakers
The normal resting heart rate is based on the at-rest firing rate of the heart's sinoatrial node, where the faster pacemaker cells driving the self-generated rhythmic firing and responsible for the heart's autorhythmicity are located.
The rate at which these impulses fire controls the rate of cardiac contraction, that is, the heart rate.

Hypothermia

exposurehypothermiclow body temperature
The heart rate can be slowed by altered sodium and potassium levels, hypoxia, acidosis, alkalosis, and hypothermia.
As the temperature decreases, further physiological systems falter and heart rate, respiratory rate, and blood pressure all decrease.

Hypercalcaemia

hypercalcemiahigh blood calciumhigh blood calcium levels
High levels of calcium ions result in hypercalcemia and excessive levels can induce cardiac arrest.
Hypercalcemia can result in an increase in heart rate and a positive inotropic effect (increase in contractility).

Adrenal medulla

medullamedullary(medulla)
The catecholamines, epinephrine and norepinephrine, secreted by the adrenal medulla form one component of the extended fight-or-flight mechanism.
Notable effects of adrenaline and noradrenaline include increased heart rate and blood pressure, blood vessel constriction in the skin and gastrointestinal tract, smooth muscle (bronchiole and capillary) dilation, and increased metabolism, all of which are characteristic of the fight-or-flight response.

Parasympathetic nervous system

parasympatheticparasympathetic nerveparasympathetic nerves
While heart rhythm is regulated entirely by the sinoatrial node under normal conditions, heart rate is regulated by sympathetic and parasympathetic input to the sinoatrial node. The normal SA node firing rate is affected by autonomic nervous system activity: sympathetic stimulation increases and parasympathetic stimulation decreases the firing rate.
The M2 muscarinic receptors are located in the heart, and act to bring the heart back to normal after the actions of the sympathetic nervous system: slowing down the heart rate, reducing contractile forces of the atrial cardiac muscle, and reducing conduction velocity of the sinoatrial node and atrioventricular node. They have a minimal effect on the contractile forces of the ventricular muscle due to sparse innervation of the ventricles from the parasympathetic nervous system.

Stimulant

psychostimulantstimulantspsychostimulants
Central nervous system stimulants such as substituted amphetamines increase heart rate.
Common effects may include increased alertness, awareness, wakefulness, endurance, productivity, and motivation, arousal, locomotion, heart rate, and blood pressure, and a diminished desire for food and sleep.

Heart

cardiachuman heartapex of the heart
Heart rate is the speed of the heartbeat measured by the number of contractions (beats) of the heart per minute (bpm).
The heart beats at a resting rate close to 72 beats per minute.

Catecholamine

catecholaminescatecholamine synthesiscatecholamine systems
The catecholamines, epinephrine and norepinephrine, secreted by the adrenal medulla form one component of the extended fight-or-flight mechanism.
Some typical effects are increases in heart rate, blood pressure, blood glucose levels, and a general reaction of the sympathetic nervous system.

Nicotine

nicotine addictionnicotine sulfateaddicted to nicotine
Caffeine and nicotine are both stimulants of the nervous system and of the cardiac centres causing an increased heart rate.
The release of epinephrine (adrenaline) causes an increase in heart rate, blood pressure and respiration, as well as higher blood glucose levels.