The Impact of Shared Bedtimes on Sleep Quality
Couples who sleep together tend to have better quality sleep compared to those with differing bedtimes, according to a recent study. This research highlights how the timing of when each partner goes to bed can significantly affect their ability to fall asleep and the overall quality of their rest.
When one partner comes to bed after the other has already fallen asleep, it can lead to significant disruptions. The study found that individuals in this situation take almost 40 minutes longer to fall asleep than those who share a bedtime. Women were found to be more affected by these differences than men.
The research involved 859 married couples over an eight-year period and focused on how sleep is impacted during what researchers call the “fragile sleep window.” This is the time when the brain is still trying to transition into sleep and is highly sensitive to external stimuli such as light, sound, and movement.
Interestingly, people who go to bed later than their partner also experience poorer quality sleep. Researchers suggest that sharing a bedtime may foster a sense of emotional closeness between partners. When couples have different bedtimes, they may feel less connected, which can lead to stress and worse sleep.
The study, conducted by Seoul National University and published in BJPsych Open, focused on couples over the age of 60. It found that couples who shared a bedtime took no more than 24 minutes on average to fall asleep. In contrast, those whose partners came to bed while they were still trying to fall asleep took up to 63 minutes on average.
Researchers asked couples about their typical bedtime and how long it took them to fall asleep. This allowed them to determine if a partner’s bedtime fell within the time when the other was still trying to drift off.
Professor Ki Woong Kim, senior author of the study from Seoul National University, explained:
“The problem with different bedtimes comes when one partner climbs into bed while the other is still trying to fall asleep – the fragile 20 to 30 minute window before sleep is established. During that window, the brain is highly reactive to light, sound, and movement, and a partner getting into bed effectively resets the clock on sleep onset.”
He added:
“We always talk about sleep issues as an individual problem, but most of us don’t sleep as individuals – we share a bed with someone else. This means we need to look far more closely at mismatched bedtimes and how they affect sleep.”
Even for couples where one person goes to bed after the other is already fast asleep, having different bedtimes may make them less satisfied in their relationships, which could cause stress and sleeplessness.
People whose partner came to bed when they were drifting off also spent more of the night lying awake in bed – approximately 14 per cent of the night on average. Meanwhile, couples who shared a bedtime spent less than six per cent of the night awake.
Those whose partner came to bed when they were already fast asleep were not significantly affected in terms of sleep. However, night owls who went to bed to join their sleeping partner only took a little longer to fall asleep than those who shared a bedtime.
Despite this, these night owls had poorer sleep quality, which was judged using a questionnaire asking about things like how frequently they woke up during the night and whether they struggled to stay awake at key points during the day.
Over the eight-year period, the long-term effects of differing bedtimes were mostly felt by women. The study found that women whose partners came to bed later, while they were falling asleep, took about six minutes longer to fall asleep each year compared to the previous year.
Professor Kim concluded:
“When many people, especially older people, are concerned about their sleep, going to bed at the same time as your partner is an easy tactic to try, which can be implemented straight away without sleeping pills. It is just a small change which could make a significant difference.”
