In recent years, studies have shown that changes in the gut microbiome (the trillions of microorganisms that live in the gut) may influence the risk for chronic health conditions. Physical inactivity is another factor that may contribute to health risk, with research indicating an association between inactivity and the development of various chronic diseases.
Exercise is known to be a healthy lifestyle practice, along with a balanced diet, that supports overall health and well-being, potentially reducing the risk of chronic disease. One way exercise might benefit our health is through its impact on the gut microbiome.
With many Americans experiencing gastrointestinal disorders, gut health has become a focus of attention. In this article, we'll explore how exercise may impact the gut microbiome and overall gut health.
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What is a Healthy Gut?
From the mouth to the bowel, gut health covers the well-being of the entire gastrointestinal system. This system's health largely depends upon the gut microbiome or the trillions of microorganisms that reside there.
Your gut is responsible for the digestion of food, absorption of nutrients, and various vitamins and nutrients produced by the gut microbiome. The gut contains 70-80% of the body's immune cells, it offers a mode of elimination of toxins and waste products, it communicates with and modulates aspects of the nervous system, and it has a very significant impact on our overall health.
From a Functional Medicine perspective, a healthy gut doesn't just mean the absence of disease. It means optimal structure and function. In this light, a healthy gut would include an intact mucus barrier and intestinal lining, normal immune and neurologic responses, normal digestive and absorptive processes, normal elimination, low inflammation, and a healthy microbiome.
A healthy microbiome includes diversity (a plethora of different types of beneficial strains of microorganisms) and consists of a higher abundance of these beneficial strains of microorganisms and less of the pathogenic strains of microorganisms. A healthy microbiome also shows signs of resistance and resilience. Resistance includes the ability to resist disruption by pathogenic strains of microorganisms, and resilience is the ability to return to a healthy state after experiencing disruption.
The microbiome is considered a key element not only regarding gut health but in regulating our overall health. So, taking actions that lead to a healthy gut may also have a positive impact on overall health.
Dysbiosis Signs & Symptoms
Dysbiosis is the term for a disruption in the microbiome. This occurs when an imbalance exists between the gut's beneficial and pathogenic (harmful) microorganisms.
Characteristics of dysbiosis include a decrease in the abundance of beneficial microbes, overgrowth of pathogenic microbes, and decreased microbiome diversity. Dysbiosis is also associated with increased gut lining permeability, often called "leaky gut." This increase in intestinal permeability may produce an inflammatory response as microbes enter into circulation. Dysbiosis can lead to many signs and symptoms.
Gastrointestinal symptoms may include:
- Gas
- Cramping
- Bloating
- Diarrhea
- Constipation
- Belching
- Bad breath (halitosis)
- Nausea
- Acid reflux
- Vomiting
- Abdominal pain
- Food allergies or sensitivities
- Mucus in the stool
Dysbiosis can also produce symptoms outside of the gastrointestinal tract. Some people experience symptoms like:
- Joint pain and inflammation
- Chronic fatigue
- Brain fog
- ADHD or difficulty concentrating
- Anxiety
- Depression
- Acne
- Eczema
- Psoriasis
How Does Exercise Support Gut Health?
The big question is, how does exercise support gut health? The short answer is that exercise may benefit gut health by increasing good bacteria, potentially improving microbiome diversity, reducing inflammation, supporting the integrity of the gut lining, and enhancing gut function. We'll dive into the evidence below.
Microbiome Diversity & Abundance
Exercise may increase the abundance of beneficial strains of bacteria in the gut. Studies have shown that women who exercised 3 hours per week had higher levels of health-promoting bacterial species, including Faecalibacterium prausnitzii, Roseburia hominis, and Akkermansia muciniphila. Two of these bacterial species (F. prausnitzii and R. hominis) are known to produce a short-chain fatty acid (SCFA) called butyrate. Butyrate is the primary source of fuel for the cells in the colon and may have anti-inflammatory actions in the gut. A. muciniphila is a beneficial strain of bacteria that resides in the mucus layer of the gut and has been shown to positively impact metabolism, regulate immune function, and protect gut health.
This increase in beneficial strains of bacteria that may result from moderate exercise represents an increase in microbiome diversity. This finding is supported by studies that found microbiome diversity to be higher in athletes than in sedentary individuals.
Inflammation & Bowel Function
Exercise may reduce both systemic and intestinal inflammatory markers, potentially reducing inflammation not just in the gut but throughout the entire body. Exercise also supports bowel function by improving colon transit time in women.
What Type of Exercise Supports Gut Health
Aerobic exercise is shown to increase the diversity and abundance of Firmcutes and Actinobacteria phyla, which contains the Lactobacillus and Bifidobacterium genera of bacteria, respectively, known to be vital to gut health.
A moderate amount and intensity of exercise, such as 3 hours per week, appears to provide the best results for gut health. As the intensity of exercise increases, the prevalence of gastrointestinal symptoms also increases, and exercise training to exhaustion is even associated with dysbiosis.
High-intensity exercise is associated with increased levels of stress hormones, such as cortisol, and a transient increase in gut permeability. This may explain the increase in gastrointestinal symptoms associated with higher-intensity bouts of exercise.
It should be noted, however, that individuals who exercise regularly (trained athletes) are shown to have lower levels of circulating bacterial endotoxin lipopolysaccharide, an inflammatory marker associated with increased gut permeability. This indicates that, when performed regularly, exercise acts as a beneficial stressor on the gut, which may trigger beneficial adaptations that support the long-term resilience of the integrity of the gut lining.
Research shows that when exercise is discontinued, changes in the microbiome may revert back to baseline, indicating that exercise would need to be maintained as a lifestyle habit in order to have continued benefits for gut health.
How to Test Your Gut Health
Your Functional Medicine practitioner may order functional lab tests to understand the health of your gut microbiome and your overall gut health.
Comprehensive Stool Analysis
Comprehensive stool analysis testing provides an in-depth overview of the structure and function of the gastrointestinal system by providing information about digestion and absorption, inflammation, and microbiome analysis. The GI-MAP + Zonulin test by Diagnostic Solutions and the GI Effects® Comprehensive Profile from Genova Diagnostics both offer comprehensive stool analysis.
This article compares the top 4 comprehensive stool analysis tests to evaluate the gut microbiome and overall gut health.
Intestinal Permeability Testing
Testing for an increase in a protein called zonulin indicates whether there is an increase in the permeability of the gut lining. This increase in permeability of the gut lining is often referred to as "leaky gut." Zonulin can be measured in a comprehensive stool test or evaluated with a blood test. The Advanced Intestinal Barrier Assessment, or Advanced IBA, is a blood test that measures several markers associated with intestinal permeability, including zonulin.
SIBO Breath Test
A breath test may be ordered when disruption in the microbiome is suspected further up in the GI tract, in the small intestine. This test evaluates for small intestine bacterial overgrowth (SIBO). It is performed by drinking a sugar solution and measuring methane and hydrogen levels in the breath, collected in tubes at specified timing.
Summary
Regular physical exercise isn't only an excellent lifestyle practice for supporting overall health and potentially reducing risk for chronic disease. Exercise offers an exciting, attainable option for supporting the gut microbiome and overall gut health.
Regular, moderate physical exercise may support beneficial changes in gut health by potentially improving microbiome diversity, increasing the abundance of beneficial microbes, reducing inflammation, improving gut function, and even supporting the resilience of the integrity of the gut lining.
If you're looking for a way to support your gut health, talk to your healthcare practitioner about how you can make moderate physical activity part of your lifestyle!
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