Motivation and emotion/Book/2024/Sleep onset optimisation

Sleep onset optimisation :
What techniques assist in falling asleep promptly?

Overview

Scenario

It is 1:00 AM, and the day has finally come to an end. You are mentally and physically exhausted, as you hop into bed, you put your head down on the pillow, pull your duck feather duvet to your chin, roll onto your side, and reach for your phone. The only energy you have is to doom scroll on Instagram and see what the rest of the world did today. Half an hour goes by, you set your alarm for 06:30 AM and put your phone down for the night. You find your brain is now racing, thinking about all the tasks you need to complete for tomorrow, you are thinking about several conversations you had today and if you offended anyone. You look at the time … 01:00AM?! Now you are stressing with a racing heart and brain pumping with anxious thoughts, about trying to fall asleep quickly and calculating how much sleep you can get from now until your alarm goes off.

Figure 1. Example of how sleep deprivation affects daily activities

Sleep deficiency heavily affects the body mentally and physically (see figure 1). Lack of sleep can impair the body to execute daily activities eg. work, school, raising a family and social interactions due to feeling tired, low energy and low mood. Therefore affecting a person's motivation and emotional regulation causing mental health issues such as depression, anxiety and stress{[g}}. Through psychological science, sleep onset optimisation developed into [grammar?] way to promote techniques tailored to [grammar?] person who is struggling with poor sleep hygiene.

Focus questions:

What is sleep?
What is sleep onset optimisation?
Is there a relationship between motivation and sleep?
Is there a relationship between emotion and sleep?
What techniques help us fall asleep promptly?

Sleep onset optimisation

Sleep onset is the transition from a state of wakefulness to sleep. Humans need sleep so the body and mind can rest, recover, and restore energy for the next day. When an adult has 6-8 hours of completed cycles of NREM and REM they have more energy to learn new tasks, skills, and knowledge, work towards personal and occupational goals, exercise, deal with stress, and socialise (Vyazovskiy, 2015). Sleep onset optimisation is important as it impacts every aspect of the brain (Mu & Huang, 2019) and is the foundation for cognitive control, emotional regulation, and motivation (Mu & Huang, 2019), (Vandekerckhove & Wang, 2017). Poor sleep can easily occur due to a range of factors including changes in the environment, detachment from parents, social media use, social interests, and work.

What is sleep?

Sleep can look different for every human however the generic definition is a period of time at night when the brain signals the body to lie down and close eyes caused by the circadian clock (Colten & Altevogt, 2015). The role of the circadian clock (see Figure 1), is to pick up different light cues in the environment throughout twenty-four hours and this is achieved by the suprachiasmatic nucleus (SCN) which is located in the hypothalamus (Colten & Altevogt, 2015). The big communicator between the wake and sleep transition is the brain stem sends signals to the muscles to relax which is important so we do not physically act our dreams (Colten & Altevogt, 2015). The thalamus is key within sleep because it constantly processing information from short to long-term memory (Colten & Altevogt, 2015). However in sleep becomes quiet by allowing the brain to tune out to the external world which is important so the brain can receive a deep sleep (Colten & Altevogt, 2015). The pineal gland (PG) sends melatonin after the PG has received signals from the SCN which helps us to sleep in the dark (Colten & Altevogt, 2015). The average adult needs 6-8 hours of sleep, compared to teenagers (12-18) who need up to 12 hours, and babies who require up to 15 hours of sleep due to the energy exerted while their body is developing physically and mentally (Colten & Altevogt, 2015).

Figure 1. Circadian rhythm

Healthy sleep is presented in a 70-120 minute cycle of non-rapid eye movement (NREM) which includes four stages of sleep (N1, N2, N3, N4) and rapid eye movement (REM) (Carskadon& Dement, 2011), (Colten & Altevogt, 2015). The first stage of sleep is N1 with a duration between 1-7 minutes (Colten & Altevogt, 2015). The body prepares for sleep by slowing down heart rate, breathing, brain waves, and eye movements, and also the stage where muscles relax and random twitches occur (Carskadon & Dement, 2011), (Colten & Altevogt, 2015), (Robinson, 2022). The second stage of sleep is N2 with a duration between 10-25 minutes (Colten & Altevogt, 2015). N2 is where memory consolidation occurs (Colten & Altevogt, 2015) activated by processes in the neocortex, thalamus, and hippocampus (Kosuke Kaida et al., 2023). The third stage of sleep is N3, with a duration of 20-40 minutes (Colten & Altevogt, 2015) where the body repairs muscles, tissues, and bones (Robinson, 2022). REM is the fourth and most critical stage of sleep and occurs after being asleep for 90 minutes (Colten & Altevogt, 2015), (Robinson, 2022). REM is responsible for dreaming which is essential for a person’s motivation and emotional regulation therefore introducing the importance of sleep.

