“To die, to sleep – to sleep, perchance to dream – ay, there’s the rub, for in this sleep of death what dreams may come…” Hamlet Act III Scene I
Introduction
Sleep is probably the most overlooked health habit. The modern world has a major issue with sleep deprivation. In any natural environment, animals rarely become sleep-deprived. Our bodies are naturally adapted to the rhythm of the sun; science is still only just understanding these interactions.
Poor sleep is associated with major health issues, including:
- Cardiovascular disease
- Dementia
- Depression
- Anxiety
- Forgetfulness
- Testosterone deficiency
- Metabolic syndrome
- High blood pressure
- Obesity
- Poor workout recovery
When does sleep begin?
Sleep generally begins when the sun goes down and the temperature begins to drop.
Throughout the course of the day, there is an accumulation of a chemical called adenosine in our brains. As the sun sets and the day cools, the adenosine concentration and other signals induce the release of melatonin, a sleep hormone, in our brains.
Other chemicals then come into play and our brain enters sleep mode.
What happens to our bodies as we sleep?
During sleep mode, our alertness centres shut down and we start to dream. Our metabolic rate lowers. Our brain cells start to repair, regenerate and lay down long term memories. Body temperatures will go down, our breathing changes, our kidneys keep more water and concentrate our urine.
A lot happens!
Also, overnight, we prepare to release hormones. Growth hormone and testosterone are both released most at the end of sleep, around about 5am for most people. Hence the phenomenon of morning glory or an early morning erection. This is also the time of the day with the most heart attacks; draw your own conclusions!
There are many factors that lead to us falling asleep; these include all the settings that help release melatonin and ease the brain into sleep. Factors such as light and noise exposure, stimulation and stress all play a role in sleep.
Does everybody go to sleep in the same way?
Some people have genetic differences with the processing of adenosine, melatonin and other sleep cadence hormones that change how easily they sleep.
Many people will also have lifestyle and health habits which will impact with the sleep cadence. For example, some people may drink more caffeine, have higher stress and have other reasons to be more alert. All of these impact adenosine, melatonin and thus sleep. We know that caffeine, watching TV or playing games etc. all make it harder to sleep well.
There is a small percentage of people who function on a delayed sleep cycle. This is where the accumulation of adenosine and release of melatonin is set back by a few hours. Often these people tend to sleep late and wake up late; much to the annoyance of their parents, teachers and work colleagues!
Finally, some people just prefer to stay up light staring at a screen. Bright lights and stimulation all impede the adenosine and melatonin release. Without the right light and environmental settings, sleep is harder, delayed and less deep.
What is melatonin?
Melatonin is a hormone released by a gland in the brain and is generally associated with sleep. It is more than just a sedative hormone; it is a key metabolic hormone.
Melatonin does not act alone; it has a lot to do with a daytime hormone called cortisol.
Cortisol, a ‘fight or flight’ hormone, is released by our adrenal glands early in the morning. It is a stress hormone and gives us our ‘get up and go’. During the day, it is further released if there is stress or hunger.
If there are issues with sleep, the cortisol system is disrupted and this can cause morning fog or tiredness.
In a way, melatonin exists in a ‘dance’ with cortisol. In the morning, cortisol rises and gives us a boost whilst at night, cortisol falls and melatonin relaxes us. Melatonin helps counteract cortisol during the night and enable sleep. By doing so, it also lowers insulin and other inflammatory molecules.
Melatonin and Cortisol exist in a tight and exacting balance. When we do not get good sleep, we do not get enough melatonin and we end up with a cortisol predominant picture. This can feel like being constantly tired, run down, gaining weight, poor metabolism; what is commonly called ‘adrenal burnout’.
What happens to our fat burning during sleep?
Sleep varies in every person. As we sleep, we enter a fasting or starvation state and our body burns our fat stores to provide energy. Our mitochondria, the important batteries of our cells, enter a vital and healthy starvation mode and begin to clean up cellular and DNA damage which is vital for health.
Similarly, across the body all tissues will be repairing and regenerating both their cells and their hormones. Growth hormone and thyroid are made by the body at night.
In short, sleep helps us live longer and cleaner as we are able to repair our body overnight and make helpful hormones.
What happens to our brain during sleep?
The brain is one of the biggest consumers of energy in the body. It requires substantial energy and repair time to function well.
Brain cells are very vulnerable to toxins. Toxins are always occurring in the body as the waste products of normal cell activity. Toxins also build up from our environment (E.g alcohol, carbon monoxide from cars) and hit the brain during the day.
