Sleep Series – Part 3: Getting a Better Night’s Sleep
Sleep disturbances are one of the most common causes of suffering among people living with chronic pain. Whilst pain itself directly affects getting and staying asleep; poor sleep feeds into the pain cycle, only exacerbating pain.
In this Sleep Series we will look at: understanding sleep, understanding sleep disturbances and how you can get a better night’s sleep. Welcome to Part 3: Getting a Better Night’s Sleep.
Part 3: Getting a Better Night’s Sleep
Have you ever spent the night watching the second hand flick its way through the minutes and hours? All the while, your brain anxiously worrying how you are going to get through the endless to-do list of the day to follow. As the new day dawns, you find yourself grumpier, hungrier and tireder than usual; and to top things off your pain is far worse. This article will answer how to get a better night’s sleep based on current research.
In this final article of our 3-part sleep series we will discuss:
- Why is sleep so important?
- What the research says about alcohol, caffeine, diet, exercise and smoking when it comes to sleep?
- How to get a better night’s sleep?
- What is sleep hygiene and why is it important for getting a better night’s sleep?
- What is sleep restriction and why is it important for getting a better night’s sleep?
- What is stimulus control therapy and why is it important for getting a better night’s sleep?
- A better night’s sleep. What does your day and night look like?
- Free tools to help you manage sleep
Why is sleep so important?
We all know sleep is important, we can feel its importance as we lie wide awake in bed, or as we struggle through the day after a bad night’s sleep.
Research has shown:
- That a good quality sleep reduces the risk of obesity, type 2 diabetes, Alzheimer’s, depression, and numerous other diseases.
- The strong link between chronic pain and sleep, in particular a poor quality sleep and changes to pain sensitivity, tolerance, perception, and interference.
The reasons for this vast array of health issues or benefits, is because sleep affects every cell in your body, allowing us to:
- Consolidate our memories (learn more here)
- Communicate with others more effectively (learn more here)
- Manage our stress levels (learn more here)
- Maintain our self-control (learn more here)
- Maintain healthy habits such as diets and exercise (learn more here)
- Think rationally (learn more here)
- Reduce risk taking behaviour, especially on the road (learn more here)
- Focus and concentrate (learn more here)
- Regulate our emotions (learn more here)
- Be compassionate, empathetic and show care towards others (learn more here)
- Maintain normal levels of hunger and appetite (learn more here)
- Maintain our hormone levels and metabolism (learn more here)
- Reduce pain sensitivity and increase pain tolerance (learn more here)
- Improve our immune system and the production of cytokines (learn more here)
- Maintain our glymphatic system and removal of waste products from the brain and nervous system (learn more here)
- Improve out gut health and the microbiome (learn more here)
What the research says about alcohol, caffeine, daytime napping, diet, exercise and smoking when it comes to sleep?
It’s incredibly hard to change a behaviour when you are unsure why you need to. It is also incredibly difficult to get a good night’s sleep when you don’t realise the role some of your choices play in preventing you from sleeping.
In this section we will outline what the research says about: alcohol, caffeine, daytime napping, diet, exercise and smoking.
- Alcohol: most research suggests that you shouldn’t drink alcohol of an evening if you are struggling with your sleep. Whilst you may fall asleep earlier, your sleep quality is affected and fragmented. Interestingly, this seems to apply more to heavy drinkers. Light to medium drinkers may benefit from a single glass of red wine per night – both for sleep and reducing risk of dementia.
- Tip: It is recommended that if you suffer from insomnia and drink every night, to limit alcohol intake and see if this brings about an improvement.
- Caffeine: researchers have found that caffeine has different effects on different people. The average half-life of caffeine is roughly 5hrs, meaning it can keep you awake long after the final cup. Researchers have found people who metabolise caffeine quickly, can be virtually unaffected by its affects, and drink it anytime day or night; where as those who metabolise caffeine slowly, can be affected for 9-12hrs beyond this cup of coffee.
- Tip: If you are struggling to sleep, then it might be worth limiting caffeine to an early morning cup, or removing it entirely from your diet and see if it works.
- Daytime napping: researchers have shown that the optimal time for a nap is roughly 7hrs after you wake, it should be long enough to feel refreshed but not long enough to fall into a deep sleep. Falling into a deep sleep nap can be responsible for affecting the drive to sleep at night, mood and levels of drowsiness after your nap.
