Heart rate

The human heart
Autonomic Innervation of the Heart – Cardioaccelerator and cardioinhibitory areas are components of the paired cardiac centers located in the medulla oblongata of the brain. They innervate the heart via sympathetic cardiac nerves that increase cardiac activity and vagus (parasympathetic) nerves that slow cardiac activity.
Effects of Parasympathetic and Sympathetic Stimulation on Normal Sinus Rhythm – The wave of depolarization in a normal sinus rhythm shows a stable resting HR. Following parasympathetic stimulation, HR slows. Following sympathetic stimulation, HR increases.
Heart rate (HR) (top trace) and tidal volume (Vt) (lung volume, second trace) plotted on the same chart, showing how heart rate increases with inspiration and decreases with expiration.
The various formulae provide slightly different numbers for the maximum heart rates by age.
Fox and Haskell formula; widely used.
At 21 days after conception, the human heart begins beating at 70 to 80 beats per minute and accelerates linearly for the first month of beating.
Wrist heart rate monitor
Heart rate monitor with a wrist receiver
ECG-RRinterval
In obstetrics, heart rate can be measured by ultrasonography, such as in this embryo (at bottom left in the sac) of 6 weeks with a heart rate of approximately 90 per minute.
Pulsatile retinal blood flow in the optic nerve head region revealed by laser Doppler imaging

Speed of the heartbeat measured by the number of contractions (beats) of the heart per minute (bpm).

- Heart rate
The human heart

476 related topics

Relevance

Skeletal formula of noradrenaline

Norepinephrine

Organic chemical in the catecholamine family that functions in the brain and body as both a hormone and neurotransmitter.

Organic chemical in the catecholamine family that functions in the brain and body as both a hormone and neurotransmitter.

Skeletal formula of noradrenaline
Norepinephrine degradation. Metabolizing enzymes are shown in boxes.
Norepinephrine (labeled "noradrénaline" in this drawing) processing in a synapse. After release norepinephrine can either be taken up again by the presynaptic terminal, or broken down by enzymes.
Schema of the sympathetic nervous system, showing the sympathetic ganglia and the parts of the body to which they connect.
Brain areas containing noradrenergic neurons.
Chemical structure of octopamine, which serves as the homologue of norepinephrine in many invertebrate species

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.

Sinoatrial node shown at 1. The rest of the conduction system of the heart is shown in blue.

Sinoatrial node

Group of cells known as pacemaker cells, located in the wall of the right atrium of the heart.

Group of cells known as pacemaker cells, located in the wall of the right atrium of the heart.

Sinoatrial node shown at 1. The rest of the conduction system of the heart is shown in blue.
Figure 2: Low magnification stained image of the SA node (center-right on image) and its surrounding tissue. The SA node surrounds the sinoatrial nodal artery, seen as the open lumen. Cardiac muscle cells of the right atrium can be seen to the left of the node, and fat tissue to the right.
Figure 3: Sinoatrial node action potential waveform, outlining major ion currents involved (downward deflection indicates ions moving into the cell, upwards deflection indicates ions flowing out of the cell).
Schematic representation of the atrioventricular bundle

The rate of action potentials produced (and therefore the heart rate) is influenced by the nerves that supply it.

Physical fitness is achieved through exercise, among other factors. Photo shows Rich Froning Jr. – four-time winner of "Fittest Man on Earth" title.

Physical fitness

State of health and well-being and, more specifically, the ability to perform aspects of sports, occupations and daily activities.

State of health and well-being and, more specifically, the ability to perform aspects of sports, occupations and daily activities.

Physical fitness is achieved through exercise, among other factors. Photo shows Rich Froning Jr. – four-time winner of "Fittest Man on Earth" title.
Playing sports such as lawn tennis is a common way to maintain/improve physical fitness. Image shows international tennis player Barbora Strycova.
Swimmers in competitive swimwear perform squats prior to entering the pool in a U.S. military base, 2011.
Ladies performing a common 19th-century fitness routine including climbing the underside of a ladder, balancing and gymnastics.

For aerobic exercise to be beneficial, it must raise the heart rate and cause perspiration.

Diagram of the rise and lower of blood 
 from a pulse.

Pulse

In medicine, a pulse represents the tactile arterial palpation of the cardiac cycle (heartbeat) by trained fingertips.

In medicine, a pulse represents the tactile arterial palpation of the cardiac cycle (heartbeat) by trained fingertips.

Diagram of the rise and lower of blood 
 from a pulse.
Pulse evaluation at the radial artery.
Recommended points to evaluate pulse
Front of right upper extremity
Arteries of the neck.