Night time is when the brain is able to focus on cleaning up toxins.
Night time is also when the brain is best able to repair itself. This is because the body is able to divert a lot of resources to the brain away from other body functions like digestion, muscles etc.
As we sleep, a chemical called Brain Derived Neurotrophic Factor (BDNF) is released. BDNF helps the brain grow neurons, form memories and is protective against depression.
BDNF and melatonin are both protective of the brain and enhance mood and mental sharpness. They are both enhanced by factors such as voluntary exercise, caloric restriction, intellectual stimulation, and various treatments for depression such as antidepressants
What factors can interrupt good sleep?
The commonest impediment to good sleep is our routine. With the advent of web connectivity, most people are prone to work until late at night, watch a screen, scroll or consume content online and miss the organic cues for bed such as temperature, sunlight and physical fatigue.
The cadence of the day is also interrupted by a disrupted meal habit, young children, ambient traffic noise, shift work, socialising or travel.
Chemical interruptions to good sleep are also common. Caffeine and alcohol both block adenosine. Sugar ingestion late at night can disrupt sleep. Heavy digestion late in the evening has a similar effect. Even the dosing of some herbs and natural medicines may have an adverse impact. For example, the body releases the equivalent of about 0.3mg of melatonin per night. Meanwhile, melatonin supplements generally start at 3mg and this can give a disrupted, ‘hangover’ like sleep to some people.
Blue light is a prominent signal to our brain not to sleep. It portends predators as well as the desire to wake up and hunt food. Humans have been around 300 000 years; blue light, a mere 50. Blue light can come from screens or simply being awake too late at night.
How can poor sleep affect our health?
Poor sleep is associated with…
- Depression
- Headaches
- Low hormones (testosterone, thyroid)
- Obesity
- Metabolic stress
- Cognitive Decline
- Frontal Headaches
- Blurry vision
- Forgetfulness
Sleep deprivation is a well established cause of depression, poor memory, interrupted hormones, inflammation and disease. Sleep is not optional; it is when our body needs to repair and replenish. In fact, sleep medicine is now a distinct medical specialty; often attached to respiratory medicine.
What medical conditions can impact sleep?
Obstructive sleep apnoea is an illness where somebody cannot get enough air flow into their lungs when they are asleep. It is usually caused by an obstruction to the airflow passage in the throat that is made worse when the person is on their back asleep. This is typically a large tongue, narrower space at the back of the throat or a fatty or crowded neck.
Sufferers are often described as ‘choking’ to a halt in their sleep; a loud snoring or gagging sound followed by a lack of breathing. This is because the airways are not open enough to let air into the lungs. During the day time, we are upright and walking and can use our alertness to keep the airways open but during sleep, we rely on the natural tone and anatomy of the throat to keep air flowing.
Sleep studies are tests that monitor oxygen and sleep activity overnight. If somebody has this test and it shows that they literally stop breathing overnight, then they have sleep apnoea. Apnoea means ‘no breathing’.
Every time a person loses oxygen, they come out of deep sleep. People with obstructive sleep apnoea are typically very tired during the day.
Obstructive sleep apnoea is a major cause of disease including obesity, diabetes, high blood pressure and the cardiovascular events that follow this. This highlights how important sleep is to keep our body functioning; without good oxygen delivery and good sleep state in the brain, our body declines in many ways.
Finally, not everybody with an airways blockage or obstruction gets full blown obstructive sleep apnoea. Snoring is often a subtle version of poor quality sleep. Snoring in a young person should always be referred to a doctor. Anybody without good air flow into their lungs at night time should be evaluated by a doctor.
What are the factors behind good sleep?
- Cool Room
- Limiting caffeine to before lunch
- Exercise
- Minimise Blue light at night time
- Keep regular hours, sleep with the sun
- Eat well, far from bed time
- Low dose melatonin
- Early morning waking and sun exposure
Natural treatments and supplements for good sleep
Morning
- 5HTP (a serotonin or healthy brain hormone precursor)
- Ashwagandha (an adrenal gland supplement)
Nighttime
- L- theanine or green tea extract (enhances a relaxing brain chemical called GABA)
- Melatonin liquid (<1mg)
- Chamomile or lavender aromatherapy
- Magnesium (as a powder or a tablet)
- CBD (in jurisdictions where this is legal)
Other interventions
- Exercise
- Turn off TV and put the phone away after dinner
- White noise therapy
- Blackout curtains
- Wake up early to gain sunrise light
- Minimise caffeine after 1 pm
