…YOUR SPOUSE WRECKING YOUR NIGHT'S SLEEP?
He snores like a warthog while she kicks like a camel. She's always freezing cold, while he complains of being too hot.
Every night, bedrooms turn into battlegrounds, with research suggesting half of all of our sleep disturbances in an average night are due to our partner.
Sleep is a precious commodity, with deprivation linked to a host of conditions such as diabetes, heart disease and depression. Last month, scientists at Yale University reported that a disrupted sleep pattern may lower immunity.
Here, the experts reveal the problems that could be disrupting you and your partner's sleep - and how to tackle them:
Tossing and turning
We all change sleeping position around 20 times a night, but men seem to shift around more than women, says Professor Jim Horne, director of Loughborough University's Sleep Research Centre.
'In one experiment, we placed movement sensors on men and women, and found that men move around twice as much in the night. And we saw that if the man is, say, twice as heavy as his partner, then whenever he turns he causes the mattress to spring up on her side, and she can actually be propelled quite far.'
Night movement is also increased when a person is unwell, adds Dr Tim Quinnell, of the Sleep Laboratory at Papworth Hospital, Cambridge: 'The symptoms of other illnesses, such as pain or asthma can sometimes be particularly troublesome at night.'
What can you do? Try to time your medication regimen, so that you are taking it up to an hour before bed. But if your partner's tossing or turning is due to insomnia, send them packing from the bedroom. 'It won't help either of you if they just lie there getting frustrated,' says Dr Stanley. 'They should go to read a book until they feel sleepy.'
Frequent trips to the loo
The urge to use the lavatory more than once a night, called nocturia, affects more than 15 million adults, says Julia Herbert, of the Bladder and Bowel Foundation.
In older men, this urge is frequently caused by an enlarged prostate, which presses on the bladder. In women, the condition is often linked to incontinence.
'Women are constantly worried about leaking, and so go to the loo many times during the day 'just in case',' says Julia Herbert. However, if the bladder does not regularly hold a large amount of liquid, then the muscular walls will begin to shrink. The organ then holds less liquid, causing women to regularly need the loo during the day and at night.
What can you do? Bladder training - increasing the time between trips to the loo - and pelvic floor exercises can help, as can cutting caffeine intake.
Sleep-walking and nightmares
Up to 7 per cent of adults regularly sleep-walk. 'Although a sleep-walker will have no memory of it the next morning, it can prove stressful for a partner,' explains Dr Andrew Cummin, director of the Imperial College Healthcare Sleep Centre.
Meanwhile, around 300,000 Britons suffer night terrors - an intense nightmare characterised by a sudden feeling of intense dread or fear.
'A person will wake up shrieking, but usually remember nothing about it the next day,' says Professor Horne. 'Night terrors can occur if someone has ever experienced a moment that is horrifyingly scary, such as a car accident.'
Both conditions are thought to be caused by the brain not properly switching out of sleep mode, says Dr Quinnell. 'These people wake from deep sleep, but they wake so quickly that parts of the brain are asleep while others are awake.'
What can you do? Anything that reduces the quality of your sleep, such as alcohol or stress, working just before bedtime, or even sleeping away from home, can act as a trigger for these 'parasomnias'. For sleep-walkers, lock any doors in the bedroom, says Dr Stanley, especially if you are in a friend's house or hotel.
If they do sleep-walk, avoid waking them, as this can make them disorientated, he adds. Just guide them gently back to bed. However, if there is the possibility of them coming to harm, always wake them. Night terrors may be linked to trauma, so seek psychological help, says Professor Horne.
A kick or elbow is a common hazard of sharing a bed. 'Every night our brain paralyses most of the muscles, to prevent us from acting out our dreams,' says Dr Cummin. 'It is a form of self-protection to make sure we don't injure ourselves. However, in some people this safety feature fails.'
The problem, known as rapid eye disorder movement, is thought to affect around 300,000 Britons and tends to strike men over 50.
For some people, these twitches occur throughout the night, a condition known as Periodic Leg Movement. This becomes more common with age - some estimates suggest up to four in ten people over the age of 65 suffer from it. A related condition, called restless legs syndrome, causes a tingly sensation in the limbs and also strikes at night.
These can occur as a side effect of some drugs such as antidepressants, antipsychotics, antihistamines, as well as iron deficiency.
What you can do? Seek help if your partner appears to be acting out their dreams, which will be characterised by movements in both arms and legs. In rare cases, Dr Cummin says, it can herald Parkinson's disease about 15 years before the development of other symptoms.
However, most cases can be easily treated - one treatment is the benzodiazepine drug Clonazepam, which acts as a muscle relaxant. Twitches and restless legs can be treated with a type of medication called a dopamine agonist.
Find your partner wants the light off before you, or you want to open the curtains earlier than they do?
Our body clocks are coordinated by a complex interaction of hormones and nerve pathways, and various genes can influence this.
For example, a study last December of 10,000 people found those with a variant of a gene called ABCC9, which is responsible for sensing energy levels in our cells, may need 30 minutes extra sleep in the morning to feel fully awake.
Added to this is the fact that some people take much longer to become 'fully-operational' first thing in morning. This is due to sleep inertia, Dr Stanley explains.
Most of us suffer from this for the first ten minutes after getting up, but in some people it takes up to two hours. Also, Professor Horne adds that women tend to need about 20 minutes more sleep than men, due to their brains carrying out more multi-tasking in the day.
What can you do? Negotiation is key, says Dr Stanley. 'If your partner is not a morning person, then just accept that you won't get any sense out of them until they've had two strong coffees.'
The nightly tug of war of the duvet is often precipitated by women complaining about being too cold. And they may have a point, explains Dr Stanley. 'Research suggests that men don't perceive temperature as sensitively as women, which is why they feel warmer.'
One theory for this is that women tend to have more blood circulating around their core organs, and less around their extremities such as their hands and feet, which are the body's temperature sensors.
In other cases, a woman can be the partner generating the most heat. A 2001 study found that women's body temperature rises by as much as one degree towards the end of their menstrual cycle. Hormonal changes during the menopause and pregnancy can also lead to a raised temperature.
What can you do? 'As a rule, your bedroom temperature should always be between 16 and 18 degrees Celsius,' says Dr Stanley.
Tooth grinding and snoring
Around one in ten Britons grind their teeth at night at some stage in life.
'Teeth-grinding is amazingly disruptive to the partner, due to the dreadful sound it makes,' says Professor Horne. Nearly a third of us snore, and this is consistently one of the biggest disruptions to couples' sleep, says Dr Cummin.
What can you do? Your dentist can provide you with a dental shield to wear at night that will protect the teeth from damage.
Alcohol increases snoring, as it relaxes the airways. Losing weight also often helps. Dr Quinnell suggests sewing a golf or tennis ball into a T-shirt at the base of the spine or wedging pillows to stop your partner rolling on to their back.