Heart rate

The heart frequency or heart rate (abbreviated HF ) is the number of heart beats per period . The customary unit is min ^-1 or equivalent bpm ( English beats per minute ). The heartbeat rate is often equated with the pulse , which is strictly not correct, since the pulse comprises all the qualities of the pressure curve. The heart rate is both the quotient of cardiac output and stroke volume as well as the ratio of mean heart performance and average work of a heartbeat. The reciprocal of the heart rate is the mean duration of a complete heart cycle .

Heart rate in humans

The heartbeat rate in humans depends on the level of exercise, age and physical fitness. At rest, a newborn has a heart rate of around 120 beats per minute , while a 70-year-old has a frequency of around 70 beats per minute. The heartbeat rate in a healthy person is 50 to 100 beats per minute at rest. In patients with heart disease, these limit values ​​must be shifted according to the underlying cardiac disease.

The heart rate of a healthy person is subject to a variety of influences. A major part of the regulation is carried out by the autonomic nervous system in balance between the stimulating sympathetic and the dampening parasympathetic nervous system , and hormones circulating in the bloodstream , especially catecholamines , also play a role.

An increased heart rate is called tachycardia , and a decreased one is called bradycardia .

If the tachycardia is a normal reaction of the body during physical exertion, which enables it to adapt the cardiac output to the current requirements, an increase in the resting heart rate can indicate various diseases. In addition to primarily cardiac (in the heart) causes, there are also systemic (i.e. affecting the whole body) causes such as B. an incipient or manifest infectious disease in question. Psychological tension can also cause an increase in the heart rate by shifting the autonomic balance towards activation of the sympathetic nervous system.

The bradycardia may also have pathological causes. Physiologically, however, it occurs in competitive athletes , since the heart muscle increases in mass through exercise and can therefore transport more blood per heartbeat . The body's need for rest can thus be met at a lower heart rate, while at the same time, which is the point of the adjustment, the maximum resilience is higher. So was z. B. measured a resting heart rate of 28 beats per minute with the cyclist Miguel Indurain . For an average trained endurance athlete , a resting heart rate of 35 to 45 beats per minute is also lower than for an untrained person.

The maximum heartbeat frequency (also: maximum pulse ) is the number of heartbeats per minute that a person can achieve with the greatest possible physical exertion. The maximum heart rate is an individual variable and can be determined by ergometry . Rules of thumb for determining your own maximum heart rate (such as maximum heart rate = 220 - age in years), on the other hand, are not very useful, as they refer to statistical mean values ​​and the individual value can deviate from this by more than 30 beats.

Heart rate in animals

In mammals , the rule is that the larger the animal, the lower the heart rate. The total number of heartbeats in a mammal's life is around one billion . Humans are an exception: they can reach a maximum of almost four billion heartbeats.

The following table shows the heart rates for fully grown animals at rest, in addition the body weight for some species and the temperature at which the measurements were made for cold-blooded animals. Unless otherwise stated, the figures are based on Penzlin.

Mammals Blue whale (100 t ) 6th Elephant (4000 kg) 25-30 cow 55-80 Human (70 kg) 72 Cat (4 kg) 97 ± 27 giraffe 170 Rat (300 g) 350 Mouse (30 g) 600 Pipistrelle to 972 Etruscan shrew (2 g) 1000

Birds Turkey 93 Dove 192-244 buzzard 301 crow 342 canary 800-1000

Cold-blooded vertebrates Eels (13-16 ° C) 46-68 Frog (22 ° C) 35-40 Turtle (29 ° C) 11-37 Adder 40

Invertebrates Lugworm 13-22 Pond clam (18 ° C) 4-6 Octopus (octopus, 18 ° C) 32 Roman snail (15-20 ° C) 50 American lobster (18 ° C) 50-136 Asellus (a woodlouse) 180-200 Daphnia (20 ° C) 250-450 Red American marsh crayfish 120 Eurypelma californicum , a tarantula (~ 12 g) 21st little spiders 100 and more

Heart rate variability

The heart rate variability , also called "heart rate variability" (HRV from English heart rate variability ), defined as the ability of the heart rate of healthy people, to constantly change slightly. It is an expression of the body's various regulatory mechanisms that are required to maintain the stability of the cardiovascular system. The heart rate variability analysis tries to record these changes quantitatively and to make them usable for diagnostic and prognostic purposes. A change (mostly a reduction) of individual measures or components of the heart rate variability has been described for various diseases, so u. a. for high blood pressure and septic shock . The analysis of the heartbeat spread as well as its change under stress allows conclusions to be drawn about the type and severity of certain diseases. In particular , it has found acceptance as a criterion for assessing the prognosis of myocardial infarction . Sports medical research indicates limited suitability of HRV in training control . Heart rate variability can be trained and improved using biofeedback-based methods.

Application areas:

• Bloodless measurement of vagus nerve activity
• Autonomic disorders ( diabetes mellitus , coronary heart disease )
• Bloodless measurement of the anaerobic threshold
• Overtraining
• depression
• stress
• Physical and psychological stress
• Recovery time after competitions

See also

• Sinus tachycardia
• Heart rate monitor , EKG
• Bainbridge reflex
• Diving reflex

Web links

Wiktionary: Heart rate  - explanations of meanings, word origins, synonyms, translations

• Heart rate variability analysis
• Online heart rate calculator
• Introduction to heart rate analysis

Individual evidence

1. ^ Geigy Scientific Tables . Volume 5. ISBN 0-914168-54-1 , pp. 9-12.
2. ^ Guinness (Firm): Guinness world records 2004. Bantam Books, New York 2004, pp. "10-11" ( google.com [accessed December 11, 2019]).
3. ↑ Fat lot of good . In: Nature News . tape 533 , no. 7601 , May 5, 2016, p. 8 , doi : 10.1038 / 533008a ( nature.com [accessed December 11, 2019]).
4. ↑ Isaac Asimov : Of Time and Space . Schweizer Verlag-Haus, 1977, ISBN 978-3-7263-6189-1 .
5. ↑ ^{a b} Heinz Penzlin : Textbook of Animal Physiology . 7th edition. Spektrum Akademischer Verlag, Heidelberg 2009, ISBN 978-3-8274-2114-2 , p. 314-326 .
6. ↑ ^{a b c d e f} G. P. Dobson: On being the right size: heart design, mitochondrial efficiency and lifespan potential. In: Clinical and experimental pharmacology & physiology. Volume 30, Number 8, August 2003, pp. 590-597, ISSN  0305-1870 . PMID 12890185 .
7. ↑ SF Noujaim, E. Lucca, V. Muñoz, D. Persaud, O. Berenfeld, FL Meijler, J. Jalife: From mouse to whale: a universal scaling relation for the PR Interval of the electrocardiogram of mammals. In: Circulation. Volume 110, Number 18, November 2004, pp. 2802-2808, ISSN  1524-4539 . doi: 10.1161 / 01.CIR.0000146785.15995.67 . PMID 15505092 .
8. ^ Christopher D. Moyes, Patricia M. Schulte: Tierphysiologie . Pearson Studium, Munich 2008, ISBN 978-3-8273-7270-3 , pp. 424 ( limited preview in the Google book search - English: Principles of Animal Physiology . Translated by Monika Niehaus , Sebastian Vogel).
9. ↑ ^{a b c} Heinz Penzlin : Textbook of animal physiology . 7th edition. Spektrum Akademischer Verlag, Heidelberg 2009, ISBN 978-3-8274-2114-2 , p. 339-351 .