It’s safe to say that most of us would love to sleep soundly through the night and feel our best all day long. While gut health may not be the first thing that comes to mind when considering how to get better sleep, the connection between sleep and digestive health is essential to understand for optimal health and well-being. It's well-known that the gut has a direct link to the brain and that bidirectional communication between the gut and brain affects how both systems function. The state of your gut can impact your sleep, emotions, behavior, and even energy levels, while your brain health directly influences the health and function of your gut. To truly optimize your sleep quality, it’s important to ensure you’re optimizing your gut microbiome and digestion.

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Overview of Sleep Quality

Sleep quality is the measure of how well one is sleeping versus only focusing on the total number of hours slept (sleep quantity). There are four primary measurements to take into consideration when assessing sleep quality: 

• Sleep latency, which is how long of a time it takes you to fall asleep
• Sleep waking, or how often you wake up during the night
• Wakefulness, or how long you stay awake if you do wake up during the night
• Sleep efficiency, which is the total percentage of time in bed you actually sleep

Ideally, sleep latency is under 20 minutes, and sleep efficiency is around 85%, with minimal waking, for sleep quality to be at its peak. Most adults generally need between 7 and 9 hours of sleep, with adolescents and the elderly likely needing more.  

Sleep quality also looks at how long one spends in various stages of sleep:

• Stage 1: a type of light sleep only lasting a few minutes described as the transition from wakefulness to sleep
• Stage 2: also considered a light sleep and occurs before entering deep sleep; this stage is where most sleep occurs 
• Stage 3: a deep sleep that occurs primarily in the earlier portion of the night; this phase is needed for relaxation and restoration and is characterized by the slowest brain wave activity
• REM sleep (rapid eye movement): first occurs 90 minutes after falling asleep, characterized by rapid eye movement and an increase in breathing and heart rate; also the stage where dreaming occurs.

For best sleep quality, adults should be getting 1.5-2 hours of deep sleep per night, and another 1.5-2 hours of sleep time should be dedicated to REM sleep (assuming an average of 7-8 hours per night). Additionally, consistency of sleep is important for sleep quality, with some studies suggesting it’s actually more important than the overall quantity of sleep.  

Not getting enough quality sleep has been linked with a high risk of many chronic diseases, such as depression, obesity, heart disease, and Type 2 Diabetes. Some of the common sleep disorders in which this link has been studied include insomnia, narcolepsy, sleep apnea, and restless legs syndrome. 

Digestive Health Fundamentals

Your digestion is an essential process that involves the breakdown of the food you eat and the absorption of the nutrients from that food across the gut lining, where it can be turned into energy to power your metabolism. While the health of your major digestive organs is paramount to this process, the gut microbiome is also an essential component of optimal digestive health as gut bacteria contribute to the production of vitamins, play a role in estrogen metabolism, synthesize amino acids, and contribute to immune balance in the gut. A third major component of digestive health is the integrity of the gut lining, which is the protective barrier between the gut, bloodstream, and the rest of the body. A damaged or porous gut lining can negatively impact digestive health, resulting in inflammation, food sensitivities, increased immune activity, and other symptoms that can contribute to poor gut health.  

Digestive disorders are among some of the most common conditions treated in functional medicine. Acid reflux/GERD, irritable bowel syndrome (IBS), chronic constipation, and liver disease are some examples of these disorders that can contribute not only to gastrointestinal symptoms but to poor sleep quality as well.  

Impact of Poor Sleep on Digestive Health

Poor sleep quality can negatively affect digestive health and worsen gastrointestinal symptoms. This impact is likely due in part to the bidirectional communication that happens between the brain and the gut. Additionally, it’s been found that sleep deprivation can lead to changes in the ecosystem of the gut microbiome, which may also negatively impact digestive health. 

Much as the circadian rhythm governs our energy levels and sleep/wake patterns, it also impacts the regular rhythm of gut motility, with the gut being more active during the day and less so at night. However, with changes in sleep or sleep disruption, the rhythm of gut motility may change as well - leading to the gut being less active during the day and more active at night, which can result in symptoms like constipation, bloating, trouble falling asleep, or frequently waking up in the middle of the night.

Chronic stress and poor sleep habits have also been found to be associated with higher rates of self-reported IBS and a decreased sense of well-being, further underlying the impact of poor sleep on gastrointestinal health. 

How Digestive Health Affects Sleep

It’s been well-studied that the gut microbiome not only impacts digestion, metabolism, and immune health but also influences mood and sleep quality through the gut-brain axis. It’s possible that microbiotics can influence the expression of genes related to circadian rhythm as well. Chronic stress, as well as inflammation in the gut, has been linked to sleep loss, changes in circadian rhythm, and even affective disorders, bringing to light the close connection between digestive health and sleep quality.  