- Tip: According to research, the optimal time for a nap is roughly 20-40mins, approximately 7hrs after you wake up.
- Exercise: researchers have shown that even as little as 10mins of exercise a day leads to a better night’s sleep. Adding some resistance training, not only increases muscle mass, research suggests it improves all aspects of sleep, particularly sleep quality as you age. Once again, much like caffeine different people respond differently to exercise; with research suggesting, some may be stimulated and unable to sleep after an intense workout, and others finding it an essential part of their evening wind-down.
- Tip: If you are struggling to sleep at night it might be worth avoiding exercise after 5pm, or moving it entirely to the morning and see if that helps.
- Diet: As we have already highlighted, diet plays a vital role when it comes to sleep. One of the most popular diets – the Mediterranean Diet – has been widely researched and has been shown to improve sleep, especially as we age. The reason for this may lie in:
- Being high in fibre and protein, which is associated with deep sleep (research)
- Being low in sugar and carbs, which is associated with fragmented sleep (research)
- Being primarily plant-based, which is associated with improved mental and emotional health (research)
- Improving gut health, which is associated with weight, mood and sleep quality (research)
- Reducing risk of heart disease, diabetes, obesity, dementia and some types of cancer (research)
- Diet: another area researchers have looked into includes time restricted eating (TRI). TRI is thought to assist sleep due to the affects meals have on our core temperature. Our body temperature naturally falls as night time approaches, which allows sleep to be initiated. When we eat our digestive system starts back up and raises our body temperature, potentially inhibiting our sleep drive.
- Tip: If you often eat before bed, it might be worth moving your eating window earlier in the evening and seeing if changing your meal times helps you get to sleep earlier.
How to get a better night’s sleep?
Getting a better night’s sleep breaks down into 3 key factors:
- Your appetite for sleep (sleep drive): this is an energy tank that is depleted over the day: it is at its peak in the morning and lowest prior to bed. Sleep drive is based on our sleep-wake cycle and can be impacted by having an afternoon snooze, drinking a cup of coffee or oversleeping in the morning.
- Your body clock (circadian rhythm): this clock operates over a 24hr timeframe and works in unison with our digestion, body temperature and sleep. As we wake our levels of alertness coincide with our hunger, digestion and an increased body temperature. As we prepare for bed, we become drowsy, drop our body temperature and reduce our hunger levels and digestion. Our body clock can be impacted by sleep patterns, light exposure, meal times and jet lag.
- Your levels of stimulation or arousal: the ability to switch off is vital when it comes to getting and staying asleep. Having an active mind, often leads to the release of hormones in our body such as adrenaline and cortisol, neither of which assists us with falling asleep. Our levels of stimulation are impacted by life worries, worries about sleep or lack of it, and sleep effort – which is when we actively try to force ourselves to get to sleep.
These 3 key factors are why research suggests the strategies of: sleep hygiene, sleep restriction and stimulus control therapy can be beneficial with getting a better night’s sleep. When it comes to mild sleep disturbances: using sleep hygiene and/or stimulus control may be sufficient to getting a better night’s sleep; but for chronic insomnia: often all three strategies need to be implemented.
What is sleep hygiene and why is it important for getting a better night’s sleep?
Before explaining sleep hygiene, let’s quickly recap on sleep efficiency. Sleep efficiency is a way of working out the percentage of time you spend asleep, in relation to the percentage of time spent in bed. The way it is calculated is by dividing total sleep time, by total time in bed. Normal sleep efficiency is considered 85%. In short, this means you are sleeping for a majority of the time you spend in bed.
Sleep hygiene involves cleaning up your unhealthy habits when it comes to sleep; with the aim of helping you get a better-quality sleep and reducing your daytime sleepiness.
The most important aspect of sleep hygiene is improving your sleep efficiency. The best way to improve sleep efficiency includes a combination of sleep restriction (which we discuss below) and sleep hygiene practices, including:
- Limit daytime naps. Research suggests a short 20-40 min nap, approximately 7hours after waking can help improve mood, alertness and performance. Although naps do not make up for lack of night time sleep, they can get your through the day.
- Avoid stimulants after 2pm. Research suggest if you are sensitive to coffee and having trouble sleeping it is worth cutting back, stopping earlier or ceasing caffeine all together.
