Rest, Recharge, Recover: A Deep Dive into Sleep & Mental Health

When was the last time you had restorative sleep? While some of us might feel that restorative sleep is a luxury, we’re here to tell you that it’s absolutely a necessity, especially for your mental health. Let’s unknot the relationship between sleep and mental health. Mental health is impacted by various body systems, with sleep being an overlooked piece to these interconnected systems. Research has demonstrated a bidirectional relationship between sleep and mental health. 

A recent meta-analysis and systematic review revealed insomnia is a significant predictor for the onset of depression and anxiety, among other mental health conditions. A previous review showed that 70-90% of patients with PTSD also have sleep difficulty. 

Sleep plays an important role in fostering mental health through a variety of pathways. Disrupted sleep has been shown to induce changes in neural, metabolic, hormonal and immune processes— all of which have important roles in mental health. 

Compromised sleep can disrupt hormonal balance– including healthy levels of testosterone, estrogen and progesterone– significant for mood health. This is because poor sleep results in hypothalamic–pituitary–adrenal (HPA) axis activation, leading to an increase in stress hormones, while causing an imbalance in these modulatory hormones. 

Many hormones that are related to metabolism are regulated by sleep and circadian rhythm. Sleep disturbance is associated with impaired glucose and lipid metabolism, cortisol and expression of clock genes, necessary for governing the body’s circadian rhythm. 

Alterations in these systems can further impact sleep and mental health, via systemic and neuroinflammation, impeded immunity and altered metabolic homeostasis, further demonstrating their unique relationships.

Sleep also helps to promote activation of the lymphatic and glymphatic systems— essential for clearing cerebral waste from the body and brain. These processes support the central nervous system (CNS) and immune system in modulating mental health, and are governed by sufficient sleep. 

Additionally, there is a relationship between sleep, gut and mood. Immune and hormonal functions are altered by imbalances in the microbiome, lack of sleep and chronic stress. Psychoneuroimmunology (PNI) describes the impact stress has on impeding these processes. Dysregulation in the immune system is often a hallmark of sleep deprivation.

The microbiota–gut-brain axis describes the bidirectional communication between the nervous system and the gut, facilitated by the vagus nerve. This nerve is able to sense information relative to the microbiome, and relay this to the central nervous system, and vice versa; serving as a two-way highway between the body and mind. This connection highlights how the microbiome influences mood, and how stress impacts the microbiome, with poor sleep exacerbating these effects.

Beneficial gut microbiota influence mood by secreting neurotransmitters and neuromodulators– including GABA, serotonin and dopamine—integral for modulating the nervous system. Gut microbiota also secrete amino acids that can be further converted into neurotransmitters, while also having roles in producing enzymes that influence activity of hormone and immune cell functions. 

Metabolites produced by gut microbiota—such as short-chain fatty acids (SCFA) and bile acids—also serve regulatory functions for mood. These metabolites modulate gut microbiome composition, inflammation, immune response, hormonal balance, metabolism, and compellingly circadian rhythm. 

The gut also represents a large portion of the lymphatic system, further underscoring its role in promoting well-being. 

How to Improve Sleep & Mental Health

Simple lifestyle tweaks can improve quality of sleep, which in turn, supports good mental health. Epigenetics, the influence of gene expression associated with lifestyle factors, is a growing body of research that underscores these connections. Remarkably, the gut microbiome offers vast opportunity to favorably influence gene expression, encoding an estimated five million genes. 

Lifestyle factors, including nutrition, stress reduction, circadian rhythm balance, and proper sleep hygiene— support regulation of the gut microbiome and sleep, and thereby homeostatic functions related to mental health. 

Nutrition

Increasing microbial diversity with an abundance in plants is important for promoting healthy sleep, as well as following an anti-inflammatory, nutrient dense balanced diet. Sufficient amounts of macronutrients, including quality proteins, minimally processed, complex carbohydrates, healthy anti-inflammatory fats, and water all support sleep. 

Ensuring sufficient amounts of probiotics (yogurt, miso, kimchi) and prebiotics (bananas, spinach, artichokes) are also important for sleep modulation, as these have been shown to produce and regulate metabolites that play key roles in sleep-including neurotransmitters and hormones. Research demonstrates that microbiome diversity is associated with improved sleep and mental health. Microbes associated with increased microbial diversity have been shown to produce GABA for instance, significant for modulating stress, arousal and supporting the body’s ability to sleep. Whereas pathogenic microbiota and inflammatory markers have been associated with poor quality sleep and mental health.

