"When we look at the data on a day-by-day basis, there seems to be a vicious cycle in which sleep affects next day relationship functioning, and relationship functioning affects the subsequent night's sleep," principal investigator Brant Hasler of the University of Arizona says in a statement.
"In this cycle, conflict with one's partner during the day leads to worse sleep that night, which leads to more conflict the following day. Although these results are preliminary due to the relatively small sample size and a subjective measure of sleep quality, the woman's perception of the relationship seems particularly important, as it impacts both her own and her partner's subjective sleep quality that night."
The study involved data from 29 heterosexual, co-sleeping couples who did not have children. Each completed sleep diaries for seven days and each partner was asked to record the quality of interactions with his or her partner six times a day.
Hasler says interventions directed at improving either quality of sleep or relationships may provide overall benefits, as the two directly impact each other. Couples should resolve disputes before going to bed and avoid confrontational discussions on a day when one or both of them had a bad night's sleep, Hasler says.
Hasler presented the findings at Sleep, the 23rd annual meeting of the Associated Professional Sleep Societies in Seattle.