Relationship between sleep disturbances and mental disorders
Sleep disturbances are present in about 90% of individuals with depression (Soehner et al., 2014) and in individuals with other mental disorders (Murru et al., 2019; Scott et al., 2021). Sleep disturbances are an important predictors of onset and relapse of major mental disorders in clinical and non-clinical population (Murru et al., 2019; Kaplan et al., 2009; Hertenstein et al., 2019; Freeman et al., 2020; Scott et al., 2021). These sleep disturbances could refer to observable changes in sleep for individuals that meet a few criteria of insomnia and/or hypersomnia but could also refer to individuals suffering from clinically diagnosed sleep disorders (Scott et al., 2021). Given that improvements in sleep was beneficial in maintaining a good mental health (Freeman et al., 2020), it could be useful to focus on improving individual sleep hygiene if an individual is experiencing any kind of sleep impairments.
What is sleep hygiene?
Sleep hygiene can be defined as a set of environmental and behavioural changes that an individual can incorporate in their daily life to maintain healthy sleeping habits (Hauri et al., 1991). It is imperative that an individual suffering with insomnia, hypersomnia, or any other sleep disorders seek out professional medical and psychological support to tackle their sleep impairments. However, individuals experiencing one or few sleep problems can usually mitigate these problem by making lifestyle changes in their sleep routines (Irish et al., 2015). Sleep hygiene awareness is important as there are growing concerns about various sleep problems as a poor-quality of sleep/less sleep often leads to impairments in an individual's cognitive skills such as attention span, concentration, motivation, problem-solving skills, decision making skills, reaction time, and overall mental health for individuals of all age-groups (Irish et al., 2015; Miyata et al., 2010; Ferrie et al., 2011; Sewell et al., 2021).
Habits to incorporate to improve your sleep hygiene
There are various sleep problems that an individual may experience, for example, problems with getting to sleep, problems staying asleep, sleeping excessively, experiencing irregular sleep throughout the night, etc (Freeman et al., 2020). Sleep hygiene strategies can help improve the overall quality of sleep (Hauri et al., 1991). While individualized strategies may be more useful in improving one specific sleep issue such as irregular sleep throughout the night (Irish et al., 2015), following are some standard recommendations are generally good recommendations to maintain a good sleep hygiene.
Short-term habit changes
Ensure that your room smells neutral or good (Kallawicha et al., 2021). Rooms with a bad odour make breathing difficult which then indirectly affects the sleep quality of all its occupants. To devoid your bedroom of any odours, it may be good practice to avoid eating in your room, to avoid smoking indoors, to avoid accumulating dirty laundry in your room for too long, washing your bedsheets and duvets often, and/or using a scented-diffuser or a scented-candle before bed.
Exposures to mold and fungi in the room contributes to numerous adverse health effects including respiratory issues and sleep problems (Kallawicha et al., 2021).
Minimize exposure to indoor and outdoor noise (Kallawicha et al., 2021). Noise pollution has been suggested to affect a number of different sleep problems such as sudden awakenings, difficulty going to sleep, difficulty staying asleep, and contributing to promote other sleep disturbances (Kallawicha et al., 2021) Within your living space, if possible, it is good to have your bedroom away from common spaces to limit excessive noise. If your living space is located in a high-noise area with high traffic, highways, near hospitals, airports, railway stations, police stations, and/or fire stations, it is good to ensure that your bedroom is insulated from all or most of the outside noise (Kallawicha et al., 2021).
It is recommended that for an optimal sleep environment, the room temperature should range between 17 degrees C to 28 degrees C with 40–60% humidity (Caddick et al., 2018). Individuals should be able to control the room temperature either by adjusting the thermostat or an air conditioner of some sort. Humidity can also be adjusted using a humidifier, if necessary.
Use black out curtains over windows and turn off all the lights to ensure that no light is entering the room (Caddick et al., 2018). Light resets our circadian rhythm, making us feel more awake. In contrast, in the dark, our brain releases melatonin which promotes sleep. It is generally recommended that individuals limit their exposure to blue light and/or another high colour light before bed (Caddick et al., 2018). Most sleep studies have suggested that exposure to no light or red light before bed often leads to various different positive sleep outcomes (Caddick et al., 2018). For individuals working night shift (that sleep during the day), blocking out light is especially recommended to maintain a steady circadian rhythm and a good quality sleep (Caddick et al., 2018). It is also suggested that for individuals that have difficulty getting up in the morning, exposure to blue light therapy can be used to either delay or advance the circadian rhythm which can help you get up earlier or later, depending on your preference (Li et al., 2022; Gooley, 2008).
Practices to Get to Sleep & to Stay Asleep
Avoid using phone or other screens before bed (Caddick et al., 2018). Screens use high colour light which is suggested to make us feel more awake (Caddick et al., 2018). Shifting your phone screen brightness to low, and setting your screen to low colour light/yellow-light may be more useful in promoting a healthy sleep hygiene.