- Exercise earlier in the day. Research suggests exercising first thing in the morning wakes you up and helps you sleep. If you do exercise in the evening it might be worth finishing 3hrs before bedtime.
- Clean up your diet. Research suggests reducing sugar and carbs and increasing fibre and protein may improve sleep quality; it also suggests stopping eating at least 2-3 hours prior to bedtime may assist with getting to sleep.
- Sit in the sunshine. Research suggests getting 30-45mins of direct sunshine each day can assist with better quality sleep at night, this is due to the role sunlight plays in our circadian rhythm – body clock.
- Learn to relax. Research shows that reducing your arousal levels can assist with getting to sleep. An active mind, often leads to an active body – with hormones like cortisol and adrenaline being released and further preventing switching off. Some useful strategies for relaxing can be seen below in the table.
- Create a bedtime routine. Research shows that creating a regular bedtime routine in the 30-60mins leading to going to bed can help your brain create a clear pathway between a set of actions and winding down for sleep. Consistency and repetition are key to making this connection work.
What is sleep restriction and why is it important for getting a better night’s sleep?
People who spend large amounts of time awake in bed (low sleep efficiency), tend to develop a negative association between their bed and sleep, which reinforces the pattern of worry, anxiety and inability to get or stay asleep.
Sleep restriction therapy (SRT) is a type of treatment which tries to improve sleep efficiency by reducing the time spent in bed to “reset or restore” the natural drive to sleep. Research has shown it to be extremely effective in the management of sleep problems, but can be incredibly challenging due to its effects on day-time tiredness, irritability and boredom of a night time.
Please note, it is important before trialing SRT that you check with your doctor and discuss your plan. It is important that you remember your sleep may get worse in first 3-4 days and that you may become more tired or moody in the short-term. If tiredness becomes an issue, you should avoid driving or operating heavy machinery during this time.
An overview of SRT, completed under the guidance of your healthcare team:
- For 1-2 weeks prior to commencing SRT you will need to complete a sleep diary to measure your average sleep time.
- You will cut your time in bed to the average sleep time every night (min. 5hrs, no additional sleep allowed outside this time)
- You will then increase or decrease this sleep time based on your sleep efficiency.
- To calculate you sleep efficiency, record your time spent asleep and divide it by the time spent in bed, then multiply by 100
- If your SE > 90% increase add 15-30mins weekly
- If your SE <80% then drop your sleep time by 15mins
- It may take 4-8 weeks to restore the natural drive to sleep and get a better night’s sleep.
- Note: you should refrain from daytime napping, caffeine use or any other stimulant use during this period.
What is stimulus control therapy and why is it important for getting a better night’s sleep?
Stimulus control therapy (SCT) is an effective treatment used for managing insomnia. It is based around tackling the negative association which occur between:
- Bedtime, the bedroom, nighttime, and
- Negative emotions and thoughts, and
- Being awake.
This is known as conditioned insomnia. SCT works to change specific activities, situations or environments; removing the reinforcement of negative associations, which lead to distress, frustration, racing thoughts, anticipatory anxiety, and physiological and psychological arousal.