Micronutrients— notably vitamins A, D, E, and B— all play roles in promoting healthy sleep. Vitamin A (carrots, sweet potatoes) remarkably supports circadian rhythm. Vitamin D receptors have been found in the brain regions involved in sleep regulation. Vitamin D (salmon, egg yolks) is also shown to be involved in modulating sleep-wake cycles, with deficits associated with sleep disorders. Vitamin D is also imperative for mental health by supporting immunity and healthy levels of inflammation. Whereas sufficient levels of vitamin E (nuts and seeds) are important for antioxidant functions, combating oxidative stress and inflammation. B vitamins (poultry, mushrooms and leafy greens) support neurotransmitter synthesis, among other functions for supporting sleep. 

Minerals, including magnesium, zinc, calcium, selenium and iron are further essential for healthy sleep. Magnesium (legumes, leafy greens) supports sleep due its modulating effects on neurotransmitters and hormones. It also regulates melatonin production, in addition to a host of biochemical reactions. Zinc is associated with improved sleep, as it promotes gut microbiome, hormonal and neurotransmitter modulation. Selenium is also noteworthy for sleep due to its antioxidant properties, supporting the brain and body. Iron (seafood, dark leafy greens, nuts and seeds) is involved in synthesis of dopamine and serotonin. 

Berries and pineapple are further supportive nutrient dense foods, given their polyphenol content and natural digestive enzymes—further helping to mitigate inflammation and oxidative stress—as well as modulate the microbiome 

Stress Reduction 

Combating hyperarousal is also significant for managing anxiety and is integral to improved sleep, mental health and performance. Yoga nidra and grounding techniques, including using a weighted blanket, essential oils, mindfulness-meditation, deep breathing and progressive muscle relaxation (PMR) are further strategies to support sleep, stress and mental health. Bringing gentle awareness to your body throughout the day and attuning to its needs, may be further supportive for overall sleep and mental health. For instance, recognizing your need to slow down and nourish your body, or the need for movement. The practice of yoga can be modified depending on our dynamic needs, and used to help the body and mind unwind, while promoting the lymphatic system. 

Psychotherapy for Insomnia 

Stress reduction is imperative for combatting poor sleep. Breaking the sleep-stress cycle by utilizing strategies, such as Cognitive Behavioral Therapy for Insomnia (CBT-I) may be helpful for improving sleep and mental health. Core components of this approach include identifying dysfunctional thoughts relative to sleep that perpetuate the poor sleep cycle, examining these thoughts for accuracy and modifying them as appropriate. For instance, “I can let go and trust in my body’s natural ability to sleep.” 

Supporting Circadian Rhythm

Circadian rhythm balance is also significant for improving sleep and mental health. Getting exposure to sunlight in the morning, along with maintaining a regular sleep-wake cycle that aligns with the sun, are all ways to promote circadian rhythm balance— which influences metabolic, immune and mood— having further implications for mental health. 

Research shows that dysfunctions in circadian rhythm are observed in those with mental health conditions, as evidenced in a recent review. Impeded circadian rhythm was reported in individuals with anxiety, MDD, bipolar and other mental health conditions. 

Appropriate light exposure, red light therapy and regular exercise, along with structured routines and meal timings can support sleep and mental health. It is also important to refrain from artificial light and screen time at night, as these can further compromise circadian rhythm. Disruptions in circadian rhythm have been demonstrated to impede sleep-wake cycles and neurotransmitter and hormone levels. Alterations in gut microbiota have also been shown in those with disrupted circadian rhythm. 

Lifestyle Tweaks

Establish a bedtime and wind-down routine.  Aim to set and stick to a bedtime that allows you to get at least 7-8 hours of sleep. Ensure your sleep environment is dark and cool. Be mindful of your caffeine and alcohol consumption, as these can greatly disrupt sleep. Strive for at least 15-20 minutes of sunlight in the morning and regular exercise or movement to support circadian rhythm balance. 

Sleep has a foundational role in governing homeostatic functions in the body and mind, notably via the gut microbiome. This is encouraging, as we can work towards improving sleep and these interconnected processes, with factors in our control to support mental health.