How to sleep: The FIVE scary signs you’re not asleep for long enough REVEALED

Sleep is essential for growing muscle, repairing tissue, and synthesising hormones, among other functions, according to the National Sleep Foundation.

It is recommended adults between the ages of 26 and 64 get between seven and nine hours a night, while those over 65 need between seven and eight.

However, according to a recent study, Britons are not getting anywhere near enough sleep.

Research by Aviva Health Insurance, published earlier this year, found that 38 per cent of adults in the UK - approximately 20 million people - are falling short on the shut-eye.

“Sleep deprivation can cause harm to your body in the short term,” warned Hope Bastine, psychologist and SIMBA Sleep’s ‘Think Well Sleep Well’ ambassador.

“Over time, it can lead to chronic health problems and negatively impact your quality of life.”

She revealed the five health concerns that could be caused by a lack of snooze time.

Colds and flu

Not clocking up the hours asleep could leave you with a weakend immune system.

“When you’re asleep, your immune system produces protective cytokines and infection-fighting antibodies and cells,” said Bastine.

“It uses these to fend off foreign substances like bacteria and viruses. 

“At the same time, these cytokines and other protective substances also help you sleep, giving the immune system more energy to defend against illness. 

“If you’re not getting enough sleep, your immune system doesn’t have the same chance to rebuild its forces.  Studies show that if you don’t get enough sleep, it’s more likely that your body won’t be able to fend off invaders. 

“It may also take you longer to recover from illness.”

Problems getting pregnant

A lack of sleep could also cause fertility issues if you are a man.

“Men who get too little sleep may be damaging their fertility,” explained Bastine.

A 2013 study by the University of Southern Denmark discovered that young men who experienced disturbed sleep had sperm counts that were over a quarter lower than their counterparts who slept more.

She added: “Those who suffered disturbed sleep with less than six hours a night also had lower sperm quality.”

Sleep deprivation can affect women’s fertility too.

“A special hormone called leptin affects ovulation,” she said.

“Women need adequate sleep for proper leptin production. When leptin production is compromised, menstrual cycles can be disrupted.”

High blood pressure

Hypertension affects 16 million in the UK, and can raise your risk of stroke and heart failure - and not enough sleep may be to blame.

“People who are sleep deprived may be at higher risk of developing high blood pressure or worsening existing high blood pressure,” said Bastine. 

“It's thought that sleep assists your blood regulate stress hormones and helps your nervous system to remain healthy. 

“Over time, a lack of sleep could hurt your body's ability to regulate stress hormones, leading to high blood pressure.”

Affects your skin health

Sleep deprivation could have an ageing effect on skin, noted Bastine.

She explained: “Studies have shown sleep deprivation could cause your skin to age faster. 

“A good night's sleep can aid good skin health because when you’re sleep-deprived, your body makes more of the stress hormone cortisol. 

“Increased levels of cortisol can lead to heightened stress and inflammation in the body, harming your skin’s quality.”

Inflammation can in turn speed up the breakdown of collagen and hyaluronic acid, the molecules that give the skin its glow.

Weight gain

If you’re struggling to control your weight, it may be as simple as just spending more time in bed.

“The amount of rest you get each night doesn’t only affect your mood and productivity the next day,” explained Bastine.

“Researchers have found that sleep loss can also affect the basic metabolic functions. 

“A lack of sleep can slow down the metabolism contributing to weight management issues.”