SCT teaches the following techniques:
- Go to bed and wake up at the same time. Your body craves regularity and starts to prepare to wake 90mins before it actually wakes you, if it knows when to wake, it knows when to maximise the sleep opportunity before you wake. Go to bed at the same time and follow the same routine which means creating a set of triggers your brain associates with winding down, calming down and getting ready for bed, for example having a shower, stretching for 10mins, brushing your teeth and getting into bed (link)
- Go to bed when you are tired. Adenosine and melatonin are responsible for the drowsy feeling we get at bedtime. Once levels are high enough, our sleep drive kicks in to allow us to get to sleep. Having a consistent bedtime routine and sleep tie, helps our body develop a pattern and habit, allowing us to wind-down and get to sleep (link)
- Get out of bed after 20mins. When you can’t sleep you need to try to be disciplined with going to bed late and when you are tired; waking up early, even if you are tired; not napping during the day, even if you are tired; lowering your stimulation before bed, start calming your nervous system; getting out of bed when you lie there for longer than 20mins; lowering stimulation when you awake during the night; calming your system when you wake, try relaxation, meditation, deep breathing (link)
- Reframe your bedtime thoughts. Sleep worry and sleep effort are to big issues when it comes to bad quality sleep. Sleep worry relates to the anxiety we feel when we don’t sleep, and how we will cope with the day to proceed. Sleep effort relates to the effort we put into actively trying to fall asleep, which often only chases sleep away. The more we struggle, the harder it is to get to sleep. Often letting go and shifting your mindset about not sleeping, brings on sleep much faster (link)
- “Winding down” your mind. Often the first time we stop and process the day is bedtime. Once this cascade of thoughts, worries and stress coming flooding in, we are so wound up we can’t sleep. Scheduling time earlier in the evening to reflect over the day, plan for tomorrow or do a “brain dump” can help you offload and wind-down you mind long before bed (link)
- Avoid technology. The jury is out whether the “blue light” of technology is the cause of poor sleep – as it affects melatonin release – or the stimulation from technology use is the cause of poor sleep. Either way, reducing your use of technology in the 1-2hrs prior to bedtime may assist with a better night’s sleep (link)
- Make your bedroom a sanctuary for sleep. Studies have shown that the perfect sleep environment sets you up for success with sleep, this is a room that is very dark; not an office, gym, games room or cinema; it is silent; has fresh air and ventilation to remove carbon dioxide from the air; it is around 16-18 degrees; your bed is a single bed, with a firm mattress, good supportive pillow and a quilt that is not too heavy, hot or light, cold (link)
A better night’s sleep. What does your day and night look like?
According to research, if you are struggling with getting to sleep, staying asleep or waking too early, it might be worth trying the following steps:
- During the Day:
- Set a strict wake up time
- Minimise caffeine after 2pm
- Avoid napping – where possible, avoid napping, as it can affect your night’s sleep.
- Exercise in the morning – where possible, exercise moderately earlier in the day.
- Before bedtime
- Reduce vigorous physical activity 4-6hrs prior to bedtime
- Reduce moderate physical activity 2-4hrs prior to bedtime
- Avoid meals, caffeine and alcohol 2-3hrs prior to bedtime
- Avoid cold baths 2hrs prior to bedtime
- Avoid hot baths 2hrs prior to bedtime
- Avoid bright lights, technology, stimulation or arguing 2hrs prior to bedtime
- At bedtime:
- Create a relaxing bedtime routine in the 1hr prior to bedtime
- Write down your worries, a to-do list for tomorrow and what you a grateful 1-2hrs prior to bedtime
- Turn down your lights in the 1-2hrs prior to bedtime
- Go to bed when you are tired, don’t postpone it
- Set a strict bedtime
- Try to sleep in the same bed each night – ensure it is comfortable
- Keep your room dark, quiet and around 16-18 degrees
- Get out of bed if you lie awake for longer than 20-30mins
- Keep stimulation/arousal levels low whilst awake during the night
- Other tips
- Keep your bedroom for sleep and sex, nothing else
- Work on stress management and time management strategies to manage anxiety, worries and emotional distress
- Speak with your doctor, psychologist or healthcare team
Free tools for managing sleep
- My Sleep Well: Sleep efficiency calculator here
- Sleep Education: Sleep latency test explained
- Workbook: Patient Handout: Insomnia patient handout (link)
- Worksheet: Sleep Australia: Sleep Diary (link)
