Couples who share a bed get better sleep resulting in improved mental health, memory and problem-solving skills, according the to results of a new study.
In German experiments, couples sleeping together were shown to have longer and less disrupted periods of rapid-eye movement (REM) sleep.
REM sleep – the fourth stage of sleep, associated with vivid dreams – has been linked to emotion regulation, memory consolidation, social interactions and creative problem solving.
Couples that spent the night in the same bed showed synchronisation of what is known as ‘sleep architecture’ – the transition between the four different stages of sleep.
Researchers also found that a strong relationship between partners was positively associated with synchronised sleep patterns, when they slept in the same bed together.
Couples that spend the night in the same bed show increased REM sleep and synchronisation of what is known as ‘sleep architecture’. Researchers conducted the study among 12 young, healthy, heterosexual couples who spent four nights in their ‘sleep laboratory’ in Germany
‘Sleeping with a partner might actually give you an extra boost regarding your mental health, your memory, and creative problem-solving skills,’ said Dr Henning Drews at the Centre for Integrative Psychiatry (ZIP) in Schleswig-Holstein, northern Germany.
‘One could say that while your body is a bit unrulier when sleeping with somebody, your brain is not.’
In many countries, sharing a bed with a partner is common practice, but research investigating the relationship between bed sharing and sleep quality is scarce.
Most research that had previously compared couples sharing a bed to sleeping individually had only measured body movements.
Researchers at ZIP therefore wanted to learn more about ‘sleep architecture’ and brain activity in couples during their slumber.
They recruited 12 young, healthy, heterosexual couples who spent four nights in their ‘sleep laboratory’.
The research team measured sleep using polysomnography, an exact and comprehensive sleep test study that captures sleep information using various factors.
Participants were fitted with polysomnography equipment – which measures brain waves to movements, respiration, muscle tension, movements, heart activity and more – when they slept alone from their partner and when they slept apart.
Couples synchronise their sleep patterns when sleeping together. This synchronisation, which is not linked to the fact that partners disturb each other during the night, is positively associated with relationship depth
Additionally, the participants completed questionnaires designed to measure relationship characteristics, such as relationship duration, degree of ‘passionate love’ and relationship depth.
REM sleep was both increased and less disrupted in couples sleeping together compared to when they slept individually, they found.
Couples with a strong relationship depth also showed synchronised sleep patterns when sleeping together.
This synchronisation, which was not linked to the fact that partners disturb each other during the night, was positively associated with relationship depth.
In order words, the higher participants rated the significance of their relationship to their life, the stronger the synchronisation with their partner.
The research team said sleeping together enhances and stabilises REM sleep, which in turn improves our social interactions and reduces emotional stress.
ZIP researchers suggest a ‘positive feedback loop’ happening at night for couples in bed together.
Sleeping together enhances and stabilises REM sleep, which in turns improves our social interactions and reduces emotional stress.
Although the research team didn’t specifically measure these possible effects, Dr Drews said that ‘since these are well known effects of REM sleep, it is very likely that they would be observed if testing for them’.
Interestingly, researchers found an increased limb movement in couples who share the bed, although these movements did not disrupt sleep architecture.
Dr Drews and his team acknowledged the limitations of the study, including the fact that the participant sample was restricted to young and heterosexual couples.
‘The first thing that is important to be assessed in the future is whether the partner-effects we found – promoted REM sleep during co-sleep – are also present in a more diverse sample – e.g., elderly, or if one partner suffers from a disease,’ he said.
The study has been published in the journal Frontiers.
THE FOUR STAGES OF SLEEP
Sleep is generally separated in four stages. The first three of these are known as ‘non rapid eye movement’ or NREM sleep.
The last stage is known as rapid eye movement or REM sleep.
A typical night’s sleep goes back and forth between the stages.
Stage 1: In the first five minutes or so after dropping off we are not deeply asleep.
We are still aware of our surroundings but our muscles start to relax, the heart beat slows down and brainwave patterns, known as theta waves, become irregular but rapid.
Although we are asleep during Stage 1, we may wake up from it feeling like we didn’t sleep at all.
After around five minutes our bodies move into stage two.
Stage 2: This is when we have drifted into sleep, and if awakened would know you we been asleep. Waking up is still fairly easy.
This stage is identified by short bursts of electrical activity in the brain known as spindles, and larger waves known as K-complexes, which indicate that the brain is still aware of what is going on around it before turning off to a sub-conscious level.
Heartbeat and breathing is slow, and muscles relax even further.
Our body temperature drops and eye movements stop.
Brain wave activity slows but is marked by brief bursts of electrical activity.
Stage 3: Stage 3 non-REM sleep is the period of deep sleep that we need to feel refreshed in the morning.
It occurs in longer periods during the first half of the night.
Our heartbeat and breathing slow to their lowest levels during sleep and brain waves become even slower.
Our muscles are relaxed and it people may find it difficult to awaken us.
The body repairs muscles and tissues, stimulates growth and development, boosts immune function, and builds up energy for the next day.
REM sleep: REM sleep first occurs about 90 minutes after falling asleep.
Our eyes move rapidly from side to side behind closed eyelids.
Mixed frequency brain wave activity becomes closer to that seen in wakefulness.
Our breathing becomes faster and irregular, and heart rate and blood pressure increase to near waking levels.
Most dreaming occurs during REM sleep, although some can also occur in non-REM sleep.
Arm and leg muscles become temporarily paralysed, which prevents us from acting out our dreams.
As we age, we sleep less of your time in REM sleep.
Memory consolidation most likely requires both non-REM and REM sleep.
Source: US National Institutes of Health