Sleep is our life support system.
We spend 1/3rd of our lives doing it.
It’s such an important aspect of our daily routine, yet many people do not fully understand the importance of getting enough sleep each night.
From physical and mental health benefits to improved productivity and memory retention, the reasons why we sleep are numerous.
So what happens when we sleep?
Sleep is a complex and fascinating process. Let’s take a closer look at what happens in our brains and bodies when we’re asleep.
1. Physical Changes in the Body
When we sleep, our bodies undergo a number of physical changes.
Our heart rate slows down, our breathing becomes more regular, blood pressure drops around 10-20% and our muscles relax.
These physical changes help us to enter into a state of deep relaxation and rejuvenation, allowing us to recharge and prepare for the day ahead.
2. Cognitive processes
At the same time, our brains are also undergoing a number of cognitive processes during sleep. You probably know this already but sleep is divided into several stages, including the light sleep, deep sleep, and rapid eye movement (REM) sleep stage.
Each lasting about 90 minutes or so.
During each stage, different processes are taking place in the brain, including memory consolidation and the processing of emotions and experiences.
When you deprive yourself of sleep you impair the brain’s ability to acquire new knowledge.
3. Memory Consolidation
One of the most important functions of sleep is memory consolidation.
During sleep, our brains process and consolidate memories from the day, helping us to retain important information.
Sleep is required before and after learning.
Without sleep, you can’t absorb new memories.
In an study published in Nature, they did an experiment where individuals were deprived just for one night of good sleep and they developed a 40% deficit in memory retention when compared to the control group.
There’s an important region in the brain called the Hippocampus, you can think of it as the information inbox of the brain. Sleep deprivation affects this area so you can’t commit new experiences to memory, it disrupts the connections.
Let’s talk about patient HM for a second.
He’s probably the best known patient in the history of neuroscience.
In 1953, he underwent a surgical procedure to treat his severe epilepsy.
The procedure involved the removal parts of his brain, including parts of his hippocampus, which is a region that is critical for the formation and retrieval of long-term memories.
After surgery, HM experienced a profound and lasting loss of memory and was unable to form new memories.
This is known as anterograde amnesia.
Bit of a side note but if you’re into good films like me then memento is a really good watch and was apparently partly inspired by the case of HM.
The case of Patient HM established the crucial role of the hippocampus in memory and provided insights into the relationship between brain structure and cognitive function, it was a landmark study in the history of neuroscience.
The study helped researchers understand the mechanisms of memory and the impact that damage to specific regions of the brain can have on cognitive function, leading to new treatments and therapies for conditions that affect memory.
4. Processing of Emotions and Experiences
In addition to memory consolidation, sleep also helps us to process emotions and experiences from the day.
During REM sleep, our brains process and consolidate emotions, helping us to regulate emotions and maintain a healthy mental state.
This is why it is so important to get enough sleep if you are dealing with stress or emotional challenges.
5. Physical and Mental Restoration
Sleep is also crucial for physical and mental restoration.
During sleep, our bodies repair and regenerate cells, helping us to maintain a healthy physical state.
At the same time, sleep helps to reduce stress and anxiety too.
The dangers of not sleeping enough.
A lack of sleep can lead to numerous health problems and negatively impact your life.
In recent years, numerous studies have have shed light on the dangers of not getting enough sleep.
More and more people are sleeping less than 6 hours per night, which is worrying.
Sleep deprivation has been known to increase the risk of depression and anxiety, harming productivity and cognitive performance.
It’s also important to realise that chronic sleep deprivation wreaks havoc on the immune system.
There is a growing body of evidence suggesting that sleep is critical for the immune system.
A meta-analysis of over 34,000 people provided the first the first global evidence linking sleep disturbance, sleep duration, and inflammation in adults.
They found that sleep deprivation and disturbances were associated with an elevated C-reactive protein or CRP level.
Let’s talk about CRP for a second.
CRP is an acute phase protein the liver produces in response to inflammation.
Healthy individuals have levels of less than 1 miligram per litre of blood.
In the hospital anything less than 5 is considered normal.
A marked increase in CRP typically indicates an underlying infectious process or tissue damage but it can also be elevated in chronic conditions like and chronically elevated CRP levels has been associated with cardiovascular disease, diabetes and various cancers.
The findings of this study suggest that sleep deprivation can impair the functioning of the immune system.
Another interesting study was one from UCLA which determined that partial sleep deprivation reduces natural killer cell activity in humans.
As part of their study they limited healthy adults to 4 hrs sleep for one night.
They measured their levels of natural killer cells (which identify foreign elements like cancer cells and destroy them)
They found that just one night of poor sleep caused a 70% drop in natural killer cell activity; think about what it could be after days or weeks of bad sleep.
