Stronger, Faster, Healthier: The Power of Your Gut in Sports

Have you ever wondered how your gut health might be influencing your fitness journey? A well-balanced gut microbiome can be a game-changer not just for overall well-being, but also for optimising training performance, recovery, and even nutrient absorption. Over the years, both ancient wisdom and cutting-edge research have confirmed the critical role your gut plays in your health and athletic performance. 

It’s fascinating to note that the importance of gut health was recognized as far back as 400 B.C., when Hippocrates famously stated, “Death sits in the intestines.” Fast forward to today, and research has revealed that the trillions of microbes living in our intestines—collectively known as the gut microbiome—are essential for more than just digestion. With over 70% of our total immune cells being in the gut they play key roles in regulating your immune system, influencing metabolism, and even impacting muscle function.

How Exercise and Your Microbiome Interact

Recent studies have shown that exercise and your gut microbiome share a symbiotic relationship:

Exercise Improves Gut Health: Moderate exercise, particularly endurance and strength training, can increase the diversity of your gut bacteria. This improved diversity is believed to help enhance nutrient absorption, regulate inflammation, and boost your immune system. High-intensity workouts have been particularly effective at nurturing a healthier gut environment (1).

Gut Health Boosts Training Adaptations: A balanced gut microbiome not only influences overall health but may also play a vital role in muscle growth and recovery. Research involving animal studies has demonstrated that an intact gut microbiome supports muscle cell adaptations and can even influence aerobic capacity and mitochondrial function (2).

However, balance is key. While moderate physical activity strengthens the gut microbiome and prevents intestinal inflammation, overtraining might disrupt it, reducing microbial diversity and even promoting inflammation. Studies in mice have shown that prolonged periods of excessive training, especially when paired with antibiotic use, can result in less muscle gain and a diminished training effect (3).

The Impact of Antibiotics on Training

Antibiotics are essential for fighting infections, but they can also wreak havoc on your gut microbiome. Interestingly, research has shown that athletes tend to use oral antibiotics approximately twice as often as non-athletes, possibly due to exposure to pathogens in crowded training environments or the physical stress of intense exercise. This frequent use of antibiotics may lead to a decline in athletic performance in different ways (4).

Hamper Muscle Adaptation: Studies in mice have shown that antibiotic treatment during training can reduce muscle growth and alter the composition of gut bacteria, ultimately impairing training outcomes.

Reduce Aerobic Capacity: When mice undergoing endurance training were treated with antibiotics, they displayed a smaller increase in aerobic capacity and mitochondrial function compared to untreated mice (5).

Fiber Fuel for Athletes:

While carbohydrate guidelines for athletes are well established, fibre intake - the food for our microbes - lacks specific recommendations despite its role in gastrointestinal comfort, body composition, and overall health. Athletes consuming less than 20 g of fibre daily should gradually increase intake to ~30 g over six weeks to support gut microbiome diversity, intestinal barrier function, and short-chain fatty acid production. However, athletes should avoid fiber intake for a few hours around training or competition to prevent digestive discomfort (6). 

Boosting Performance with Beneficial Bacteria

Exciting research from Harvard has revealed that certain bacteria in the gut may enhance athletic performance. Researchers isolated a bacterium known as Veillonella atypica from marathon runners and found that when introduced to mice, it significantly improved their endurance on treadmill tests. This bacterium appears to convert lactate into propionate—a compound that might boost performance. Although these findings are still emerging and first supplementation studies of Veillonella atypica haven’t shown to be effective in enhancing sport performance in humans, they nonetheless underscore the tremendous potential of personalised gut-targeted strategies (7). 

Ten conclusions made by the International Society of Sports Nutrition (ISSN) for Probiotic supplementation

The position statement by the International Society of Sports Nutrition (ISSN) offers a critical review of probiotic supplementation for athletes and highlights several key conclusions:

1. Probiotics and Health Benefits: Probiotics are live microorganisms that, when administered in adequate amounts, confer a health benefit on the host.

2. Research-Backed Applications: Probiotic administration is linked to multiple health benefits, with gut and immune health being the most well-researched.

3. Strain- and Dose-Dependence: While core mechanisms exist, the benefits of probiotics depend on the specific strain and dose.

4. Unique Athlete Microbiota: Athletes tend to have gut microbiota compositions that differ from sedentary individuals, primarily due to differences in exercise volume and protein consumption. However, it remains unclear whether these differences affect probiotic efficacy.

5. Enhanced Nutrient Absorption: In athletic populations, certain probiotic strains may boost the absorption of key nutrients like amino acids from protein.

