Variations in blood pressure
Blood pressure alters many times during the course of the day and night and adapts to the changing situations depending on numerous factors.
Such factors are, for example, body position (lying down or standing), breathing, psychological or physical stress, sleep or exertion. The lowest blood pressure values are recorded during sleep. High blood pressure values arise when the individual is excited or engaged in physical exertion.
Occasional high blood pressure due to exertion, stress, fear or other factors is natural, and the blood pressure will return to normal when these factors are removed. Excessive increases in blood pressure at times of such psychological or physical stress can, however, be the precursor of chronic high blood pressure.
The blood pressure level is determined in what is known as the circulatory centre of the brain on the basis of messages passed via the nerves to the brain. The blood pressure is adapted to the circumstances of the moment by means of changes in the intensity and frequency of the heartbeat (pulse), and through the diameter of the blood vessels, which is determined by the fine muscles on the blood vessel walls.