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In a resting state the heart rate is
- adults 60 - 80 beats / min
- children 80 - 100 beats / min
- newborn babies up to 150 beats / min
Tachycardia
Tachycardia is an upward deviation of the heart rate (more than 100 heartbeats per minute).
Bradycardia
Bradycardia is a downward deviation of the heart rate (less than 50 heartbeats per minute).
How is the heart rate controlled?
The heart rate may be involuntary (see Why does the heart beat?), but it can be influenced by the autonomic nervous system. This adapts the heartbeat to the needs of the whole organism. The autonomic nervous system has an affect on:
- Heartbeat frequency
- Contraction strength
The autonomic nervous system is made up of two parts with opposite functions: the sympathetic nervous system and the parasympathetic nervous system. The sympathetic nervous system has an increasing effect on the heart rate and the parasympathetic nervous system (often referred to as the "vegetative" system) a decreasing effect.
ECG = electrocardiogram
The electrical impulses in the heart which - via the sinus node to the conduction system - give the heart muscles the order to contract, are spread to a certain extent over the whole body surface. They can be measured with the help of an ECG. The different strengths of the current reflect the electrical activity in the heart and can be used to diagnose heart function.