- Worksheet: CCI: Sleep Diary (link)
- Worksheet: National Sleep Foundation: Sleep Diary (link)
- Worksheet: Sleep Awareness Week: Sleep Diary (link)
- Worksheet: AASM: 2 Week Sleep Diary (link)
- Worksheet: DAS: Insomnia Management Kit (link)
- Worksheet: DAS: Bedtime Restriction Therapy (link)
- Worksheet: Psychology Tools: Sleep-Wake Disorders Worksheets (link)
- Worksheet: Psychology Tools: Sleep Restriction Worksheets (link)
- 2019 Australian Report: Chronic insomnia disorder in Australia (link here)
- Journal Article: The association of sleep and pain: An update and a path forward (link here)
- Journal Article: Extent and Health Consequences of Chronic Sleep Loss and Sleep Disorders (link here)
- 2019 PARLIAMENT OF THE COMMONWEALTH OF AUSTRALIA: Bedtime Reading. Inquiry into Sleep Health Awareness in Australia (link here)
- Journal Article: Sleep and health (link here)
- Fact Sheets: The Australian Sleep Foundation (link here)
- Journal Article: Effects of Diet on Sleep Quality (link here)
- Journal Article: Effects of Resistance Exercise Timing on Sleep Architecture and Nocturnal Blood Pressure (link here)
- Journal Article: The Role of Sleep Hygiene in Promoting Public Health: A Review of Empirical Evidence (link here)
- Journal Article: Behavioral interventions for insomnia: Theory and practice (link here)
- Journal Article: Fasting, circadian rhythms, and time restricted feeding in healthy lifespan (link here)
- Journal Article: The Glymphatic System: A Beginner’s Guide (link here)
- Journal Article: Cytokine Production during Sleep and Wakef ulness and Its Relationship to Cortisol in Healthy Humans (link here)
- Journal Article: Effects of Sleep on the Production of Cytokines in Humans (link here)
- Journal Article: Sleep Duration Predicts Cardiovascular Outcomes: A Systematic Review and Meta-Analysis of Prospective Studies (link here)
- Journal Article: Association between Insomnia and Metabolic Syndrome in a Chinese Han Population: A Cross-sectional Study (link here)
- Journal Article: The Effects of Partial Sleep Deprivation on Energy Balance: A Systematic Review and Meta-Analysis (link here)
- Journal Article: Acute Sleep Deprivation and Culpable Motor Vehicle Crash Involvement (link here)
- Journal Article: Gut Microbiome Diversity Is Associated With Sleep Physiology in Humans (link here)
- Journal Article: Fiber and Saturated Fat Are Associated with Sleep Arousals and Slow Wave Sleep (link here)
- Journal Article: Mediterranean diet pattern and sleep duration and insomnia symptoms in the Multi-Ethnic Study of Atherosclerosis (link here)
- Journal Article: Adherence to the Mediterranean Diet Is Associated With Better Sleep Quality in Italian Adults (link here)
- Journal Article: Primary Prevention of Cardiovascular Disease with a Mediterranean Diet (link here)
- Journal Article: Health Benefits of the Mediterranean Diet: An Update of Research Over the Last 5 Years (link here)
- Journal Article: Ghrelin, Sleep Reduction and Evening Preference: Relationships to CLOCK 3111 T/C SNP and Weight Loss (link here)
- Journal Article: Plant-Based Diets: Reducing Cardiovascular Risk by Improving Sleep Quality? (link here)
- Journal Article: Development of a sleep diary for chronic pain patients (link here)
- Journal Article: Blocking nocturnal blue light for insomnia: A randomized controlled trial (link here)
- Journal Article: Activity, arousal, and the MSLT in patients with insomnia (link here)
- Journal Article: Sleep hygiene or compensatory sleep practices: An examination of behaviours affecting sleep in older adults (link here)
- Journal Article: Stress-induced insomnia: opioid-dopamine interactions (link here)
- Journal Article: Prevalence of Sleep Disturbance in Patients With Low Back Pain (link here)
- Journal Article: Prevalence of Sleep Deprivation in Patients With Chronic Neck and Back Pain: A Retrospective Evaluation of 1016 Patients (link here)
- Journal Article: Osteoarthritis and Sleep: The Johnston County Osteoarthritis Project (link here)
- Journal Article: Insufficient Sleep—A Population-Based Study in Adults (link here)
- Journal Article: Cigarette Smoking and Sleep Disturbance (link here)
- Journal Article: Polysomnographic sleep disturbances in nicotine, caffeine, alcohol, cocaine, opioid, and cannabis use: A focused review (link here)
- Journal Article: The bidirectional relationship between exercise and sleep: Implications for exercise adherence and sleep improvement (link here)
- Journal Article: Exploring the Nap Paradox: Are Mid-Day Sleep Bouts a Friend or Foe? (link here)
- Journal Article: Understanding the Sleep-Wake Cycle: Sleep, Insomnia, and the Orexin System (link here)
- Journal Article: The bidirectional relationship between sleep complaints and pain: Analysis of data from a randomized trial (link here)
