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Exercise & Gut Microbiome

The relationship between the gut microbiome and exercise has become a subject of exploration. Recent research has shed light on the ecosystem within our guts consisting of bacteria, archaea, eukaryotes and viruses that have evolved alongside humans for thousands of years. This community, known as the gut microbiota, plays a role in digestion, metabolism and immune system strength.


The sheer biological potential residing in our gut microbiota is truly remarkable. With more than 1,000 bacterial species and an astonishing 3 million unique genes this collection of genetic material is referred to as the gut microbiome.


These tiny companions that live in harmony with us have the ability to metabolize what we eat and respond to our stress levels.. Now emerging research is uncovering the impact that physical exercise has on the composition and functions of these microorganisms in our guts.


Before diving into the connection between exercise and the gut microbiome let's briefly touch upon some basics about the microbiome. Your gut is home to a range of microorganisms including yeasts and other microscopic organisms. Among their roles they break down food molecules into nutrients that support health.

These tiny organisms produce substances, like fatty acids, vitamins and amino acids which provide benefits to our body. These benefits range from strengthening our system to protecting and maintaining a gut lining [1].


The Connection Between Gut Microbiome and Physical Activity


Leading a lifestyle creates a beneficial relationship with the microorganisms in our gut. We provide them with a home. They work alongside us.


Having a microbiota profile is associated with increased production of vitamins, breakdown of fiber generation of short chain fatty acids and improved defense against diseases.


The microbiome has an impact on nutrition, metabolic health, immune responses and intriguingly even influences the brain.


It's not far-fetched to consider that exercise plays a role in shaping the microbiome. Having species is an essential indicator of microbiome health since this ecosystem consists of hundreds of different species.


On the other hand dysbiosis refers to a malfunctioning ecosystem that struggles to perform its functions properly. This can potentially lead to problems and various conditions.

The impact of gut health on muscle growth and recovery is a topic that has gained consensus. The relationship between the gut microbiota and the host is considered beneficial with shared biological needs.


While there have been studies exploring how the gut microbiota affects liver and intestinal metabolism, immunity and behavior, fewer have focused on its role in regulating muscle. A crucial metabolic organ.


Recent research has shed light on how the gut microbiota influences skeletal muscle mass and function in mice. It was observed that mice without any microorganisms (known as germ mice) had reduced muscle mass signs of muscle atrophy and weakened strength.


This situation in germ mice showed an imbalance where protein breakdown exceeded protein synthesis. This could potentially contribute to the decrease in skeletal muscle mass [4].


Gut microbes play a role in synthesizing acids that are then made available to the host [5].


Further analysis of metabolites in muscle, liver and serum revealed changes in amino acid metabolism, among germ mice. Specifically there were concentrations of leucine and valine. Both are associated with branched chain amino acid (BCAA) catabolism linked to skeletal muscle protein breakdown. Observed in liver tissue and serum.


BCAAs, which serve as a source of energy play a role in enhancing nitrogen retention and protein synthesis. They are particularly important for the production of alanine in muscle tissues.


Before being converted into fuel and entering the acid cycle BCAAs undergo transamination leading to the production of alanine. In mice without gut microbiota there is an increase in alanine levels in muscles due to higher breakdown of muscle proteins. This increase helps provide acids to cope with the stress caused by the absence of gut microbiota.


Short chain fatty acids produced from fermentation of polysaccharides have been found to have numerous interactions between the host and gut microbiota. These short chain fatty acids are believed to support muscle function by preventing atrophy and improving strength.


However it is not just short chain fatty acids that contribute to muscle growth and function. The gut microbiota's biosynthetic activities go beyond providing energy for the host suggesting that other microbial products also play a role in regulating muscle growth and function [5].


Further research is needed to identify metabolites or microbial products produced by bacteria that influence skeletal muscle growth and function. In summary this research has revealed a connection between the gut microbiota and skeletal muscles opening up avenues for investigations into understanding how this crucial metabolic organ functions.


The Influence of Exercise, on the Gut Microbiome

Hands, Woman in Park and Stomach Fitness

 research highlights the way exercise affects the bacteria in our gut. Various studies conducted on animals have shown that exercise training independently modifies the composition and functional abilities of the gut bacteria [7].


Early investigations discovered that exercise training increases the presence of butyrate, a byproduct produced by bacteria. This finding has been confirmed by studies. Butyrate, which is derived from fermenting fiber by bacteria, plays a role as the main energy source for cells lining our intestines. It helps maintain integrity, reduces inflammation, prevents substances from entering our bloodstream and even aids in regulating our immune system [8].


Studies conducted on humans over a period of time have revealed changes in their gut microbiota due to exercise. The changes observed varied depending on their body mass index (BMI). Interestingly exercise increased the abundance of types of bacteria that produce butyrate and led to concentrations of acetate and butyrate in their feces especially among those with a lean BMI. What's intriguing is that many bacterial types and short chain fatty acids that saw an increase during exercise subsequently decreased during a period lasting six weeks. These findings indicate that exercise's effect on the gut microbiota is temporary and reversible [8].


In addition to these findings another study investigated whether endurance exercises could affect the makeup of gut bacteria, in women who were previously inactive. After engaging in moderate intensity cycling, for a period of six weeks there was an increase in the presence of A. Muciniphila bacteria and a decrease in Proteobacteria which are prominent Gram negative bacteria.