Sleep onset optimisation; importance on motivation and emotion

[Provide more detail]

The importance of sleep

Sleep onset is the transition from a state of wakefulness to sleep. Humans need sleep so the body and mind can rest, recover, and restore energy for the next day. When an adult has 6-8 hours of completed cycles of NREM and REM they have more energy to learn new tasks, skills, and knowledge, work towards personal and occupational goals, exercise, deal with stress, and socialise (Vyazovskiy, 2015). Sleep is important as it impacts every aspect of the brain (Mu & Huang, 2019) and is the foundation for cognitive control, emotional regulation, and motivation (Mu & Huang, 2019), (Vandekerckhove & Wang, 2017). Poor sleep can easily occur due to a range of factors including changes in the environment, detachment from parents, social media use, social interests, and work (see figure 2, table 1).

Table 1.

Sleep vs Motivation and Emotion


	Poor sleep	Good sleep
Motivation	Decreases	Increases
Emotional regulation	Decreases	Increases

What is the relationship between sleep and motivation?

Motivation is the energy and effort of behaviour to cause movement and performance (Massar et al., 2019). Motivation determines rewards, values, decision-making, learning, goals, and cognitive control within a person (Kim, 2013) through processing, generating, regulating, and maintaining motivation (Kim, 2013). The regions of the brain responsible for daily motivation include the ventral striatum, orbitofrontal cortex, anterior cingulate cortex, dorsolateral prefrontal cortex (Kim, 2013), and nucleus accumbens (Liu et al., 2016). Basic motivation is demonstrated physiologically through survival mechanisms of hunger, thirst, sleep, breath, and sex by homeostatic and circadian cycles. (Axelsson et al., 2019). Physiological needs must be satisfied before a person performs advanced daily motivation within the workplace, university, family, and social engagements. For example, sleep is a basic need and critical for motivation by restoring energy, attention, and cognitive control in NREM and REM (Axelsson et al., 2019) (Horne, 1993). Therefore sleep is important because it helps the person learn, perform goals, gain rewards, and stay consistent with personal values and decision-making (Kim, 2013). The dorsolateral prefrontal cortex impacts motivation specifically in wakefulness for example in planning, working memory, sensory comparisons, decisions for action, attention, and goal-directed behaviour (Horne, 1993). Zooming out from the DLPC, the prefrontal cortex (PFC), anterior cingulate cortex (ACC), and ventrolateral PFC (VLPFC) work together for central executive function and working memory (Dai et al., 2020), (Horne, 1993). Working memory is essential for motivation by distinguishing between the cost and reward of effort and energy used towards specific tasks presented throughout the day (Grogan et al., 2022). Sleep deprivation causes working memory to decline due to a change in neural activation highlighted in the PFC (Frenda & Fenn, 2016).

How does self efficacy theory correlate with sleep onset?

