Sleep is as essential to our daily needs like food and water. Although we may feel that sleep simply rests our tired bodies, our brain remains active throughout the night. Sleep plays a critical role in the brain as well as physical functioning.
Our internal body clock, called a ‘Circadian clock’, tells us when we are ready to sleep. There are several circadian clocks in the body, found in the brain and other organs. They are triggered by cues such as daylight (we feel alert) and darkness (we feel drowsy). These clocks can also be triggered by artificial bright light or stimulants like caffeine and alcohol that cause us to feel awake even if it is night-time.
There are several phases of sleep our body experiences. They are classified as REM (rapid eye movement) and non-REM sleep. We cycle repeatedly through these phases about 4-6 times throughout the night, and it is not uncommon to wake up briefly between cycles.
Melatonin is a hormone released by the brain when it is dark. It travels to cells to tell the body to sleep. Sunlight or exposure to light inhibits the production of melatonin and increases the release of cortisol, which awakens us. If we are exposed to too much artificial light (such as the blue light emitted from smartphones or televisions) late at night, less melatonin may be released making it harder to fall asleep.
Serotonin, the body’s “feel-good” chemical, is a neurotransmitter associated with both sleep and being awake. The brain releases this chemical during daylight but also uses it to form melatonin at night.
Sleep helps to process your thoughts from the day as well as store memories, so a lack of good-quality sleep can lead to difficulty focusing and thinking clearly. You may feel tired, irritable, or anxious during the day. Performance at work or school may suffer. Your reaction time may be slowed, increasing the risk of driving accidents.
In children, insufficient sleep can lead to attention and behaviour problems or hyperactivity. In the elderly, lack of sleep may decrease focus and attention, leading to a greater risk of falls, bone fractures, and car accidents.
There are several reasons people may get insufficient sleep:
⦁ Poor sleep habits (watching television or using screens late at night, drinking caffeinated or alcoholic beverages at night, not following a regular sleep schedule).
⦁ The sleep environment is too noisy, too light, or otherwise not conducive to sleep.
⦁ You attempt to sleep outside of the body’s natural circadian clock (working an overnight shift and trying to make up for sleep during the day).
⦁ Sleep disorder, such as sleep apnea, insomnia, or periodic limb movements reduces deep or REM sleep or causes frequent awakenings.
⦁ Medical condition such as heart, lung, or kidney disease, or chronic pain, causes frequent awakenings.
⦁ Amongst the several reasons listed above, sleeping in a noisy environment is considered to have a high risk to the health and well-being of humans.
Environmental noise, especially that caused by transportation means, is viewed as a significant cause of sleep disturbances..
The European Union has reported that people exposed to night noise levels above 40dB on average throughout the year can suffer sleep disturbance, while long-term average exposure above 55dB can trigger elevated blood pressure and lead to ischaemic heart disease. Environmental noise causes approximately 16,600 cases of premature death in Europe each year, with almost 32 million adults estimated to suffer annoyance and over 13 million adults estimated to suffer sleep disturbance.
In the UK, a study estimated that 54% of the population was exposed to noise pollution above recommended levels of 55 decibels. Exposure to air traffic noise has also been linked to a negative impact on student performance in educational institutions, recording a significant relationship to poor reading and mathematical performance.
Apart from these measurable effects and the subjective feeling of disturbed sleep, people who struggle with nocturnal environmental noise often also suffer the next day from daytime sleepiness and tiredness, annoyance, mood changes as well as decreased well-being and cognitive performance. But there is also emerging evidence that these short-term effects of environmental noise, particularly when the exposure is nocturnal, may be followed by long-term adverse cardiometabolic outcomes.
Nocturnal environmental noise may be the most worrying form of noise pollution in terms of its health consequences because of its synergistic direct and indirect (through sleep disturbances acting as a mediator) influence on biological systems. Duration and quality of sleep should thus be regarded as risk factors or markers significantly influenced by the environment.
We spend 90% of our time indoors and this percentage has increased more so in the last few years due to COVID 19. There are various technologies available to minimise noise transfer. Acoustic proof windows and doors, along with curtains and carpets cut down noise transfer but also encourage people to spend more time indoors.
The trees and plants have a natural ability to cut down dust and noise pollution. However, most urban spaces cannot afford to maximise greenery due to high value of real estate. There is a growing awareness amongst urbanites who would like to live away from the hustle and bustle of urban spaces and live close to nature. These urbanites choose to wake up to the birds chirping and sleep to the lullaby of crickets.
When we are in tune with nature, we tend to be healthy in mind, body and soul.