These findings collectively suggest that exercise has effects on the composition of the gut microbiota. It is possible that prolonged or intensive aerobic training may be necessary to bring about changes in taxonomic and metagenomic profiles. Additionally it appears that individuals who are lean may show responsiveness to exercise compared to those who're overweight or obese [8].


The Complex Interplay Between Gut Health and Mental Well being


The gut microbiota has also been recognized as playing a role in health and cognitive function thanks to the established existence of the gut brain axis [9].


Metabolites produced by the gut microbiota can activate receptors within the system, which is a network of neurons responsible for regulating the gastrointestinal tract. Furthermore certain types of microbes have the ability to synthesize neurotransmitters. For example species like Lactobacillus can produce serotonin and gamma aminobutyric acid (GABA) [10].


Serotonin is known to influence cognitive functions with low levels being associated with depression. GABA serves as the neurotransmitter in the central nervous system and typically has anti anxiety and relaxation effects.


When there is an imbalance or dysbiosis, within the gut microbiota it may contribute to compromised health. People who experience depression often have a changed gut microbiota, which is characterized by shifts, in the levels of Firmicutes, Bacteroidetes and Actinobacteria. Interestingly when fecal matter from these individuals is transferred to rodents that are raised in a germ environment it leads to depressive behavior in those rodents [11].


The positive effects of exercise on neurological well being are well documented. Its possible that some of these benefits are mediated by the gut microbiota. For instance regular exercise has been linked to an increase in the levels of Lachnospiraceae bacteria, which produce butyrate. Interestingly higher levels of Lachnospiraceae bacteria have been associated with reduced anxiety behavior [7].


Studies have shown that butyrate can enhance the expression of brain derived factor (BDNF) in the brains of mice. This protein supports the survival of existing neurons while facilitating the development of neurons and synapses. Additionally butyrate plays a role in regulating cell activation—a group of immune cells found in the brain [12].


Similar to exercise, butyrate seems to promote neuroplasticity and possesses antidepressant qualities by increasing levels in the brain [13].


Promoting Gut Health Through Diet and Exercise

Microbiome intestine factories and microbiota. Gut health 3d

Tips, for Improving Diet


The impact that our dietary choices have on gut microbiota composition is undeniable. Consuming diets high in sugars and fats while lacking fiber has been linked to a decrease in the diversity of our gut bacteria leading to a loss of microbes and an imbalance in the gut ecosystem.


On the hand , incorporating high fiber foods like fruits, vegetables, legumes and whole grains into our diet can promote a range of microbial diversity.


Different dietary factors can disrupt the balance between harmful bacteria in our gut, which may result in inflammation, gut imbalances and various health issues such as conditions, allergies, colorectal cancer and metabolic disorders.


For health benefits it is advisable to consume foods that are rich in fiber and include fruits, vegetables, legumes and whole grain carbohydrates.


The Role of Probiotics


Probiotics are microorganisms that have been extensively studied due to their health benefits when introduced into our gut microbiota. They can influence the composition of our gut bacteria to impact protein metabolism related to diet choices. Affect enzyme activity. Additionally probiotics may physically attach themselves to the lining which might help harmful pathogens while inhibiting their activation. Furthermore probiotics have shown potential in improving permeability.


The use of probiotics has been investigated for health effects, among athletes including modulation as well as strengthening the protective barrier of their intestinal lining.

Probiotics have been linked to improvements in inflammatory markers. Their impact on athletic performance is still uncertain. New research suggests that next generation probiotics found in the microbiomes of athletes during exercise could potentially enhance endurance capacity [21].


Exercise Tips


Several studies have revealed a connection between the composition of gut bacteria and cardiorespiratory fitness accounting for more than 20% of the variability in diversity within the microbiome.


Cardiovascular exercise involves activity that raises and maintains heart rate ensuring an adequate supply of oxygen to muscles for ATP production. Following the exercise guidelines provided by the World Health Organization can contribute to a healthier gut microbiome;


Engage in intense aerobic physical activity for at least 150–300 minutes.

Alternatively participate in intense physical activity for at least 75–150 minutes or a combination of moderate and vigorous activities spread throughout the week [23].


In Conclusion


Our understanding of the relationship between exercise and the gut microbiome continues to evolve. A crucial area for research involves examining how changes in gut bacteria induced by exercise affect skeletal muscle parameters such as structure, mass, strength, function and metabolism. These factors ultimately influence skeletal muscle health and performance. Compounds derived from diet and modified by the microbes in our gut have the ability to enter our bloodstream and impact the cells in our muscles. Some of these substances include short chain fatty acids, amino acids, secondary bile acids, polyphenols and vitamins. Over the years both animal and human studies have emphasized the positive role that exercise plays in shaping a healthy gut microbiota. This connection between exercise and the microbiome has the potential to contribute to improved health and physical performance. While there is still more to discover about how exercise influences our gut bacteria, the knowledge gained far promises to provide us with a deeper understanding of the intricate mechanisms that govern this essential metabolic partnership.


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Kayla Thomas


Kayla Thomas, a 34-year-old sports and fitness coach living in Connecticut, USA. With seven years of hands-on experience, she's all about helping folks get fit and strong. Kayla's fitness journey began when she was a sports-loving kid, and she followed her passion to college, where she earned a degree in Exercise Science and picked up personal training and sports coaching certifications. But what really lights her up is empowering women through fitness, breaking barriers and making fitness feel welcoming for everyone. Her clients see her as not just a coach but a motivating friend. In her downtime, you'll find her swimming and cycling, always on the move. And you can follow her fitness journey on Instagram – she's all about sharing that empowerment vibe.