Sleep onset optimisation and the self-efficacy theory are positively correlated because good quality sleep helps a person to have energy and the capacity to build positive internal beliefs about achievement and goals (Ghose et al., 2022). The quality of sleep can determine how a person behaves due to their motivation throughout the day (Ghose et al., 2022). For example, when a person is trying to quit smoking and sleep deprivation is experienced, self-efficacy about believing they can quit smoking is decreased (Araújo et al., 2019), (Ghose et al., 2022). The self-efficacy theory and quality of sleep can determine the motivation behind the level of self-care demonstrated in behaviour (Schutte & Malouff, 2015). For example, the motivation to exercise, take medication, eat healthily, and go to medical appointments is displayed when sleep onset optimisation has occurred (Ghose et al., 2022) (Schutte & Malouff, 2015). Research has shown that low self-efficacy is a predictor of insomnia (Ghose et al., 2022), (Schutte & Malouff, 2015). Insomnia is a sleeping disorder that causes poor sleep/sleep deprivation due to staying in a state of wakefulness at bedtime (Roth, 2007). The self-efficacy theory suggests that people who believe they can improve sleep habits and more motivated to tackle insomnia's root causes rather than turning to medication (Ghose et al., 2022). The physiological experiences of insomnia cause a state of alertness due to arousal of the sympathetic nervous system which increases heart rate, cortisol, and insulin resistance while decreasing the immune system (Alhola & Polo-Kantola, 2007). However further studies need to be conducted to predict treatments to enhance positive self-efficacy beliefs to reduce stress and anxiety about sleep (Ghose et al., 2022). Therefore techniques to assist sleep onset optimisation need to be exerted to reduce sleep deprivation and sleep disorders to improve mood, and cognitive performance, memory consolidation, as shown in daily behaviour and motivation (Alhola & Polo-Kantola, 2007), (Ghose et al., 2022), (Roth, 2007).

What is the relationship between sleep and emotion?

Figure 3. Sleep and emotions

Emotions are the mind and body's integrated response to a stimulus which determine how a person thinks and feels in response to an event (Izard, 2019). Emotions help a person adapt to their environment through physiological arousal, expressive behaviours, and conscious experience (Izard, 2019). The feelings of happiness, sadness, anger, disgust, joy, interest, and fear are integrated through distinct neural activity in the brain stem, amygdala, anterior cingulate, orbitofrontal cortices, and insula (Izard, 2019), (see figure 3). Emotional regulation is developed throughout different stages of life from babies, and adolescence to adults, and is essential for navigating life. There is a clear bidirectional link between emotion and sleep and how the quality of sleep impacts daily emotional regulation (Vandekerckhove & Wang, 2017). Sleep impacts emotional memory processing, encoding, memory formation, memory consolidation, mood, emotional brain reactivity, and dreams (Walker & van der Helm, 2009) .

A current issue that has become prevalent in sleep onset is sleep disorders in adults causing mental and physical health problems (Worley, 2018). There are eighty-one sleep disorders in eight categories (Thorpy, 2012) including insomnia, sleep-related breathing disorders, hypersomnias of central origin, circadian rhythm sleep disorders, parasomnias, sleep-related movement disorders, isolated disorders, and other sleep disorders (Thorpy, 2012). Poor sleep is detrimental to mental and physical health due to emotional dysregulation which impacts daily mood, causing anxiety and depression if poorly managed (Vandekerckhove & Wang, 2017). NREM and REM play a crucial role in emotional regulation by processing daily events, memories, emotions, and stressors. For example, when a child is deprived of sleep or receives constant inadequate sleep feelings of anger, frustration, aggression, and confusion are heightened (Vandekerckhove & Wang, 2017) resulting in psychiatric disorders. Sleep disturbances and disorders, for example, insomnia and sleep apnea are prevalent in adults which affect social function and negative emotional reactivity (Vandekerckhove & Wang, 2017). Emotional reactivation and processing occur during REM sleep through the amygdala and hippocampus by theta waves integrating experiences into memory structures (Werner et al., 2020).

What is sleep-forget, sleep to remember theory?

Figure 4. Limbic system

The sleep-forget, sleep-to-remember theory (SFSR) suggests emotions need to be processed the first night during REM after an emotional event otherwise failure to process will lead to further attempts to downregulate emotional responses in future nights of sleep (Werner et al., 2020). Stress and traumatic experiences affect emotional processing because of the excitation and reactivation of the limbic system. The limbic system's function (see figure 4) is to regulate emotions and behaviour by processing memory and thoughts during wakefulness and then reprocessing during the night (Vandekerckhove & Wang, 2017). When sleep deprivation of REM occurs, the limbic system fails during the day, causing an increase in emotional irritability and negative reactions to stress or aversive situations (Vandekerckhove & Wang, 2017). Emotional processing also occurs in dreams during REM sleep with increased activity in the subcortical brain including the amygdala, striatum, and hippocampus, and cortical areas including the medial prefrontal cortex, mPFC. Dreams are where the downregulation of emotions occur, in particular arousing emotions occurs, for example when painful and aversive emotions arise. During REM the amygdala and cingulate cortex can process emotions through the medial prefrontal cortex which is regulated by the limbic system (Vandekerckhove & Wang, 2017). SFSR theory reaffirms the importance of receiving a cycle of NREM and REM sleep on the first night when a stressful event occurs to help emotional and memory processing.

