[Spectral analysis of long-term blood pressure measurements in patients with sleep-related respiratory disorders].

Spectral analysis of long-term recordings of blood pressure is a convenient method to recognise and reveal the amplitude and periodicity of changes in blood pressure during sleep. The increased variability of nocturnal blood pressure in patients with sleep apnoea is mainly determined by two types of oscillating variations in blood pressure: 1. Oscillations in a low frequency range of 0.0-0.06 Hz associated with breathing disorders and consecutive arousals. 2. Oscillations in a higher frequency range of 0.2-0.5 Hz associated with three different patterns of breathing. Normal undisturbed breathing, regular snoring and ineffective breathing efforts during obstruction of the upper airways. Furthermore, the interaction between breathing or breathing disorder and arterial blood pressure is determined by the influence of the sleep stages.