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Science of sleep spotlight: Sleep loss affects our entire body

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In the past 10 or more years, research has proven that sleep deprivation or ‘Sleep Loss’ can have profound consequences on your physical mind and body health.

‘Sleep Loss’ is any time we manage to sleep less than 7 hours per night and studies suggest that sleep deprivation may have wide-ranging effects on the cardiovascular, endocrine, immune, and nervous systems.

With emerging new research showing good quality sleep protects your physical body, as well as your mind, our resident sleep and wellbeing expert, Natalie Pennicotte-Collier, explains what happens to your mind and body if you consistently have less than 6 hours sleep a night. In addition, our latest blog post also looks at the impact a poor-quality sleep routine can truly have on the health of our heart, immune system, fertility and long-term diseases, and explains how important it is to invest in our sleep wellbeing.

What are the surprising effect of sleep deprivation on the mind and body?

Sleep deprivation occurs when an individual’s biological sleep need is not met. In scientific studies, definitions vary, but sleep deprivation is typically considered having less than seven hours of sleep. We know from our recent Hypnos Sleep Survey that so many of us struggle to get a healthy seven hours a night with only 13% of people rating their sleep as an excellent 10 on a scale of 1-10. But maintaining a healthy amount of sleep protects your brain and mental wellbeing as well as every biological function in your physical body, so it’s crucial we’re all getting enough.

Is there a link between sleep loss and long-term disease, like Alzheimer's?

It’s proven that a lack of sleep will lead to an increased development of a toxic protein in the brain that is called beta-amyloid which is associated with Alzheimer's disease. It is true to say that prolonged wakefulness, say a period of 16hrs+ without deep sleep, is akin to very low-level brain damage and here’s why…

During our deep sleep at night, the brain is cleansed almost like a sewage system and this kicks in to high gear to wash away toxins, including the protein beta-amyloid via the brain’s glymphatic system which is 60% more active at night than when we’re awake. Therefore, ensuring there is ample time for you to reach the deep sleep phase during the night is crucially important in the defence against harmful levels of toxins. Not paying attention to good quality sleep will mean that more of that Alzheimer's-related protein will build up. The more protein that builds up, the greater your risk of going on to develop dementia in later life.

On a more positive note, good and healthy sleep, which is around 7 hours or more, doesn’t just aid the cleansing of toxins, it actually improves your mind and brain cognitive function too. Too little sleep will prevent your brain from being able to make new memories and shut down the part which commits new experiences to memory. In 1982, the cognitive scientist Carlyle Smith discovered the connection between sleep, learning and memory consolidation. Poor quality sleep makes it really hard for you to store information in your brain and also makes you more forgetful.

Does sleep loss have an impact on fertility?

One of the best things you can do for your fertility prospects is to regularly get a good night’s sleep and this is true for both men and women. Sleep deprivation affects the reproductive system in a few ways.

We know in particular that men who are sleeping just five to six hours a night have a level of testosterone which is that of someone ten years older in biological age. Therefore, meaning a consistent lack of quality sleep will age you by almost a decade in terms of that aspect of virility and wellness.

The same powerful negative effects of sleep loss of female endocrine and reproduction have also been shown in numerous studies. Women sleeping only around 5-6 hours per night show a 20% reduction in the follicle stimulating hormone (FSH) – a critical hormone for getting pregnant.

Don’t let something as simple as an affinity for late night TV or a potentially changeable work schedule prevent you from healthy fertility. Make the necessary sleep health changes and establish a strong healthy sleep pattern and get your circadian and hormonal rhythm back on track.

What are the links between poor sleep and our immune system?

A good sleep routine protects a healthy immune system and here’s why…as you stay awake for longer than 18 hours, your body starts to build up pro-inflammatory proteins like IL-6, a blood marker associated with chronic health conditions and heart disease. Your number of immune cells begins to decline as well, as your body is deprived of its opportunity to make more.

