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More attention needed for sleep-wake patterns in intensive care units

07 January 2008

Patients in intensive care units (ICU) often have seriously disturbed sleep-wake patterns. They do not necessarily sleep less, but they get half of their hours of sleep during the night and take several naps during the day. The more seriously ill a patient is, the more the pattern is disturbed, while a normal sleep-wake pattern and biorhythm is very important particularly at times like this. This has been revealed by UMCG PhD student Joost Gazendam.

Less than twenty percent of the sleep disruptions are caused by noise; abnormal light-dark patterns in the ICU play a greater role. ICUs are relatively dark during the day and too light at night. Having windows in an ICU certainly does not guarantee a more natural rhythm. Patients who are administered sleeping pills so that they can sleep through the night still sleep about as much during the day as patients who do not take sedatives.


Gazendam states that sleep-wake patterns should be improved by creating a better light-dark rhythm and limiting noise levels. The time of day should also be more clearly indicated by means of 24-hour clocks and television programmes. In addition, he states that more attention should be paid to the sleep-wake patterns of ICU patients.


Date and time: 7 januari 2008, 14.45

PhD student: J.A.C. Gazendam

Dissertation: To sleep or not to sleep. New insights in sleep-wake cycles and circadian rhythmicity in the intensive care unit

Promotores: prof. H.J. ten Duis and prof. J.H. Zwaveling

Faculty: Medical Sciences

Location: Aula Academiegebouw, Broerstraat 5, Groningen

Information: Joost Wessels, UMCG, Communications, tel. 050-361 4464 / 361 2200, e-mail:

Last modified:15 September 2017 3.37 p.m.
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