- Journal Article: Assessing and Managing Sleep Disturbance in Patients with Chronic Pain (link here)
- Journal Article: Does work stress predict insomnia? A prospective study (link here)
- Journal Article: A Systematic Review Assessing Bidirectionality between Sleep Disturbances, Anxiety, and Depression (link here)
- Journal Article: The role of sleep in the regulation of body weight (link here)
- Journal Article: Insufficient Sleep Syndrome: Is it time to classify it as a major noncommunicable disease? (link here)
- Journal Article: Insomnia: prevalence, consequences and effective treatment (link here)
- Journal Article: Treating chronobiological components of chronic insomnia (link here)
- Journal Article: Australasian Sleep Association position statement regarding the use of psychological/behavioral treatments in the management of insomnia in adults (link here)
- Journal Article: Sleep disorder, Mediterranean Diet and learning performance among nursing students: inSOMNIA, a cross-sectional study (link here)
- Journal Article: Mediterranean Diet and Changes in Sleep Duration and Indicators of Sleep Quality in Older Adults (link here)
- Journal Article: Caffeine consumption, insomnia, and sleep duration: Results from a nationally representative sample (link here)
- Book: How to Sleep Well. The science of sleeping smarter, living better and being more productive. Dr Neil Stanley
- Book: Fast Asleep. How to get a really good night’s rest. Dr Michael Mosley
- Book: Sleep Well Every Night. A new approach to getting a good night’s sleep. Glenn Harrold
- Book: The Sleep Coach. Dr Sarah Jane Arnold
- Book: This Book Will Make You Sleep. Dr Jessamy Hibberd and Jo Usmar
- Journal Article: Sleep and emotions: A focus on insomnia (link here)
- Journal Article: The effects of sleep deprivation on emotional empathy (link here)
- Journal Article: The Association of Sleep and Pain: An Update and a Path Forward (link here)
- Journal Article: Sleep and pain (link here)
- Journal Article: Sleep and Pain: Interaction of Two Vital Functions (link here)
- Journal Article: The Effects of Sleep Deprivation on Pain (link here)
- Journal Article: Duration of sleep contributes to next-day pain report in the general population (link here)
- Journal Article: Sleep and pain sensitivity in adults (link here)
- Journal Article: Sleep difficulties, pain and other correlates (link here)
- Journal Article: Do Sleep Disorders Contribute to Pain Sensitivity? (link here)
- Journal Article: The role of sleep in pain and fibromyalgia (link here)
- Journal Article: Negative Mood Mediates the Effect of Poor Sleep on Pain Among Chronic Pain Patients (link here)
- Journal Article: Intraindividual Variability in Daily Sleep and Pain Ratings Among Chronic Pain Patients: Bidirectional Association and the Role of Negative Mood (link here)
- Journal Article: Does Effective Management of Sleep Disorders Improve Pain Symptoms? (link here)
- Journal Article: Total sleep deprivation increases pain sensitivity, impairs conditioned pain modulation and facilitates temporal summation of pain in healthy participants (link here)
- Journal Article: From Lark to Owl: developmental changes in morningness-eveningness from new-borns to early adulthood (link here)
- Journal Article: Circadian system, sleep and endocrinology (link here)
- Journal Article: Cross‐talk between circadian clocks, sleep‐wake cycles, and metabolic networks: Dispelling the darkness (link here)
- Journal Article: Performance and Mood Following Variations in the Length and Timing of Sleep (link here)
- Journal Article: About Sleep’s Role in Memory (link here)
- Journal Article: Interactions between sleep, stress, and metabolism: From physiological to pathological conditions (link here)
- Journal Article: Interactions between sleep habits and self-control (link here)
- Journal Article: Sleep, Self-Regulation, Self-Control and Health (link here)
- Journal Article: Too exhausted to go to bed: Implicit theories about willpower and stress predict bedtime procrastination (link here)
- Journal Article: Changes in cognitive processing following short-term cumulative partial sleep deprivation and recovery oversleeping (link here)
- Journal Article: Sleep duration and risk-taking in adolescents: A systematic review and meta-analysis (link here)
- Journal Article: Sleep and emotions: A focus on insomnia (link here)
- Journal Article: The effects of sleep deprivation on emotional empathy (link here)
- Journal Article: Nocturnal levels of ghrelin and leptin and sleep in chronic insomnia (link here)
- Journal Article: Short Sleep Duration Is Associated with Reduced Leptin, Elevated Ghrelin, and Increased Body Mass Index (link here)
- Journal Article: Metabolic consequences of sleep and sleep loss (link here)
- Journal Article: The Association of Sleep and Pain: An Update and a Path Forward (link here)