Correlated and uncorrelated regions in heart-rate fluctuations during sleep

Armin Bunde, Shlomo Havlin, Jan W. Kantelhardt, Thomas Penzel, Jörg Hermann Peter, Karlheinz Voigt

Research output: Contribution to journalArticlepeer-review

500 Scopus citations


Heart rhythm in the different sleep stages (deep, light, and REM sleep) that reflect different brain activities was studied for both healthy subjects and patients with moderate sleep disorder. It was observed that when the brain is very active as in the 'dream'-REM stage, the heart rates have a long-time memory, as in the wake phase. Contrary to this, in deep sleep the memory of the heart rates vanishes after a small number of beats that is below the order of the breathing cycle time. Finally, in light sleep, the heart rates seem to become uncorrelated as well, but the crossover occurs slightly above the breathing time.

Original languageEnglish
Pages (from-to)3736-3739
Number of pages4
JournalPhysical Review Letters
Issue number17
StatePublished - 23 Oct 2000


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