Sleep Cycles
Pro Health Care
Multidisciplinary clinics in Adelaide - focused on providing the highest level of patient care for over 35 years.
The average Australian adult should get between 7-9 hours of sleep every night. Babies and young children need much more sleep than the average adult.
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Sleep is essential for restoring mental and physical health as it refreshes the mind and repairs the body. Minimal sleep or sleep deprivation can cause fatigue, lack of concentration, mood swings, impaired judgment and reaction time and poor memory.
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Circadian Rhythm and Melatonin
Circadian rhythm is the process of regulating the sleep-wake cycle and repeats roughly every 24 hours. Different systems in the body follow the circadian rhythm, synchronised by a function in the brain, sometimes referred to as the circadian pacemaker. The circadian pacemaker is located in the superchiasmatic nucleus (SCN), which is found in part of the brain called the hypothalamus. The SCN is highly sensitive to light, which acts as a cue that influences the internal clocks within the body. Hence, why the circadian rhythm is linked to the cycle of day and night.
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Melatonin is a hormone produced by the pineal gland in the brain, and controls the sleep-wake cycle. When it is dark, the body produces more melatonin to start the sleep process, and when it begins to get light, the production of melatonin is restricted.
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When the circadian rhythm is in sync, it can result in consistent and restorative sleep, however when it is out of sync, it can lead to significant sleep problems such as insomnia. It can also result in an individual having trouble falling and staying asleep, and constant waking up throughout the night. It can also mean the quality and amount of sleep they are getting is much less.
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What can Disrupt Circadian Rhythm?
Changes to circadian rhythm can occur over the short or long term. A common reason for the circadian rhythm to be disrupted is jetlag. Jetlag occurs when an individual crosses multiple time zones in a short amount of time.
Shift workers also often experienced interrupted circadian rhythms due to having to work through the night and sleep during the day. The same can be said for truck drivers, they often have deadlines to meet and have to drive long periods without rest. This can make someone’s sleep schedule the complete opposite of what it’s meant to be.
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Sleep Stages
There are four sleep stages. There is one rapid eye movement (REM) sleep stage, and three non-REM (NREM) sleep stages. These stages are determined based on brain activity during sleep. Throughout the night the total amount of sleep is made up of several rounds of the sleep cycle. The average person will experience between four-six sleep cycles a night.
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Stage 1 / N1
This is the ‘dozing off’ stage, normally lasting between 1-5 minutes. The body is in the process of relaxing and brain activity begins to slow. Hypnic jerks, or twitches are common in N1, as the body is transitioning from being awake to being asleep. It is easy to wake someone during this stage, however if the person isn’t woken they can quickly move from stage 1 into stage 2. A person generally doesn’t enter back into stage 1 throughout the different sleep cycles.
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Stage 2 / N2
During N2, there are some physical changes within the body. Including a decrease in body temperature, relaxed muscles, breathing is slowed and heart rate decreases. Brain waves begin to slow and show a new pattern, along with eye movement stopping.
N2 initially lasts for 10-25 minutes, however it becomes longer during each new cycle. Overall, a person will spend about half of their sleep in N2.
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Stage 3 / N3
Stage 3 is known as deep sleep and is the hardest stage to wake someone up in. N3 sees the body relax and slow down even further from N2. N3 is the most crucial to restorative sleep, and is the most essential for feeling rested and staying healthy.
Majority of time spent in deep sleep is in the first half of the night. In the first few sleep cycles N3 lasts between 20-40 minutes, but as the night progresses N3 get shorter, and more time is spent in REM sleep.
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Stage 4 / REM
During REM sleep brain activity increases to a level similar to that of when you’re awake. However, your body become temporarily paralysed, aside from the muscles that control breathing and the eyes which move quickly. REM sleep is crucial for cognitive functions such as memory and learning.
During REM sleep is where vivid dreams happen due to the increase in brain activity. Dreams can happen in all of the stages, but are more intense in REM.
REM sleep happens after 90 minutes. As the sleep cycles go on, REM sleep increases in length, especially in the second half of the night.
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How to have a Healthier Sleep Cycle
Having a good routine before bed time can help in having a healthier sleep cycle. Some things to do in the lead up to bed time is:
·????????Go to bed and wake up at the same time each day where possible
·????????Limit screen time before bed- try to switch devices off 1 hour before bed time
·????????Avoid caffeine 4-6 hours before bed
·????????Sleep environment- ensure room temperature isn’t too hot or cold
·????????Limit day time naps to no more than one hour, and avoid napping late in the day
·????????Regular physical activity can promote better sleep
·????????Write your worries down on a piece of paper before bed and revisit them tomorrow
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About Pro Health Care
Our ethos and core values have stemmed from the work of three prominent General Practitioners working within the Western Suburbs of Adelaide from which Pro Health Care was founded in 2007. The commitment, time and care they gave their patients over 35 years is the cornerstone of our philosophy.
Since then, our medical centres have been structured around our patients as we emphasise a holistic approach to managing health and well-being through doctor’s services and multi-disciplinary care — whether it be general medical, physiotherapy, podiatry or anything in between. The medical framework through which we operate focuses on collaborative reasoning and communication, a combination of values which we believe is the path to achieving the highest possible standards of care for our patients. Visit our website?here.