Sleep deprivation is a nationwide problem: 60% of Brits don't get enough sleep, according to a University of Hertfordshire survey. Continued poor sleep (less than 7 hours a night) can have significant effects on your wellbeing and new research even suggests that a poor night's kip could take its toll on a person's heart. The American Heart Association recently published new findings into the impact of sleep restriction and heart health and concluded that, under chronic conditions, abnormal sleep patterns may put people at higher risk of having cardiovascular disease.

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Sleep deprivation comes in many forms. While general feelings of sluggishness, dark circles and a lack of concentration are often blamed on poor sleep, some indications are less obvious. Here's how to spot the lesser-known signs that could mean you're not getting enough shut-eye:

1. You find it harder to say no

A lack of sleep could cause your self control to go out the window. A recent study at Clemson University discovered that people who don't get enough sleep have a higher risk of being impulsive or distracted and making poor decisions. June Pilcher, Clemson Alumni Distinguished Professor of psychology said:

"Our study explored how sleep habits and self-control are interwoven and how sleep habits and self-control may work together to affect a person's daily functioning."

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2. You keep forgetting where you've put your keys

For an event to become a memory (no matter if it's something small like remembering that you've run out of milk or something huge such as the birth of your first child) you need to acquire the memory, consolidate it in the brain and then have the ability to recall it in the future. Two of these functions occur when we're awake, but consolidation occurs when we're asleep. Studies have shown that sleep deprivation impairs both attention and working memory (long and short-term).

3. You're more accident prone

With lower concentration and a slower reaction time, your movement may be affected. A lack of sleep may also impair reflexes, balance and depth perception. Not to mention, getting six or fewer hours sleep each night triples a person's risk of driving-related accidents, according to the National Sleep Foundation.

4. You've got the sniffles

Colds may spread fairly easy, but missing out on sleep could make you more likely to succumb to the sniffles, with several studies linking poor sleep to lower immunity. A study in the Archives of Internal Medicine discovered those who got less than seven hours sleep a night were three times more likely to develop a cold than those who got eight or more. One explanation is that your immune system release cytokines (a protein involved in the regulation of sleep) when you're asleep. These proteins need to increase when you have an infection or inflammation in the body and a bad sleep could lead to fewer cytokines.

5. You become less interested in sex

If your sex drive isn't what it normally is, inadequate sleep could be to blame. Research found that those who sleep for five hours or less, might not only have lower energy and a lack of concentration, but a lower libido, too. While it might seem obvious that a poor sleep equals less motivation to have sex, it isn't necessarily the tiredness limiting your sex drive. A bad night's sleep may lower sex hormone levels, particularly in men. Other research suggests that poor sleep patterns could also affect sperm count.

6. Your mood is low

Continued, disrupted sleep may also mean you feel emotionally all over the place.Poor sleepers show less stables patterns of behaviour, according to Sleepio. People are also twice as likely to suffer the blues, compared to those who get sufficient amounts of sleep, reveals the Great British Sleep Survey.

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