Avoid consuming caffeine, alcohol, and nicotine especially hours before bed-time (Irish et al., 2015). Caffeine and nicotine are both stimulants which are substances used to increase focus and arousal making an individual feel temporarily alert. Depending on amount consumed during the day, the amount of caffeine and nicotine in your blood can make it extremely difficult for you to sleep. While alcohol is a depressant, making most casual user fall asleep after a certain threshold, this effect generally holds true for the first half of the night. Once alcohol is metabolized in the body, quality of sleep during the later part of the night is often poor (Irish et al., 2015).
Reduce acute stress to promote a better quality of sleep (Irish et al., 2015). Stress is generally associated with a higher physiological arousal which means that you are likely to be more alert, and so naturally, less likely to sleep. The problem is worsened, if there is an exposure to stress close to bedtime as not only would you have difficulty falling sleep, but it is also likely that you may wake throughout the night due to random bursts of arousal, and overall experience a low-quality sleep (Irish et al., 2015). While it is almost impossible to get through life without being exposed to some sort of stressors, incorporating stress-management techniques in your routine may be useful if you experience acute stress often or if you generally find coping with stress difficult. There are a range of relaxation and mindfulness-based stress-reduction techniques that you can use to reduce daily stress (Irish et al., 2015; Call et al., 2014). For example, sitting meditations, hatha yoga, and body scans have found to be useful in decreasing stress and anxiety levels (Call et al., 2014).
If possible, avoid night shifts all together as night-shift work in the short-term can disrupt an individual's circadian rhythm and in the long-term lead to a range other physiological and mental health issues (Ko, 2013; Dai et al., 2019; Wang et al., 2015).
It would be good to avoid alternating between night and day shifts too often (Rajaratnam & Arendt, 2001). It is good to create clockwise rotations rosters 3 day shifts, 3 evening shifts, 3 night shifts, and 3 recuperative days off. It is suggusted that the individual should get the 3 days off after their night shift so that they can reset their circadian rhythmn which is necessary for optimal sleep, performance, physical and mental health (Burgess, 2007; Rajaratname & Arendt, 2001).
It is impossible to work in healthcare and not have to do a nightshift every so often, in which case it is good to go into the nightshift with a game plan that would prioritise your health and your work-performance. McKenna and Wilkes (2018) recommend that on the first day of your night shift, it would be useful to allow yourself uninterrupted amount of sleep the morning of your shift- which means waking up without an alarm. Further, it would be good to nap during the day to reduce the amount of sleep debt. Our body naturally experiences a circadian dip between 2pm and 6pm, so, napping during these hours would be beneficial. If napping during the night, in your breaks, it is best to keep your nap shorter than 30 minutes as that would ensure that you are not falling into the deep sleep stage as waking up during this stage would exhaust you, inevitably affecting your performance. Towards the end of your shift, avoid consuming caffeine as you want to be able to fall asleep as quickly as you can once you reach home. It is also advisable that you don't drive back yourself after your night shift. When trying to reset your days after a few nightshifts, it is best to take a 90–180-minute nap which is equivalent to 2 circadian sleep cycles and then try to adjust to your daily day time routine to avoid any sleep debt. It could be good to go out in the sun, socialize, and try to go to bed at a reasonable time.
With travelling across countries, continents, and time zones, it is natural to experience jetlag. Some short-term symptoms to jetlag include, daytime tiredness, difficulty in trying to get to sleep (especially after flying east), early morning wakening (after flying to the west), overall disrupted night sleep, impaired day time alertness and performances, gastrointestinal issues, loss of appetite, etc (Rajaratnam & Arendt, 2001). While experiencing jetlag in the short-term may only affect our performance and well-being a little, it has been suggested that in the long-term experiencing such circadian disruptions can result in physiological and cognitive deficits (e.g., deficits in memory and slow reaction time).
Given the range of issues that comes with poor quality of sleep, it is important to maintain a good sleep hygiene and to accelerate circadian adaptation (Rajaratnam & Arendt, 2001). Exposure to bright light in the mornings may be useful to make waking up easy, while avoiding light at night would making it easier to fall asleep. Taking the hormone melatonin pills may be able to manipulate your circadian rhythm. Travelling from west to east may be easier as it is likely that the time you land would be evening/night so you can easily sleep with your circadian rhythm adapting itself to the new local time on the first night.
If the time zone shift is only for a day or two, it would not be worth trying to manipulate your circadian rhythm as you will need to adapt back upon your return. In that instance, it is recommended that you try and maintain alertness and performance (Rajaratnam & Arendt, 2001) maybe by ingesting coffee (with a high caffeine concentration).
Long-term habit changes
If you are suffering from persistent long-term sleep problem or with various different sleep problems, you may need to seek profession medical and/ or psychological support. For example, there are imagery rehearsal therapy for nightmare-related issues, other Cognitive Behavioural Approaches, psychological therapies for insomnia and hypersomnia, medicinal approaches for various sleep disorders, and others. Reaching out to your General Practitioner may be a good first-step here.
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