Having 2 and 4-year-old kids has me thinking a lot about sleep lately. I’ve been interested in how sleep loss affects the healing process though for a long time since I became fascinated with chronic pain conditions early on in my career. There’s research going back to before I was born linking sleep deprivation and what we know today as fribromyalgia.1,2 Since then, there has been an incredible amount of research linking sleep deprivation with a myriad of health issues. At the end of this article, I break down each of the many aspects of health that are affected by sleep and some of the research that has been done on each topic. Many of the references are mentioned in the fascinating book Why We Sleep by Matthew Walker while many are additional articles I found through my review of the current literature. This post is a greatly expanded version of the information I wrote about in Beyond Tape.
The potential causes of sleep loss are vast but seem to be able to be broken down into 2 categories , behavioral and medical, which can be linked in many cases. Medical causes including obstructive sleep apnea, hormone imbalances, medication-related, and psychological disorders, which should be ruled out first by a qualified health care professional.3,6,9 Behavioral causes can be changed by modifying a person’s behavior, such as avoiding screens before bedtime. Oftentimes, the causes are more on the behavioral end, which is where treatments like cognitive behavioral training and sleep hygiene techniques come into play. Cognitive behavioral training (CBT), when performed by an expert in this field, has been found to be the most effective (even more so than sleep medications in some studies). Sleep hygiene tips, one aspect of CBT, have been shown to be helpful as well.4-11 Check out my evidenced-based handout for sleep hygiene tips if you or someone you know suffers from sleep problems.
As a physical therapist, I’m mostly fascinated with the effects of sleep on injuries and the healing process. Growth hormone is produced during stage 3, a deeper stage which is considered slow-wave non REM sleep, of the sleep cycle.12-14 This hormone helps to facilitate the healing process. It takes roughly 90 minutes to get into this stage of the sleep cycle.15 Inadequate sleep has been shown to decrease growth hormone production. Sleep disturbance can also contribute to myofascial trigger point formation, another contributor to chronic pain. Psychological stress is a major cause of sleep loss. This is a double-whammy, as stress causes an increase in production of the hormone cortisol (as does sleep deprivation), which has a negative impact on healing. Laughter, meditation, and yogic breathing each have been shown to decrease the negative effects of stress.13,14
Aside from the affects on the healing process, sleep loss is linked to all kinds of problems which are described in the summary below. Some big ones that are being talked about in the research are the link with metabolic syndrome (increased blood pressure, high blood sugar, excess body fat around the waist, and abnormal cholesterol or triglyceride levels — that occur together, increasing your risk of heart disease, stroke and diabetes), obesity and type 2 diabetes, both in adults and kids.16 This is thought to be due to the effects on hormones that play a major role in control of appetite and energy expenditure. Hunger increases with poor sleep.
Here is a summary of the health issues associated with poor sleep quality and quantity:
- Cancer – Night shift work is associated with breast, prostate, and endometrial Cancers.17-19
- Cognitive impairments – Cognitive functioning has been found to be impaired in all age groups, from children to the elderly, when restricting sleep by as little as 1 hour over 5 nights or 1 night of sleep deprivation.20-22
- Alzheimer’s – Sleep fragmentation (repetitive short interruptions of sleep) and insomnia are found to be associated with Alzheimer’s and an increased rate of cognitive decline.23,24 Treating obstructive sleep apnea has been shown to improve cognitive function in Alzheimer’s patients.25
- Cardiovascular disease and blood pressure – Poor sleep quality and insomnia are associated with increased blood pressure and vascular inflammation (C-reactive protein, a stable marker of inflammation that has been shown to be predictive of cardiovascular morbidity, has been shown to be elevated in subjects with total and partial sleep deprivation).26,27 People who get more sleep have been shown to have lower coronary artery (blood supply to the heart) calcification incidence.28 All these problems increase the risk of heart attacks and strokes.