It is widely recognised that a lack of sleep impacts your immune system and makes your far more susceptible to common coughs or colds. In fact, you are four times more likely to catch a winter bug after just one week of short sleep duration – having 6 hours of sleep or less each night, in fact getting 8 hours a night makes you 200-300% less likely to catch a cold than someone sleeping just 5 hours.

Crucially our immune system is integral to the fight against cancer and after just one night of four to five hours of sleep, there is a 70% reduction in critical anticancer-fighting immune cells called natural killer cells. In fact, one night of only 4 hours sleep drops your natural cancer killing T cells by 70%!

A short sleep duration predicts your risk for developing numerous forms of cancer, including cancer of the bowel, prostate and breast.

A study in the International Journal of Cancer found a relationship between women's irregular work schedules and the rate of breast cancer. Researchers compared 1,200 women who had developed breast cancer between 2005 and 2008, with 1,300 women who did not have a cancer diagnosis. They found that the rate of breast cancer was 30 per cent higher for the women who had worked shifts and therefore endured an irregular sleep pattern and less sleep overall.

Women who had worked night shifts for at least four years, as well as those with fewer than three-night shifts per week (keeping them from ever fully adjusting to one schedule) were at the highest risk. Shift work has also been shown to increase the incidence of certain cancers in men too, for example; prostate cancer.

What about our heart health?

Maintaining a healthy amount of sleep is crucially protective of your cardiovascular system, blood pressure and overall heart health.

New research has found that sleep duration can influence a person's risk of a heart attack, regardless of other heart risk factors, including genetic ones.

We do know that a lack of sleep impacts your cardiovascular system because it’s during deep sleep at night that you receive the body’s most powerful form of natural blood pressure medication - your heart rate drops and in turn; your blood pressure goes down.

If you're not getting healthy sleep sufficient sleep - around 7 hours plus, you're missing out on that precious reboot of the cardiovascular system, and in turn; your blood pressure rises.

If you only have six hours of sleep or less on a regular basis, you are at an increased risk by 200% of having a fatal heart attack or stroke in your lifetime.

Without that daily reboot of good quality deep sleep, your blood pressure steadily rises, and your risk of heart attack, stroke, and even long-term heart disease skyrockets.

If you’re awake for longer than 18 hours, your heart doesn’t get its daily respite, and this can have lethal consequences. In fact, research has found that on the Monday after spring daylight saving time, when we lose an hour of sleep, there’s a 25 percent increase in heart attacks.

Conversely, during the Autumn Clock Change, when we gain an extra hour, there is a 21 percent reduction in heart attacks.

A fascinating large-scale study published by The European Heart Journal co-authored by Professor Francesco Cappuccino provides some of the strongest proof yet that sleep duration is a key factor when it comes to heart health and regardless of genetic risk profile, this holds true for everyone.

The researchers found that keeping sleep duration to 6–9 hours per night can reduce the risk of a first heart attack by 18% in those people with a "high genetic liability" for developing heart disease. It also revealed that those who slept less than 6 hours per night had a 20% higher risk of a first heart attack in comparison to those who slept 6–9 hours, but surprisingly those who slept more than 9 hours had a 34% higher risk.

Sleep loss seriously affects our short term and long-term health

By acknowledging the science of sleep and the vital role it plays in the health of our brain, heart, immune system and fertility we can use it to motivate us to really focus on improving our sleep health and sleep quality to at least 7 hours or more per night. In turn we can use this to understand how a regular, consistent good sleep pattern used in line with sleep advice, will help to keep your mind and body healthy. In fact, sleep is the best free health insurance there is!

With that in mind, we should all aim for between 7-9 hours’ sleep and rest each and every night and keep consistency each night of the week, going to bed at the same time and sticking to a regular wake-up time and routine each morning.

For tips and tricks on how to fall asleep better, improve your sleeping environment and sleep tips for the whole family, click here.


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