Sleep Is Essential for Health

March is National Bed Month and this year’s theme is “Sleep is Essential for Health”.

Why is getting enough sleep important?

Getting the right amount of good quality sleep is essential for health. Sleep is the time when our body repairs and recharges before the next day. If we don’t get the right amount of sleep, or the sleep is poor quality or fragmented, then we will be unable to restore and repair our body which leads to poor health.

lady sleeping peacefully

Why is sleep so important for your health?

For a working aged adult, the recommended amount of sleep that you should get is 7-9 hours every day. Research suggests that there are negative health consequences if you get significantly less or significantly more than that. In fact, research suggests that consistently getting less than 6 hours sleep per night, or getting too much, shortens your lifespan compared to someone who gets 7-9 hours sleep per night.

How does sleep affect heart health?

Sleep is vital for a healthy cardiovascular system. When someone doesn’t get enough good quality sleep, they are a greater risk of heart disease, heart attacks and stroke. Fragmented sleep, such as that caused by sleep apnoea, has an especially harmful effect on heart health. Sleep apnoea is a condition where someone stops breathing during the night, and then wakes from sleep to take a big gasp of breath before falling back to sleep again. These sleep apnoea awakenings can happen hundreds of times during the night, and the person may not realise they are waking up as they are awake for such a short amount of time. The reason that sleep apnoea may increase the risk of heart attacks is because each awakening causes a repeated spike of heart rate and blood pressure, causing strain on the heart.

How does sleep affect our weight?

When we sleep, we regulate hormones that relate to what we want to eat and how much (ghrelin and leptin). If we don’t get enough sleep then these hormones can become unbalanced – we produce too little leptin and too much ghrelin. When we don’t produce enough leptin we tend to eat more food before we feel satiated (or full). When we produce too much ghrelin we feel hungrier than usual, meaning we may choose a bigger portion than we would otherwise do. In fact, people who report sleeping for less than 5 hours per night tend to eat an additional 300 calories per day compared to someone sleeping 7-8 hours. Also those calories are more likely to be less healthy food choices such as fatty and processed foods.

If you are not sleeping well you may be less incentivised to go to the gym because you are too tired, leading to weight gain. People who don’t get enough sleep tend to be at a higher risk of obesity and diabetes.

What is the link between sleep and cancer?

Not getting the right amount of good quality sleep may be a risk factor for developing certain types of cancer, although more research is needed to clarify which cancers are most affected and why. The fact that sleep affects so many aspects of our body’s health including our hormone production and immune system, means that is not surprising that poor sleep may affect how our body reacts to cancer. Some studies have found that people who did not get enough sleep were at a greater risk of developing stomach cancer, thyroid and head cancer, while getting too much sleep is a risk factor for developing liver and breast cancer.

Another important aspect of sleep that is linked to health is our circadian rhythm. Our circadian rhythm is our 24 hour clock that regulates things like when we feel sleepy or alert, when we produce digestive enzymes and when best we might be able to exercise. If we travel across timezones we will experience our circadian rhythm functioning at the wrong time – such as making us feel sleepy when we should be getting up. This is also known as jet-lag. When our circadian rhythm is not working for us in the right way and at the right times, it can lead to a number of problems.

People whose circadian rhythm is not correctly aligned to when they are sleeping and waking can find problems with their immune system and their hormone production. This is a common problem when people work shifts, and there is a body of evidence to suggest that shift work is linked to an increased risk of hormonal cancers.

Woman with black curly hair hiding under the duvet

Why does sleep affect your risk of developing dementia?

When we sleep, our brain does a nightly “spring clean”. One of these nightly jobs is to physically “wash away” amyloid plaques during our sleep. Amyloid plaques have been associated with Alzheimer’s disease. When people don’t get sufficient sleep, they can get a build up of amyloid plaques in the brain leading to increased risk of dementia.

How does sleep improve your immunity?

During sleep is when certain parts of our immune system are boosted. For example, we produce cytokines (associated with inflammation) during the night which are a vital part of our immune system – especially that involved with adaptive immunity. Adaptive immunity is how our body learns to recognise and fight off infections or viruses that we have seen before. 

How much sleep someone gets the night following a vaccine can affect how effective the vaccine is. For example, people who regularly don’t get at least 7 hours sleep per night tend to have a reduced vaccine effectiveness, as their body may not have slept for long enough to learn about how to fight the virus from the vaccine. Interestingly, the inflammation from cytokines, though vital for adaptive immunity, could harm our physical and mental health if it occurred while we were awake. Therefore it likely needs to happen when we are resting and asleep, and the melatonin we produce at night also helps to counteract the inflammation.

In addition to insufficient sleep likely affecting our adaptive immunity, not getting enough sleep may affect your likelihood of getting sick, In fact, studies have found that when people sleep less than 6 hours per night, they are at a higher risk of catching the common cold or the flu.

Sleep benefits for mental health

When someone is not sleeping well, they are more likely to have depression or anxiety. Similarly, if someone has depression or anxiety, they are more likely to have trouble sleeping. This link between the disorders is not surprising, since if you are not sleeping that is likely to make you sad and anxious. Also, if you are anxious or stressed you are likely to have trouble sleeping.

White alarm clock

5 tips to help improve your sleep

  1. You won’t sleep as well if your bedroom is not comfortable. Make sure that your mattress is supportive for your weight and that your pillow is right for your sleeping style. People who sleep on the side may need a deeper or more supportive pillow than those who sleep on their back. Also, heavier people may need a firmer mattress than lighter people to ensure optimal spinal support during the night.
  2. Also, bedroom temperature is important since we need it to be cool enough for our core body temperature to drop as we fall asleep, but not too cold that we feel uncomfortably cold. An ideal bedroom temperature for sleep is
  3. Have a regular bedtime and wake time 7 days per week. This will help to strengthen your circadian rhythm and help you fall asleep quickly and wake feeling refreshed. It is better for your health to have the right amount of sleep every day, rather than sacrificing sleep during the week and then trying to catch up on lost sleep at the weekends.
  4. Keep your bedroom as a place for sleep and relaxation. Ideally, keep mobile phones out of the bedroom as they can distract you and make you more alert instead of relaxed and cal and ready for bed.
  5. Speak to your doctor if you are struggling. There are certain medical conditions that may be affecting your sleep, such as sleep apnoea or a thyroid issue which may need treatment from your GP. Therefore, if you are really struggling with your sleep it is important to speak to your GP so that they can rule out any medical causes. Cognitive behavioural therapy for insomnia (CBT-I) is the gold standard treatment for insomnia. It is effective at helping someone learn how to become less anxious about not sleeping and teaches them how to fall asleep without stress.

Dr Lindsay Browning is the resident sleep expert for And So to Bed. She offers sleep therapy at Trouble Sleeping and is the author of the self-help sleep book, Navigating Sleeplessness.

Posted by Dr Lindsay Browning
17th March 2023

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