What is the Threat Stimulation Theory?

Mini case study

It is the night before the 2024 local footy grandfinal. Shaun is lying in bed trying to fall asleep but he is experiencing stress and anxiety because he does not want to play bad. His heart rate is increasing and body temperature is hot.

Similarly, the Threat Stimulation theory (TST) proposes that in REM sleep, dreams are organised in distinct neural pathways in perception to waking consciousness (Valli et al., 2005). Negative emotions of fear and anger are frequently experienced in dreams which is evidence showing that dreams are affected by PTSD and life-threatening events, in children and adults. (Valli et al., 2005). However when sleep disturbances and disorders are active for example insomnia, and sleep apnea the emotional processing is dysfunctional through SFSR (Werner et al., 2020), and TST (Valli et al., 2005) due to insufficient and poor quality REM sleep. The bidirectional effect of emotion and sleep is demonstrated with acute stress, for example, anxiety before an exam, surgery, or a social event, negatively affects REM. Stress causes the body to frequently wake up in N1, and N2 (light sleep) due to elevated increased temperature and heart rate due to the fear response, preparing the body mentally and physically for a fight or flight response. Research shows that insomnia has a strong correlation between the arousal of emotions and daytime events that cause sleep disturbances. Research has also shown insomnia develops into adulthood if a child experiences constant daily stress within their environment, especially if the emotions are repressed and mismanaged. Therefore the SFSR theory and TST demonstrate how REM and dreaming it critical for emotional memory and processing and how insomnia can be developed if an individual is receiving poor, interrupted sleep. Cartwright also demonstrated that depression can be improved by adequate REM sleep as depressed participants reported an improvement in mood after dreaming (Cartwright., et, al 1991). When sleep deprivation occurs it affects emotional memory formation by impairing the long-term potential (LTP) which results in avoidance of learning and taste aversion because the excitability of hippocampal neurons is reduced. Therefore highlighting that poor sleep can negatively impact daily learning functions and can make a person more avoidant, lacking confidence and energy to try new skills and emphasising that a good night’s sleep is important for the subcortical brain to make new memory formations.

How do sleep disorders affect emotion?

However, sleep disruptions to REM are also caused by biological sleep disorders for example sleep apnea (Cunningham et al., 2022). Obstructive sleep apnea is a disorder where breathing starts and stops repeatedly in sleep correlated with loud snoring. OSA affects 1 billion people worldwide, commonly affecting middle-aged individuals (Cunningham et al., 2022). OSA causes poor sleep and cognitive deficits which have detrimental effects on mental and physical health leading to depression, and anxiety (Cunningham et al., 2022). 116 participants who experience OSA had less respiratory control in REM compared to NREM (Bonsignore et al., 2024). Moderate to severe REM OSA is associated with hypertension and metabolic abnormalities such as metabolic syndrome and diabetes and not depression (Bonsignore et al., 2024). Interestingly insomina[spelling?] is higher in females (Bonsignore et al., 2024). Sleep apnea and insomnia are associated with depression and anxiety (Bonsignore et al., 2024) therefore OSA harms the consolidation of emotional processing during sleep. Sleep onset optimisation allows time for the body to emotionally regulate in REM through the medial prefrontal cortex and amygdala connections (Vandekerckhove & Wang, 2017) which allows the body to execute daily functions. The communication is executed at a cellular level for example clock genes BMAL1 and CLOCK which talk to the suprachiasmatic nucleus innervate (SCN) in the hypothalamus through transcription and translation of clock genes and the feedback loop. The hypothalamus physically responds to emotion through the sympathetic nervous system by activating the flight or fight system causing hypertension of blood vessels, elevated heart rate, dry mouth, and sweating. When the SCN is disrupted by sleep deprivation due to poor sleep hygiene the body struggles to regulate stress and emotions throughout the day causing mental health challenges.