The heart rate may be greater or lesser than the pulse rate depending upon physiologic demand.

Heart

Muscular organ in most animals that pumps blood through the blood vessels of the circulatory system.

Muscular organ in most animals that pumps blood through the blood vessels of the circulatory system.

Human heart during an autopsy
Computer-generated animation of a beating human heart
The human heart is in the middle of the thorax, with its apex pointing to the left.
Heart being dissected showing right and left ventricles, from above
Frontal section showing papillary muscles attached to the tricuspid valve on the right and to the mitral valve on the left via chordae tendineae.
Layers of the heart wall, including visceral and parietal pericardium
The swirling pattern of myocardium helps the heart pump effectively
Arterial supply to the heart (red), with other areas labelled (blue).
Autonomic innervation of the heart
Development of the human heart during the first eight weeks (top) and the formation of the heart chambers (bottom). In this figure, the blue and red colors represent blood inflow and outflow (not venous and arterial blood). Initially, all venous blood flows from the tail/atria to the ventricles/head, a very different pattern from that of an adult.
Blood flow through the valves
The cardiac cycle as correlated to the ECG
The x-axis reflects time with a recording of the heart sounds. The y-axis represents pressure.
Transmission of a cardiac action potential through the heart's conduction system
Conduction system of the heart
The prepotential is due to a slow influx of sodium ions until the threshold is reached followed by a rapid depolarization and repolarization. The prepotential accounts for the membrane reaching threshold and initiates the spontaneous depolarization and contraction of the cell; there is no resting potential.
3D echocardiogram showing the mitral valve (right), tricuspid and mitral valves (top left) and aortic valve (top right).
The closure of the heart valves causes the heart sounds.
Cardiac cycle shown against ECG
Heart and its blood vessels, by Leonardo da Vinci, 15th century
Animated heart
Elize Ryd making a heart sign at a concert in 2018
The tube-like heart (green) of the mosquito Anopheles gambiae extends horizontally across the body, interlinked with the diamond-shaped wing muscles (also green) and surrounded by pericardial cells (red). Blue depicts cell nuclei.
Basic arthropod body structure – heart shown in red
The human heart viewed from the front
The human heart viewed from behind
The coronary circulation
The human heart viewed from the front and from behind
Frontal section of the human heart
An anatomical specimen of the heart
Heart illustration with circulatory system
Animated Heart 3d Model Rendered in Computer

The heart beats at a resting rate close to 72 beats per minute.

Medulla oblongata purple, part of the brain stem colored

Medulla oblongata

Long stem-like structure which makes up the lower part of the brainstem.

Long stem-like structure which makes up the lower part of the brainstem.

Medulla oblongata purple, part of the brain stem colored
Medulla oblongata (animation)
Medulla and parts (10-16) - (10) pyramid; (11) the anterior median fissure; (15) is the choroid plexus in the fourth ventricle; (13) olive and (7) the pons
Medulla-animated as it protrudes from the foramen magnum of the skull-base, after which it gives rise to the spinal cord.
Lobes
Cross section of the medulla (in red) and surrounding tissues.
Anteroinferior view of the medulla oblongata and pons.
Base of brain.
Diagram showing the positions of the three principal subarachnoid cisternæ.
Medulla oblongata
Micrograph of the posterior portion of the open part of the medulla oblongata, showing the fourth ventricle (top of image) and the nuclei of CN XII (medial) and CN X (lateral). H&E-LFB stain.

The medulla contains the cardiac, respiratory, vomiting and vasomotor centers, and therefore deals with the autonomic functions of breathing, heart rate and blood pressure as well as the sleep wake cycle.

MRI video of a teen's heart beating.

Cardiac cycle

Performance of the human heart from the beginning of one heartbeat to the beginning of the next.

Performance of the human heart from the beginning of one heartbeat to the beginning of the next.

