Over the years, researchers have studied sleep and have disclosed several benefits beyond the obvious providing rest for the body. They have also pointed out that it’s not just about sleeping, but length of time, temperature, position, foods and other factors can contribute to getting the best out of sleep time and reaping its numerous benefits. Recent studies have focused on how what one wears to sleep may affect his/her sleep and according to an international study by the U.S. National Sleep Foundation, sleeping in the nude has been shown to have numerous benefits. Experts revealed why ditching pyjamas is the best.
For a good night’s sleep
Sleep experts agree it’s important to keep cool at night as your body (or ‘core’) temperature needs to drop by about half a degree for you to fall asleep.
The brain, driven by your internal body clock, sends messages to the blood vessels to open up and release heat.
“Your core temperature is at its highest at 11:00p.m. and its lowest at 4:00a.m,” said Dr Chris Idzikowski, author of ‘Sound Asleep: The Expert Guide To Sleeping Well.’
“If anything prevents that decline in temperature, the brain will wake itself up to see what’s going on, meaning you’ll struggle to get to sleep or you’ll have disturbed sleep.
“The advantage of sleeping naked is it’s easier for the body to cool and maintain the lower temperature the brain wants to achieve,” he said.
Experts also agree that if you’re wearing lots of bedclothes, it’s going to be more difficult to regulate your temperature. They advise to wear the least one can get away with.
Disrupted sleep from being too hot doesn’t just mean you’ll get less sleep overall, but it might mean less deep sleep which is the most restorative type. Deep sleep is key for memory consolidation and the production of growth hormone which is important for cell repair and growth.
Though it’s important not to get too hot at night, it is important to make sure you have warm hands and feet. That’s because for your temperature to lower to the level that triggers sound sleep, your body needs to lose excess heat.
It does this by sending blood to the vessels near skin — in particular, those on the hands and feet — where heat is lost through the skin surface.
However, as Professor Foster explains, if your hands and feet are cold, the blood vessels next to the skin constrict and reduce blood flow in an effort to keep warm and stop heat escaping.
This in turn means your core temperature won’t be able to drop so easily.
A 2008 study by the Netherlands Institute for Neuroscience demonstrated the importance of body temperature in sleep.
Volunteers slept wearing thermosuits, allowing researchers to manipulate their skin temperature without altering core temperature.
The team found that when skin temperature was raised by just 0.4°C, the volunteers were significantly less likely to wake in the night.
In elderly volunteers, the effect was pronounced: the 0.4°C rise almost doubled the proportion of deep sleep and decreased the risk of waking too early from 50 per cent to four per cent.
Warming the skin caused blood vessels in the extremities to widen, so heat could be lost more easily.
In other words, to fall asleep easily, you need to be warm enough that your blood vessels won’t constrict, but not so hot that your body can’t cool down.
To ensure body temperature drops sufficiently, swap bed socks for a hot water bottle, says Dr Idzikowski.
“Bed socks don’t allow you to lose heat from your feet, so you’ll end up too hot,” he says.
Your bed partner can also be helpful for regulating your body temperature.
“If you’re cold, you can snuggle up to them and once you’re warm, you can move away,” said Professor Foster.
There is an increasing focus on brown fat, a type of tissue in the body that may protect against weight gain. While ordinary body fat piles on when we eat more calories than we burn, brown fat seems to burn excess calories to generate heat.
Babies have lots of brown fat — they need it to keep warm — but studies have shown there are small amounts in the necks of adults too. Experts believe that certain activities could switch on this fat, potentially helping to burn calories at a greater rate.
In a U.S. study in the journal Diabetes, researchers found that sleeping in a cold bedroom could activate brown fat in adults.
Five healthy young men slept in climate-controlled bedrooms for four months. For the first month, the room was kept at 24°C, then it was lowered to 19°C, then it went back to 24°C and for the last month raised to 27°C.
They ate the same amount of calories and their calorie expenditure and insulin sensitivity — how much insulin the body needs to keep blood sugar levels stable — were measured each day.
The results were striking. After four weeks sleeping at 19°C, the men had almost doubled their volumes of brown fat.
Tests showed they burned more calories throughout the day when their bedroom was cooler (though not enough to lose weight) and their insulin sensitivity had also improved.
Senior author, Francesco S. Celi, said the study showed that over time, sleeping in a cold bedroom could lessen the risk of diabetes.
Michael Symonds, professor of Developmental Physiology at the University of Nottingham and an expert on brown fat, says sleeping naked may be beneficial.
“Brown fat can produce 300 times more heat than any other body organ, meaning if you can keep it activated for a prolonged amount of time you’d be less likely to lay down excess energy.
“So, anything you can do to try to activate it, such as lowering the thermostat and sleeping in the cold, may be of benefit,” he said.
But room temperature shouldn’t be below a level at which you feel comfortable, otherwise you won’t sleep.
People who tend to feel hot at night and like to sleep naked, may have a high amount of brown fat, which causes them to feel warmer than others.
Lower blood pressure
If you share a bed with a partner, going nude is known to generate a generous boost of oxytocin, a hormone that provides numerous health benefits.
“Oxytocin release is triggered by closeness, particularly skin-to-skin contact,” says Dr Kerstin Uvnas-Moberg, a physiologist at the Swedish University of Agricultural Sciences and an expert on oxytocin.
“Sensory nerves on the skin send impulses to the brain, triggering the release.
“When a baby is placed on its mother’s chest, the blood in mother and child starts to pulse with oxytocin,” he said.
Oxytocin has a protective effect on the heart, as it lowers blood pressure. It also boosts the immune system and reduces anxiety.
“But it only works if skin-on-skin touching is something you’re happy with,” he added.
Boost your love life
People who sleep naked have happier love lives, according to a survey of 1,000 British adults by a bedsheet company.
The study found 57 per cent of nude sleepers were happy with their relationship, compared with 48 per cent of pyjama wearers and 43 per cent of nightie wearers (onesie wearers were just 38 per cent).
Sleeping naked has also been discovered to be a good strategy for those with body image issues.
You can slip under the sheets and then take your clothes off, and then you can be touched, even if you don’t want to be looked at.
Wearing nothing to bed can help women avoid developing yeast infections, such as thrush, says Austin Ugwumadu, a consultant gynaecologist.
“Thrush loves warm, restricted environments. So, wear something loose or preferably nothing at all.
“If you wear something tight, it means less air gets to the area and you’re more likely to sweat, which can cause irritation,” he said.
For healthy sperm
It’s long been suspected that the underwear men use and the positions they hold their bodies in can affect sperm quality, and now new research has backed up the notion that men should be free in the interest of having children.
According to a recent study, men who wore boxer shorts during the day and nothing to bed had significantly lower levels of damaged DNA in their sperm compared to those who wore tight underpants during the day and at night.
“Among men in the general population attempting pregnancy, type of underwear worn during the day and to bed is associated with semen quality,” said lead researcher Katherine Sapra of the US National Institute of Child Health and Human Development. “Reducing exposure for bed decreases DNA fragmentation; better semen quality parameters are observed in men wearing boxers during the day and none to bed.”
The study tracked 500 men over the course of a year, taking note of the underwear choices they made and the quality of their sperm.
The researchers found that those who slept naked and wore loose-fitting boxers during the day experienced 25 per cent less DNA fragmentation than those who opted for tight underwear like briefs. Although the sample size in the study was relatively small, it’s further evidence that adopting a more liberal approach when it comes to undergarments could pose considerable health benefits for men’s fertility.
Additional information from dailymail.com