Techniques to assist in falling asleep promptly:

Optimisation is making the most out of a situation. Therefore sleep onset optimisation is the decision to prioritise the opportunity to have the best sleep possible each night (Worley, 2018). Establishing healthy sleep techniques will promote the circadian process of NREM, and REM and assist in falling asleep promptly to improve overall physical and mental health, emotional regulation, and daily motivation (Markwald et al., 2018). Techniques include establishing a good bedtime routine and sleep environment by limiting screen time, caffeine, and alcohol while increasing self-care through exercise, mindfulness activities, and healthy eating (Billings et al., 2020), (Markwald et al., 2018).

How does the environment affect sleep onset optimisation?

Figure 5. NREM, stage 1 of sleep. N1 is hard to activate if body temperature and heart rate is high.

The environment where a person conducts their bedtime routine is the first technique that promotes sleep onset optimisation (Billings et al., 2020). The built, natural, and ambient environment impacts heavily on the quality of sleep obtained throughout the night (Billings et al., 2020). For example, if the sound, light, temperature, humidity, and atmosphere within and around the room are too high, the body will increase heart rate, blood flow, and cortisol (Billings et al., 2020). Therefore when the room temperature is too high, it causes the body to heat up creating difficulty falling asleep in stage N1 due to the role of N1 is to cool the body down and decrease the heart rate (see figure 5), (Carskadon& Dement, 2011), (Colten & Altevogt, 2015). This is shown in insomnia which is a sleep disorder detrimental to daily emotional regulation and motivation. The lack of sleep within insomnia is commonly due to stress because the body is determining whether to fight or flight for the next day. Hence the racing heart rate, which is going against the body N1 in trying to get internal body temperature to drop and heart rate to decrease. Individuals with insomnia usually experience heightened anxiety, stress, and emotions when they put their heads on the pillow. Lack of sleep causes low concentration and motivation. For example, university students who are suffering from insomnia then have to try to find energy to get themselves to class, with the hardest part being to concentrate, pay attention, and be engaged. Techniques to promote sleep onset optimisation for sleep disorders including insomnia are constantly being researched. Sleep hygiene is highly recommended for example limiting coffee, alcohol, and smoking while increasing physical exercise during the day but avoiding exercise at night[factual?]. Sleep environment is important for sleep onset optimisation [grammar?] for example a quiet, dark room that is not too hot or cold due to the body trying to regulate itself in NREM. Another technique for sleep onset optimisation is limiting screen time at night, for example, an hour before bed, which helps melatonin and SCN activate the feeling of sleepiness[factual?]. Sleep restriction or sleep consolidation (Rossman, 2019) helps reduce the worry and stress about not receiving enough sleep when the person goes to bed (Rossman, 2019) time therapy has been proven to help insomnia by restricting the actual sleep time and also keeping a sleep diary for example if a person has not fallen asleep within thirty minutes (Markwald et al., 2018) , the recommendation is to get out of bed or only going to bed when the feeling of sleepiness arises (Markwald et al., 2018).

What techniques promote sleep onset optimisation for insomnia?

Mini case study

An hour has passed, and Shaun is still lying wide awake, going over all the plays and goals for tomorrows[grammar?] grand-final. He glanced at his phone to check the time and it is now 01:00 am. He decided to google some techniques that can help his body relax.

Stimulus control has also been seen to be beneficial for insomniacs by having a bed and bedroom just to sleep in (Rossman, 2019). Therefore stimulus control encourages all activities besides sleeping and sex to be in another room (Rossman, 2019) this includes wind down activities like watching a TV show, reading a book, or having a nice beverage (Rossman, 2019). When a person experiences a consistent lack of sleep, there is high stress around going to bed which is shown through sleep consolidation, however using cognitive restructuring around negative thoughts situated around bedtime and going to sleep can help promote sleep onset (Rossman, 2019). Relaxation techniques before bed are important to implement for good sleep hygiene. Progressive muscle relaxation helps the body in the N1 and N2 stages and helps the brain think about contracting muscles instead of focusing on thoughts. By contracting and releasing the muscles it also helps the body relax. Cognitive behavioural therapy for insomnia (CBT-i) is more beneficial than taking sleep medication (Rossman, 2019). Mindfulness before bed is beneficial because it brings attention to thoughts of the day, stressors, emotions, and goals for the next day which is important to track (Rossman, 2019), especially for insomniacs and anyone who experiencing sleep deprivation (Rossman, 2019). However, mindfulness techniques before bed do not work for everyone which is a normal process. Exercise, particularly aerobic exercise has been proven to reduce bedtime anxiety highlighted in sleep consolidation (Passos et al., 2010), (Rossman, 2019). Passos found an increase in stages 3 and 4 of NREM (Passos et al., 2010). However, a limitation of Passos's study is that it was for chronic primary insomnia (Passos et al., 2010). Insomnia and lack of sleep also affect the menstrual cycle and digestive issues which suggests further studies (Passos et al., 2010). A potential limitation of exercise to reduce sleep anxiety for insomniacs is age, for example, if an elderly person has movement restrictions or disabilities, exercise would not be a suitable technique (Passos et al., 2010). Therefore further implications for techniques besides mindfulnesses need to be established that are applicable for all ages who are suffering from sleep deprivation.