6. Immune System Support: With about 70% of the immune system located in the gut, probiotics can promote a healthy immune response, reducing the frequency, severity, and duration of upper respiratory tract infections.

7. Gut Barrier Integrity: Intense exercise, especially in the heat, can increase gut permeability and the risk of systemic toxemia. Specific probiotic strains can improve the gut barrier function.

8. Recovery Enhancement: Selected anti-inflammatory probiotic strains have been linked to improved recovery from muscle-damaging exercise.

9. Optimised Dosing: The minimal effective dose and administration method of a probiotic strain depends on validation studies. Products should clearly list the genus, species, strain, and colony-forming units (CFU) at the end of their shelf life.

10. Potential Performance Benefits: Early research suggests potential benefits including improved body composition, lean mass, hormonal balance, reduced cortisol levels, lower exercise-induced lactate, and enhanced mood and cognition—but these benefits require further validation in athletic populations.

This statement from the ISSN underlines the importance of personalised probiotic supplementation and confirms that a tailored approach can help optimise your health, performance, and recovery (8).

InnerBuddies: Your Partner in Personalised Supplement Advice

At InnerBuddies, we’re committed to using scientific insights to help you reach your fitness goals. Our approach is built on:

• Personalised Assessments: We look at your unique gut microbiome and dietary habits.

• Science-Backed Recommendations: By reviewing studies on training adaptations, and probiotic benefits we tailor supplement advice that fits your needs not only for your fitness goals but also in other areas of your life. 

• Optimised Nutrient Support: We recommend a balanced, fiber-rich diet paired with fermented foods, and when needed, targeted probiotic supplementation to support gut health and enhance performance.

Our Top Tips for a Healthy Gut:

• Fiber is Key: Aim for a diet rich in fruits, vegetables, whole grains, legumes, nuts, and seeds. Gradually increase your fiber intake to around 30 grams per day.

• Enjoy Fermented Foods: Incorporate yoghurt, kefir, kombucha, and tempeh into your routine to boost your gut’s beneficial bacteria.

• Smart Supplementation: Use personalised probiotic supplements that consider the specific strains and dosages validated for athletic performance.

• Mindful Antibiotic Use: When antibiotics are necessary, take extra care to support your gut health through diet and supplementation.

Your gut is a powerhouse that can have a big impact on your training performance, recovery, and overall health. With an ever-growing body of research, it's clear that nurturing your gut microbiome is key to unlocking your full athletic potential.

At InnerBuddies, our mission is to provide you with personalised supplement advice that not only enhances your performance but also supports long-term health. Whether you're a competitive athlete or a recreational sports enthusiast, taking care of your gut could be the secret ingredient to your success.

Ready to boost your performance from the inside out? Let InnerBuddies guide you on your journey to a healthier, stronger you.

References: 

1. Varghese S, Rao S, Khattak A, Zamir F, Chaari A. Physical Exercise and the Gut Microbiome: A Bidirectional Relationship Influencing Health and Performance. Nutrients. 2024 Oct 28;16(21):3663.

2. Vechetti IJ, Valentino T, Mobley CB, McCarthy JJ. The role of extracellular vesicles in skeletal muscle and systematic adaptation to exercise. J Physiol. 2021 Feb;599(3):845–61.

3. Yuan X, Xu S, Huang H, Liang J, Wu Y, Li C, et al. Influence of excessive exercise on immunity, metabolism, and gut microbial diversity in an overtraining mice model. Scand J Med Sci Sports. 2018 May;28(5):1541–51.

4. Puccini V. Antibiotic Therapy and Athletes: Is the Mitochondrial Dysfunction the Real Achilles’ Heel? Sports Basel Switz. 2022 Aug 31;10(9):131.

5. Uchida M, Fujie S, Yano H, Iemitsu M. Aerobic exercise training-induced alteration of gut microbiota composition affects endurance capacity. J Physiol. 2023 Jun;601(12):2329–44.

6. Mancin L, Burke LM, Rollo I. Fibre: The Forgotten Carbohydrate in Sports Nutrition Recommendations. Sports Med Auckl NZ. 2025 Jan 8;

7. Gross K, Santiago M, Krieger JM, Hagele AM, Zielinska K, Scheiman J, et al. Impact of probiotic Veillonella atypica FB0054 supplementation on anaerobic capacity and lactate. iScience. 2024 Jan 19;27(1):108643.

8. Jäger R, Mohr AE, Carpenter KC, Kerksick CM, Purpura M, Moussa A, et al. International Society of Sports Nutrition Position Stand: Probiotics. J Int Soc Sports Nutr. 2019 Dec 21;16(1):62.