MRI video of a teen's heart beating.
The cycle diagram depicts one heartbeat of the continuously repeating cardiac cycle, namely: ventricular diastole followed by ventricular systole, etc.—while coordinating with atrial systole followed by atrial diastole, etc. The cycle also correlates to key electrocardiogram tracings: the T wave (which indicates ventricular diastole); the P wave (atrial systole); and the QRS 'spikes' complex (ventricular systole)—all shown as color purple-in-black segments.
The Cardiac Cycle: Valve Positions, Blood Flow, and ECG
The parts of a QRS complex and adjacent deflections. Re the cardiac cycle, atrial systole begins at the P wave; ventricular systole begins at the Q deflection of the QRS complex.
A Wiggers diagram illustrate events and details of the cardiac cycle with electrographic trace lines, which depict (vertical) changes in a parameter's value as time elapses left-to-right. The ventricular "Diastole", or relaxation, begins with "Isovolumic relaxation", then proceeds through three sub-stages of inflow, namely: "Rapid inflow", "Diastasis", and "Atrial systole". (During the "Diastole" period, the "Ventricular volume" increases (see red-line tracing), beginning after the vertical bar at "Aortic valve closes" and ending with the vertical bar at R in the QRS complex). + The ventricular "Systole", or contraction, begins with "Isovolumic contraction", i.e., with the vertical bar at "A -V valve closes"; it ends with completing the "Ejection" stage at the bar at "Aortic valve closes". During "Ejection" stage, the (red-line) tracing of "Ventricular volume" falls to its least amount (see ejection fraction) as the ventricles pump blood to the pulmonary arteries and to the aorta.
Diastole (at right) normally refers to atria and ventricles at relaxation and expansion together—while refilling with blood returning to the heart. Systole (left) typically refers to ventricular systole, during which the ventricles are pumping (or ejecting) blood out of the heart through the aorta and the pulmonary veins.
CGI animated graphic of the human heart, sectioned, with motions and timing synced with the Wiggers diagram. The section shows: 1) the opened ventricles contracting once per heartbeat—that is, once per each cardiac cycle; 2) the (partly obscured) mitral valve of the left heart; 3) the tricuspid and pulmonary valves of the right heart—note these paired valves open and close oppositely. + (The aortic valve of the left heart is located below the pulmonary valve, and is completely obscured.) The (unsectioned) atria are seen above the ventricles.
Cardiac diastole: Both AV valves (tricuspid in the right heart (light-blue), mitral in the left heart (pink)) are open to enable blood to flow directly into both left and right ventricles, where it is collected for the next contraction.
Cardiac (ventricular) systole: Both AV valves (tricuspid in the right heart (light-blue), mitral in the left heart (pink)) are closed by back-pressure as the ventricles are contracted and their blood volumes are ejected through the newly-opened pulmonary valve (dark-blue arrow) and aortic valve (dark-red arrow) into the pulmonary trunk and aorta respectively.

Cardiac muscle is composed of myocytes which initiate their internal contractions without applying to external nerves—with the exception of changes in the heart rate due to metabolic demand.

Distilled (concentrated) alcoholic beverages, sometimes called “spirit” or "hard liquor", roughly eight times more alcoholic than beer

Depressant

Drug that lowers neurotransmission levels, which is to depress or reduce arousal or stimulation, in various areas of the brain.

Drug that lowers neurotransmission levels, which is to depress or reduce arousal or stimulation, in various areas of the brain.

Distilled (concentrated) alcoholic beverages, sometimes called “spirit” or "hard liquor", roughly eight times more alcoholic than beer
Xanax (alprazolam) 2 mg tri-score tablets

When depressants are used, effects often include ataxia, anxiolysis, pain relief, sedation or somnolence, and cognitive or memory impairment, as well as in some instances euphoria, dissociation, muscle relaxation, lowered blood pressure or heart rate, respiratory depression, and anticonvulsant effects.

Schematic illustration showing the sympathetic nervous system with sympathetic cord and target organs.

Sympathetic nervous system

One of two divisions of the autonomic nervous system, along with the parasympathetic nervous system.

One of two divisions of the autonomic nervous system, along with the parasympathetic nervous system.

Schematic illustration showing the sympathetic nervous system with sympathetic cord and target organs.
The sympathetic nervous system extends from the thoracic to lumbar vertebrae and has connections with the thoracic, abdominal, and pelvic plexuses.
Scheme showing structure of a typical spinal nerve. 1. Somatic efferent. 2. Somatic afferent. 3,4,5. Sympathetic efferent. 6,7. Sympathetic afferent.
Sympathetic Nervous System – Information transmits through it affecting various organs.

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 innervation.

Autonomic nervous system

Division of the peripheral nervous system that supplies smooth muscle and glands, and thus influences the function of internal organs.

Division of the peripheral nervous system that supplies smooth muscle and glands, and thus influences the function of internal organs.

Autonomic nervous system innervation.
Autonomic nervous system, showing splanchnic nerves in middle, and the vagus nerve as "X" in blue. The heart and organs below in list to right are regarded as viscera.
Function of the autonomic nervous system
A flow diagram showing the process of stimulation of adrenal medulla that makes it release adrenaline, that further acts on adrenoreceptors, indirectly mediating or mimicking sympathetic activity.

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.