What techniques promote sleep onset optimisation for sleep apnea?

Figure 6. CPAP an example of a physical external technique used for sleep apnea.

The built environment includes the location of the house and the surroundings (Billings et al., 2020). For example, access to parks, recreational facilities, bike lanes, street connectivity, and walking trials[spelling?] promote exercise and healthy daily routines which promotes sleep onset optimisation at nighttime. (Billings et al., 2020) The built environment positively correlates with breathing sleep disorders for example sleep apnea (Billings et al., 2020). One technique to promote sleep onset optimisation for sleep apnea is exercise, especially in adults who experience a high BMI (Billings et al., 2020). However, lifestyle techniques to promote sleep onset optimisation for sleep apnea are limited with regards to children (Jun et al., 2016) especially when a child is emotionally regulated and motivated but their brain wakes up thirty times during the night.The anatomic factors of sleep apnea include micrognathia, retrognathia, facial elongation, mandibular hypoplasia, displacement of the hyoid and adenoid, and tonsillar hypertrophy (very common in children) (Shneerson & Wright, 2001). One major successful technique to promote sleep onset optimisation for sleep apnea is surgery particularly for adenoid and tonsillar hypertrophy (Aboussouan et al., 2023). A limitation of determining whether a child needs to have surgery to address anatomic factors is the financial income or education of a family (Aboussouan et al., 2023). A basic technique that can help sleep onset optimisation is positional sleep therapy by reducing the amount of time woken up 6.4 times (Aboussouan et al., 2023). Sleep apnea is known to be a common disorder in adults over fifty and is commonly linked to alcohol (Aboussouan et al., 2023). Therefore another technique to optimise sleep is alcohol avoidance (Aboussouan et al., 2023). The lack of oxygen is the main cause of sleep apnea which causes disturbances of the brain. Therefore CPAP is beneficial for sleep apnea patients because it also reduces blood pressure which is common in adults (see figure 7)(Aboussouan et al., 2023).

Quiz

Conclusion

To be motivated in life and emotionally regulated throughout the day it is important to promote a good night through techniques that assist and promote sleep onset optimisation. The quality of sleep displayed in REM and NREM impacts how a person stays emotionally regulated throughout the day. When sleep deprivation is prevalent, mental physical, and sleep disorder challenges and health issues arise which is highlighted through insomnia and sleep apnea. The sleep-forget, sleep-to-remember theory (SFSR) and threat stimulation theory (TST) show the bi-directional impact of sleep and emotions in different regions of the brain specifically emotional processing and memory formation. Furthermore, sleep onset optimisation is critical for daily motivation beginning with basic physiological motivation to psychosocial motivation within school, work, university, and personal goals. There is a vast range of techniques to assist in falling asleep promptly to ensure sleep onset optimisation is being achieved throughout the night to decrease sleep deprivation and improve daily motivation and emotional regulation for a healthy life regardless of the stress that is caused due to the physical and mental demands of life.

