The relationship between a night's sleep and subsequent daytime functioning in older poor and good sleepers.

ABSTRACT

Those suffering insomnia symptoms generally report daytime impairments. However, research has not assessed whether this relationship holds on a nightly basis, despite the strongly held belief that a night of poor sleep impairs mood and functioning the following day. The objective of this study was to test this relationship in a group of older poor sleepers with insomnia symptoms compared with good sleepers. This study utilized a within-subjects design to investigate day-to-day subjective daytime functioning and its relation to the previous night's sleep. Seventeen older individuals (mean age 67.5 years) were identified with a retrospective questionnaire and 2 weeks of sleep-wake diary to have poor sleep consistent with insomnia. Seventeen good sleepers (mean age 67.8 years) were selected using the same measures. Participants reported their beliefs about sleep and daytime functioning on the Dysfunctional Beliefs and Attitudes about Sleep Scale (DBAS-16). One week later they commenced a 14-day period of sleep-wake diaries and concurrent responses to a modified Daytime Insomnia Symptom Scale (DISS). Results showed significant night-to-day covariation between sleep efficiency and daytime functioning for individuals with poor sleep (r = 0.34), but not for good sleepers (r = 0.08). Those poor sleepers who held this covariation belief most strongly were those who subsequently showed this night-to-day relationship the most strongly (r = 0.56). This was not true for good sleepers. For those suffering insomnia, these findings demonstrate their belief that a poor sleep is followed by an impaired daytime, consistent with their experience.