Gastrointestinal conditions that most frequently impact sleep include acid reflux/GERD, inflammatory disorders such as IBS and IBD, liver disease, and obesity. For example, acid reflux or gastroesophageal reflux disease (GERD) has been linked to shorter sleep duration, increased sleep latency, and frequent wake-ups during the night. The poor sleep quality, in turn, makes it difficult for the body to repair and restore and likely contributes to slower healing. In those dealing with IBS, sleep disturbances are much more common than in the general population and correlate with the severity of gastrointestinal symptoms experienced. Roughly half of IBS patients report some sort of sleep difficulty, whether it be insomnia, frequent wake-ups, or trouble falling asleep. 

Functional Medicine Lab Testing

Functional medicine lab testing can help identify any gastrointestinal imbalances or other relevant issues that may be contributing to poor sleep and digestive symptoms.  

Comprehensive digestive stool analysis, such as the GI-MAP test from Diagnostic Solutions, can provide insight into the health of the gut microbiome as well as assess for the presence of inflammation in the gut. Additionally, this test can look at the functionality of the digestive process to ensure an individual is able to digest and break down their food adequately. The results of the GI-MAP can help personalize a treatment approach that supports optimal digestive capacity, rebalances the gut microbiome, and reduces any inflammation.

Food sensitivity testing, such as the 184 IgA Food Sensitivity Panel by Alletess Medical Laboratory, can be beneficial for those dealing with digestive symptoms, as problematic foods may need to be temporarily removed from the diet in order to reduce inflammation and build back the integrity of the gut. Left unchecked, the inflammation and immune response that can occur to different foods when gut integrity is not ideal can lead to ongoing digestive symptoms, which may impact sleep quality over time.

Hormone testing that evaluates the circadian rhythm may also be helpful in those suffering from poor sleep and digestive symptoms. The Sleep and Stress Panel by Ayumetrix looks at 24-hour cortisol levels and melatonin to better understand hormonal patterns over time. Understanding levels of hormones can help identify if dysregulation of the circadian rhythm is at the root of a patient's symptoms and can help personalize lifestyle recommendations to correct it. 

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Strategies for Improving Sleep and Digestive Health

Improving both the quality of your sleep and of your gut doesn’t have to be complicated. Through simple dietary changes, stress management techniques, and following sleep hygiene practices, you can optimize your sleep quality and help support your gut health. 

When it comes to sleep hygiene, having a consistent sleep and wake time is important for optimal sleep quality, and it helps to have a regular winding-down routine before bed to help calm the mind and prepare for sleep. Going to sleep in a dark, cool bedroom without technology is also ideal for optimizing sleep quality. Practices like deep breathing or meditation can contribute to reduced stress levels, especially if you struggle with “turning off your mind” before bed.

Avoiding caffeine late in the day and avoiding alcohol are important practices to help support better sleep, as both can be disruptive to sleep quality. Ideally, having one’s last meal 2-3 hours before bed and avoiding late-night snacking also ensure the gut has time to digest the last meal before bedtime.  

Supplements such as prebiotics and probiotics can also be helpful for sleep quality. Not only do probiotics support the gut microbiome, but they also help with the synthesis of neurotransmitters and hormones (like serotonin and melatonin) that are important for consistent sleep. Probiotics have been linked to better sleep and mental health with consistent consumption as well. Additionally, prebiotics have been found to improve non-REM sleep, contributing to better sleep quality over time.  

The Role of Diet and Lifestyle

Maintaining a balanced diet and supporting a healthy gut microbiome can contribute to better sleep quality and digestive health. Eating various whole foods, such as fruits, vegetables, and in some cases, whole grains and legumes, can support a healthy microbiome by providing prebiotic fibers to nourish your gut bacteria, while fermented foods like kimchi or sauerkraut can bring more probiotics into your gut microbiome. Generally, a Mediterranean-type diet has been linked to more microbial diversity and overall gut health and can positively influence your sleep quality with adherence.  

Additionally, a lifestyle that emphasizes regular exercise and reducing stress can help support better sleep and gut health. Exercise has been linked to better gut health as well as improved sleep quality, helping active individuals have an easier time falling asleep than those who skip exercise. Chronic stress has been linked to poor sleep, and reducing stress through things like movement, yoga, breathwork, meditation, or play can help support more optimal sleep over time.  

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Gut Health and Sleep: Key Takeaways

Your gut microbiome and digestive health are closely linked to sleep quality through the brain-gut axis connection. Research shows that dysbiosis in the gut microbiome impacts sleep and that the gut microbiome also plays an important role in synthesizing neurotransmitters and hormones related to sleep quality. Functional medicine lab testing can help identify imbalances in the gut microbiome, neurotransmitters, and hormones related to sleep and can help personalize an approach to obtain not only better digestive health but better sleep as well. Through nutrition and lifestyle changes, as well as paying attention to sleep hygiene, it’s possible to improve both digestive health and sleep quality.