References

Aboussouan, L. S., Bhat, A., Coy, T., & Kominsky, A. (2023). Treatments for obstructive sleep apnea: CPAP and beyond. Cleveland Clinic Journal of Medicine, 90(12), 755–765. https://doi.org/10.3949/ccjm.90a.23032

Alhola, P., & Polo-Kantola, P. (2007). Sleep deprivation: Impact on cognitive performance. Neuropsychiatric Disease and Treatment, 3(5), 553–567. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2656292/

Araújo, D., Brymer, E., Brito, H., Withagen, R., & Davids, K. (2019). The empowering variability of affordances of nature: Why do exercisers feel better after performing the same exercise in natural environments than in indoor environments? Psychology of Sport and Exercise, 42, 138–145. https://doi.org/10.1016/j.psychsport.2018.12.020

Axelsson, J., Ingre, M., Kecklund, G., Lekander, M., Wright, K. P., & Sundelin, T. (2019). Sleepiness as motivation: a potential mechanism for how sleep deprivation affects behavior. Sleep, 43(6). https://doi.org/10.1093/sleep/zsz291

Bonsignore, M. R., Mazzuca, E., Baiamonte, P., Bouckaert, B., Verbeke, W., & Pevernagie, D. A. (2024). REM sleep obstructive sleep apnoea. European Respiratory Review, 33(171). https://doi.org/10.1183/16000617.0166-2023

Colten, H. R., & Altevogt, B. M. (2015). Sleep Physiology. Nih.gov; National Academies Press (US). https://www.ncbi.nlm.nih.gov/books/NBK19956/

Cunningham, T. J., Kishore, D., Guo, M., Igue, M., Malhotra, A., Stickgold, R., & Djonlagic, I. (2022). The Effect of Obstructive Sleep Apnea on Sleep-Dependent Emotional Memory Consolidation. Annals of the American Thoracic Society. https://doi.org/10.1513/annalsats.202204-315oc

Dai, C., Zhang, Y., Cai, X., Peng, Z., Zhang, L., Shao, Y., & Wang, C. (2020). Effects of Sleep Deprivation on Working Memory: Change in Functional Connectivity Between the Dorsal Attention, Default Mode, and Fronto-Parietal Networks. Frontiers in Human Neuroscience, 14. https://doi.org/10.3389/fnhum.2020.00360

Frenda, S. J., & Fenn, K. M. (2016). Sleep Less, Think Worse: The Effect of Sleep Deprivation on Working Memory. Journal of Applied Research in Memory and Cognition, 5(4), 463–469. https://doi.org/10.1016/j.jarmac.2016.10.001

Grogan, J. P., Randhawa, G., Kim, M., & Manohar, S. G. (2022). Motivation improves working memory by two processes: Prioritisation and retrieval thresholds. Cognitive Psychology, 135, 101472. https://doi.org/10.1016/j.cogpsych.2022.101472

Izard, C. E. (2019). Emotion Theory and Research: Highlights, Unanswered Questions, and Emerging Issues. Annual Review of Psychology, 60(1), 1–25. https://doi.org/10.1146/annurev.psych.60.110707.163539

Jun, J. C., Chopra, S., & Schwartz, A. R. (2016). Sleep apnoea. European Respiratory Review, 25(139), 12–18. https://doi.org/10.1183/16000617.0077-2015

Kim, S. (2013). Neuroscientific Model of Motivational Process. Frontiers in Psychology, 4(98). https://doi.org/10.3389/fpsyg.2013.00098

Kosuke Kaida, Mori, I., Kihara, K., & Naoko Kaida. (2023). The function of REM and NREM sleep on memory distortion and consolidation. Neurobiology of Learning and Memory, 107811–107811. https://doi.org/10.1016/j.nlm.2023.107811

Liu, Z., Wang, Y., Cai, L., Li, Y.-Z., Chen, B., Dong, Y., & Huang, Y. H. (2016). Prefrontal Cortex to Accumbens Projections in Sleep Regulation of Reward. 36(30), 7897–7910. https://doi.org/10.1523/jneurosci.0347-16.2016

Markwald, R. R., Iftikhar, I., & Youngstedt, S. D. (2018). Behavioral Strategies, Including Exercise, for Addressing Insomnia. ACSM’s Health & Fitness Journal, 22(2), 23–29. https://doi.org/10.1249/FIT.0000000000000375

Massar, S. A. A., Lim, J., & Huettel, S. A. (2019). Sleep deprivation, effort allocation and performance. Sleep Deprivation and Cognition, 246, 1–26. https://doi.org/10.1016/bs.pbr.2019.03.007

Morris, L. S., Grehl, M. M., Rutter, S. B., Mehta, M., & Westwater, M. L. (2022). On what motivates us: A detailed review of intrinsic v. extrinsic motivation. Psychological Medicine, 52(10), 1–16. https://doi.org/10.1017/S0033291722001611