- Common cold and upper respiratory illness – Sleeping for less than 7 hours of sleep per night has been shown to be associated with an increased incidence of developing the common cold.29-31
- Chronic pain and fibromyalgia – Sleep deprivation, especially of stage 3 in non REM sleep, has been shown to produce fibromyalgia-like symptoms of muscle tenderness and central sensitization. This is where the nervous system becomes overly reactive, requiring less and less of a stimulus to create the sensation of pain and the pain is maintained even after the initial injury has healed.32-34 And as I mentioned above, stage 3 is when growth hormone is released which helps to facilitate the healing process. Sleep hygiene education has been shown to decrease pain and fatigue in patients with fibromyalgia.35 Sleeping less than 6 hours has been associated with increased cortisol release and increased sympathetic nervous system activity, which contribute to central sensitization.36 Sleep disturbance is also thought to be a factor in the perpetuation of myofascial trigger points.37
- Low back pain – Improvements in sleep quality are associated with improvements in low back pain and disability. 38
- Obesity – Sleep deprivation in both the short and long term is associated with increased obesity, body mass index, and weight gain in adults and children (including infants). This is due to several factors including decreased glucose tolerance and carbohydrate metabolism, decreased insulin sensitivity, increased evening concentrations of cortisol, increased levels of ghrelin, decreased levels of leptin and increased hunger and appetite. Ghrelin and leptin sound like Lord of the Rings’ characters, but they’re actually crucial hormones for regulating appetite. Grehlin is an appetite stimulant and leptin an appetite suppressant.39-45
- Type 2 Diabetes – Sleep deprivation and poor sleep quality are associated with an increased prevalence of type 2 diabetes. This is due to decreased carbohydrate metabolism and glucose tolerance, leading to insulin resistance and diabetes.46-49
- Sports injuries and performance – Decreased sleep is associated with a significantly increased prevalence of injury. In one study, the likelihood of having an injury was 75% for 6 hours of sleep versus 18% for 9 hours in high school kids and 65% of kids were injured who slept less than 8 hours versus 31% who slept longer than 8 hours. This is thought to be due to the findings in other studies showing an association between sleep loss and impairment of psychomotor performance, motor function, mood, and cognitive functions.50 Exciting research regarding performance shows that basketball players who increased their sleep to at least 10 hours sprinted faster, shot more accurately, and noted improved physical and mental well-being.51 Decreased sleep is also associated with decreased performance, especially with “sports-speciﬁc skill execution and submaximal sustained exercise bouts”. Increasing sleep showed an increase in “sports-speciﬁc skill execution and cognitive related tasks, such as reaction time and shooting accuracy”.52
- Bone loss – Bone loss has been shown to occur after 3 weeks of sleep disruption, due to bone formation being decreased while bone resorption stays the same.53
- Sleep medications – As a physical therapist, its beyond my scope of practice to give recommendations on medications. That being said, sleep medications such as Restoril and Ambien have been shown to significantly reduce slow wave activity during non REM sleep. Again, this is also called deep sleep and is the phase when growth hormone is released for healing of damaged tissues, glial cells in the brain are restored with sugar to provide energy for the brain, and synapses in the brain which are formed from learning and memory during wakefulness are regulated.54 Other factors that you may want to consider are that in some studies, sleep medications were no more effective than behavioral treatments55 and sleep medications have common, and often significant, side effects.54,56,57
It may seem strange for your physical therapist to be concerned about your sleep patterns, but I find (as does the research) that addressing all aspects of a person’s health leads to better and longer-lasting outcomes. This is the purpose of my handouts for evidence-based sleep hygiene tips and evidence-based wellness topics. Poor sleep quality and quantity is not just a normal part of the aging process and there are things you can do.
Like my facebook page for updates and more information and rate/review Beyond Tape on my website or here. My primary motivations for Beyond Tape and any of the posts are to: 1. Check out the most relevant and up-to-date research for each topic in order to dispel myths, sift out conflicting views, and help people to prevent or heal from injuries – letting me know about new research or opposing views is helpful and greatly appreciated 2. Contribute to the local and global communities by donating 100% of my net profits from Beyond Tape to service-based non-profit organizations, such as Rotary International, Doctor’s Without Borders, Access Fund, etc.
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33Moldofsky H, Scarisbrick P, et al. Musculosketal symptoms and non-REM sleep disturbance in patients with “fibrositis syndrome” and healthy subjects. Psychosom Med. 1975 Jul-Aug;37(4):341-51.
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