What’s even more alarming is that a couple of years ago, the the International Agency for Research on Cancer (IARC) concluded that “night shift work” is “probably carcinogenic to humans”.
As a doctor who works nights, this isn’t ideal.
We also know that sleep is important for the maintenance of cardiovascular health and sleep deprivation has been linked to numerous heart problems including high blood pressure, high cholesterol, heart attacks, obesity, diabetes, and stroke.
Sleep deprivation is also linked to heart failure.
This is when the heart doesn’t pump enough blood to supply the body with the blood and oxygen that it needs to function properly.
An observational study of over 400,000 people found strong associations between sleeping problems and heart failure.
In that study, people who slept less than seven hours per night had an elevated risk of heart failure.
The studies we’ve talked about support the fact that that sleep plays a critical role in maintaining physical and mental health.
Here's 9 hacks that might help you get back in control of your sleep.
1. Stick to a regular schedule
One of the most important things you can do to improve your sleep is to stick to a regular sleep schedule.
Try to go to bed and wake up at the same time every day, even on weekends.
This will help your body to get into a routine and make it easier to fall asleep at night.
2. Create a Sleep-conducive environment
Another important factor in optimising your sleep is creating a sleep-conducive environment.
Make sure your bedroom is as dark as possible, quiet, and at a comfortable temperature. Around 18 degrees celsius is the optimum temperature for sleep.
3. Limit screen time
Exposure to screens before bed can interfere with your ability to fall asleep.
This is because the blue light from screens can suppress the production of melatonin, a hormone that regulates sleep.
Try to limit your exposure to screens for at least half an hour before bed.
4. Avoid caffeine and alcohol
Caffeine and alcohol can also interfere with your sleep.
Caffeine is a stimulant that can keep you awake and has a long half life, meaning that it takes several hours for it to be cleared from your system.
Alcohol might help some people to get to sleep quicker as it can induce drowsiness, it negatively affects sleep patterns.
Also try avoid eating too close to bedtime.
5. Analyse your sleep
Sleep trackers can be a helpful tool in optimising your sleep.
These devices can track your sleep patterns and give you valuable insights into your sleep habits.
When I wasn’t sleeping as much I looked at different options where I could analyse my sleep,
In the end I went for the Whoop band
I wanted to see how much sleep I was getting, the quality of my sleep and what adjustments I could make to improve my sleep.
6. Avoid sleeping tablets
Although they have a sedative effect, they don’t provide naturalistic sleep and have potentially dangerous side effects such as dependence and addiction.
Not a long-term fix.
7. Exercise
Simple one.
Exercising during the day can make you feel more tired when it comes to sleeping.
8. Create a wind down process
This is a great way of getting consistency with your routine.
I’ve started to do this recently and it’s helping.
I have a wind down alarm on my phone which helps to start the process of going to bed, like putting screens away from view, shutting the curtains and brushing your teeth.
Showering before bed can also help you sleep better as it cools your body temperature through a vasodilatory effect.
9. Avoid napping
20 minute naps are not bad for you, the science actually suggests that we may have been designed to sleep biphasically, rather than monophasically, supporting a siesta style schedule. Monophasically refers to the one long stretch of sleep we usually get at night.
If however you are struggling with sleep at night, the best thing to do is not to nap during the day.
Instead, try to build up sleepiness so that you give yourself the best chance of falling asleep easily and then staying asleep soundly across the night.
Summary
Sleep supports brain function and cognitive performance, regulates energy balance and glucose metabolism, it supports cardiovascular health, and helps to maintain a healthy immune system.
When you are depriving yourself of sleep you increase the risk of developing depression, anxiety, cardiovascular disease, infections, and impaired work productivity.
Hope the tips are useful for you.
By Doctor Zobir
References:
- Plihal W, Born J. Effects of sleep and circadian rhythm on human corticotropin releasing hormone and growth hormone secretion. Sleep. 1997 Oct;20(10):865-70.
- Cai DJ, Mednick SC, Harrison EM, Kanady JC, Mednick MA. A nap is as good as a night: the genomic signature of sleep deprivation is equally reversible by caffeine and napping. Scientific reports. 2016 Oct 19;6(1):33923.
- Haack M, Mullington JM, Holsboer F, Reichardt HM, Pollmächer T. Association of natural killer cell cytotoxicity with the cortisol awakening response and sleep. Psychosomatic Medicine. 2006 Jul-Aug;68(4):572-9.
- McEwen BS. The brain on stress: vulnerability and plasticity of the hippocampus. Metabolism. 2010 Oct;59(10 Suppl 2):S20-3.
- Pollmann S, von Cramon DY. Brain mechanisms of visuospatial working memory and their relevance for hemispatial