Mu, P., & Huang, Y. H. (2019). Cholinergic system in sleep regulation of emotion and motivation. Pharmacological Research, 143, 113–118. https://doi.org/10.1016/j.phrs.2019.03.013

Passos, G. S., Poyares, D., Santana, M. G., Garbuio, S. A., Tufik, S., & Mello, M. T. (2010). Effect of acute physical exercise on patients with chronic primary insomnia. Journal of Clinical Sleep Medicine : JCSM : Official Publication of the American Academy of Sleep Medicine, 6(3), 270–275. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2883039/

Ramar, K., Malhotra, R. K., Carden, K. A., Martin, J. L., Abbasi-Feinberg, F., Aurora, R. N., Kapur, V. K., Olson, E. J., Rosen, C. L., Rowley, J. A., Shelgikar, A. V., & Trotti, L. M. (2021). Sleep is essential to health: an American Academy of Sleep Medicine position statement. Journal of Clinical Sleep Medicine, 17(10), 2115–2119. https://doi.org/10.5664/jcsm.9476

Robinson, J. (2022, November 16). What Are REM and Non-REM Sleep? WebMD; WebMD. https://www.webmd.com/sleep-disorders/sleep-101

Rossman, J. (2019). Cognitive-Behavioral Therapy for Insomnia: An Effective and Underutilized Treatment for Insomnia. American Journal of Lifestyle Medicine, 13(6), 544–547. https://doi.org/10.1177/1559827619867677

Roth, T. (2007). Insomnia: definition, prevalence, etiology, and Consequences. Journal of Clinical Sleep Medicine : JCSM : Official Publication of the American Academy of Sleep Medicine, 3(5), 7–10. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1978319/

Schutte, N. S., & Malouff, J. M. (2015). General and Realm-Specific Self-Efficacy: Connections to Life Functioning. Current Psychology, 35(3), 361–369. https://doi.org/10.1007/s12144-014-9301-y

Shneerson, J., & Wright, J. J. (2001). Lifestyle modification for obstructive sleep apnoea. Cochrane Database of Systematic Reviews. https://doi.org/10.1002/14651858.cd002875

Thorpy, M. J. (2012). Classification of Sleep Disorders. Neurotherapeutics, 9(4), 687–701. https://doi.org/10.1007/s13311-012-0145-6

Valli, K., Revonsuo, A., Pälkäs, O., Ismail, K. H., Ali, K. J., & Punamäki, R.-L. (2005). The threat simulation theory of the evolutionary function of dreaming: Evidence from dreams of traumatized children. Consciousness and Cognition, 14(1), 188–218. https://doi.org/10.1016/S1053-8100(03)00019-9

Vandekerckhove, M., & Wang, Y. (2017). Emotion, emotion regulation and sleep: An intimate relationship. AIMS Neuroscience, 5(1), 1–17. https://doi.org/10.3934/Neuroscience.2018.1.1

Vyazovskiy, V. (2015). Sleep, recovery, and metaregulation: explaining the benefits of sleep. Nature and Science of Sleep, 7(7), 171. https://doi.org/10.2147/nss.s54036

Walker, M. P., & van der Helm, E. (2009). Overnight therapy? The role of sleep in emotional brain processing. Psychological Bulletin, 135(5), 731–748. https://doi.org/10.1037/a0016570

Werner, G. G., Schabus, M., Blechert, J., & Wilhelm, F. H. (2020). Differential Effects of REM Sleep on Emotional Processing: Initial Evidence for Increased Short-term Emotional Responses and Reduced Long-term Intrusive Memories. Behavioral Sleep Medicine, 19(1), 1–16. https://doi.org/10.1080/15402002.2020.1713134

Worley, S. L. (2018). The Extraordinary Importance of Sleep: The Detrimental Effects of Inadequate Sleep on Health and Public Safety Drive an Explosion of Sleep Research. P & T : A Peer-Reviewed Journal for Formulary Management, 43(12), 758–763. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6281147/

External links

Exercising for better sleep (John Hoskins)
Exercise and insomnia (Sleep foundation)
Sleep and emotions (News Medical)
Sleep and motivation (Ever Sleep)