Sleep Quality vs Quantity
HOLISTIC HEALTH SERIES: SLEEP
Sleep is arguably one of the most important factors to consider in an individuals overall health journey. Sleep can help us heal, deal with stress, consolidate memories and learning, and improve recovery. Sufficient sleep sets us up for everything else to function that bit better. In 2019-20 it was estimated that 1.9 million Australians suffered from some kind of sleep disorder.
How much is enough? Quality vs Quantity
According the Sleep Foundation, a healthy adult needs 7-9 hours sleep per night. Teenagers, children and babies need more again to enable growth and development. However, a good night’s sleep is not just measured in hours but also in quality. When we sleep we go through REM (rapid eye movement) sleep and NREM (non-rapid eye movement) sleep. We need our body to go through cycles of REM and NREM sleep for a quality night’s sleep. Each sleep cycle typically lasts 90-120 minutes and a typical night’s sleep involves four to five cycles.
The stages of sleep
NREM stage N1:
The transition from wakefulness to sleep. Your eyes are closed but you are easy to wake. Heartrate and breathing begin to slow down, muscles begin to relax.
NREM stage N2:
Compromises the largest percentage of sleep time. Body is preparing to enter deep sleep. Heart rate and breathing continue to slow, body temperature drops, no eye movement.
NREM stage N3:
Known as slow wave sleep, this is the deepest stage of sleep. Arousal from sleep is difficult, heartrate and breathing are at their slowest, the body is fully relaxed and no eye movement is present. During this deep stage of sleep delta waves are present in the brain, tissue repair and growth and cell regeneration occurs, the immune system is strengthening.
REM sleep has two phases; phasic and tonic. Phasic REM sleep contains bursts of rapid eye movement, tonic does not. REM sleep occurs about 90 minutes after falling asleep, the first REM stage will last around 10 minutes, increasing with every sleep cycles, with the last being anywhere between 30-60 minutes. During this stage; eye movements become rapid, breathing and heart rate increase, muscles become paralysed but twitches may occur, brain activity is increased. REM sleep is primary dreaming stage of sleep.
When people suffer from sleep disturbances, the stage of sleep most commonly lacking is deep NREM sleep. This is our prime time for recovery and all the important functions that sleep provides.
Sleep dysfunction can be linked to a multitude of health conditions, increased stress, diminished concentration and productivity levels and as we’ve all felt – low energy levels.
Caffeine and sleep:
Before we understand how caffeine can affect sleep, we need to understand the role of adenosine. Adenosine is a molecule that when it binds with A1 receptors in the brain, promotes sleepiness and muscle relaxation. Adenosine can be produced by physical activity and intensive brain use, so if we have a big day of manual or mental labour, adenosine builds up throughout the day.
When we wake up in the morning our body has ideally metabolised all the adenosine molecules over night.
This is when most of us will have our first cup of coffee.
Caffeine levels peak within the bloodstream within about two hours of consumption. At this point the caffeine is now competing with and preventing the adenosine from binding with those A1 receptors in the brain (the receptors that allow for the tired feeling). This is how coffee works to keep us awake and alert throughout the day.
After a few hours the caffeine begins to unbind from the A1 receptors and is metabolised by the body.
You may have heard of caffeine ‘half life’. The half life is the amount of time it takes for the concentration of the substance to be halved. For caffeine this can be anywhere from 3-10 hours depending on the individual and the amount consumed. The remainding caffeine can stay in your body for a while longer.
By the time majority of the caffeine has been metabolised, the adenosine molecules will start to bind to the A1 receptors in the brain and bring on that tired feeling we all know so well.
When we finally go to sleep our body will start recovering and metabolising all the adenosine molecules produced throughout the day.
This is why sleep is so important as if we do not get adequate sleep to aid this process, we can wake up before this process has finished, with adenosine molecules still in our brain, leaving us feeling groggy and under-rested.
Circadian Rhythms and the Sleep Wake Cycle
Circadian rhythms are 24 hour cycles that are a part of the body’s internal clock. We see circadian rhythms all through nature, they are what’s responsible for flowers opening and closing with the light and for nocturnal animals in rest during the day time.
For us circadian rhythms coordinate mental and physical systems; most notably the sleep-wake cycle.
Other times you may notice circadian rhythms at play is through the digestive system producing proteins at typical meal times, making you hungry or crave a meal.
If your circadian rhythm is unregulated or ‘off’, the body’s systems do not function optimally. A disturbed sleep-wake cycle can facilitate sleep problems; trouble falling asleep, waking during the night and not being able to stay asleep/wake up in the morning, all resulting in a lower quality or disrupted sleep.
Tricks to maintain a healthy circadian rhythm
Sunlight: Natural light is the strongest physiological cue there is for the sleep wake cycle. Exposing yourself to natural light in the first hour of waking and as the sun is setting will help to trigger physiological responses to regulate waking and falling asleep.
Consistency: Maintaining a consistent waking time and bed time allows your circadian rhythm to regulate. This is hindered if waking times are dramatically differed day by day. Unfortunately this means that those big sleep ins on the weekend might be having a negative effect.
Exercise: Daily exercise is beneficial to regulating your circadian rhythm. Movement in the morning helps achieve wakefulness.
Temperature: Your body goes through a 24 temperature cycle, reaching its coolest temperature overnight and warming throughout the day. Having a cold room to sleep in allows your body temperature to drop to facilitate this rhythm.
Why do I feel tired after a massage?
A massage stimulates the parasympathetic nervous system, also known as the rest and digest system.
Different to the sympathetic nervous system, which is more commonly known as the fight or flight system, which has a lot to do with adrenal responses to external stimulants and stressors. The sympathetic nervous system engages autonomic and involuntary responses such as increased heart rate, increased respiratory rate, sweating or increased awareness (think stress response).
The parasympathetic nervous system is most at play in relaxed states, it works to slow down certain responses and bring a state of calm to the body to encourage rest, relax and repair. The parasympathetic nervous system works to bring the body to a homeostatic state and maintain long term health. These responses include an increase in digestive function, decreased heart rate and relaxed muscles, encouraging digestion and sleep.
If you’ve ever felt like you’re in a ‘food coma’ after a big meal, this is why. Eating stimulates your parasympathetic system. Have you ever had your stomach gurgling towards the end of a massage? Same reason.
The activation of the parasympathetic nervous system through massage shows how massage can play a beneficial role not only in the maintenance of soft tissue injuries but in your overall health. Massage can increase relaxation helping those suffering from stress or sleep issues.
Tips to improving sleep:
- Limit screen time before bed. Try to turn off all electronics an hour before wanting to go to sleep.
- Use sunlight to set your circadian clock. By viewing sunlight within 30 minutes of waking and as the sun is setting in the afternoon, you are helping to set your circadian clock
- Restrict caffeine intake from 8 hours before you intend to go to sleep.
- Consider the temperature in your bedroom – your body needs to drop 2 degrees to fall asleep. Try having your room cool with blankets that you can remove or stick a foot out from under.