Evidence that Exercise Increases
Good Gut Bacteria

& Tips for Staying Active in Winter Months

There is increasing evidence that regular exercise promotes the growth of beneficial bacteria in the colon. This is important because over 99.9% of the probiotic bacteria in the human gut microbiome reside in the colon’s anaerobic (non-oxygen) environment. This is where most of your all-important postbiotic metabolites are created when your probiotic bacteria ferment the fibers and polyphenols in your foods.

An increasing body of scientific evidence indicates that postbiotic metabolites function in multiple ways to promote and regulate your health. Conversely, poor diet and lifestyle factors encourage the growth of harmful bacteria in the microbiome, increasing the risk of heart attacks, strokes, diabetes, autoimmune diseases, and colon cancer.

Two new studies, one in mice and one in humans, report that exercise promotes the growth of beneficial bacteria in your colon and reduces the number of bad ones.

Exercise & Gut Bacteria in Mice

Researchers transplanted material from a group of exercising and sedentary mice into the colons of germ-free mice (mice with no bacteria in their gastrointestinal tract). The germ-free mice developed the same species of colon bacteria that they received from each donor group. Recipient mice that received fecal samples from the exercising mice developed much higher levels of beneficial bacteria that produce high levels of short-chain fatty acids, known to provide anti-inflammatory activity and help reduce cholesterol levels.ⁱ

The recipient mice were then given a chemical that causes inflammation, damages their colons, and causes colitis. Mice that received bacteria from the exercising mice had far less inflammation, far less damage to cells lining the colon, and exhibited much faster recovery times than those who had received bacteria from the sedentary mice.

Exercise & Gut Bacteria in Humans

Investigators monitored 18 lean and 14 obese female subjects in a supervised, endurance-based exercise program for 30 to 60 minutes, three days/week for six weeks. They were then instructed not to exercise for six weeks. After six weeks of exercise, the lean and obese subjects increased the number of beneficial colon bacteria that produce short-chain fatty acids known to suppress inflammation.

The lean subjects had the most significant increase in good bacteria after exercising, while the obese subjects had a more modest increase. Also, it was revealed that the exercise-induced changes in the microbiota were reversed once exercise training was discontinued.ⁱⁱ

These studies add to the body of scientific studies that indicate regular exercise is a vital lifestyle factor in maintaining a healthy microbiome.

Timely Tips for Staying Active in Winter Months:

• Join a Gym: Look for a local gym or fitness center that offers a variety of classes, from yoga to high-intensity workouts. Many gyms provide trial memberships, allowing you to explore options before committing.
• Utilize Technology: Use fitness apps or online workout videos. Many platforms offer free or low-cost classes that you can take from the comfort of your home.
• Create a Home Gym: Invest in essential equipment like resistance bands or dumbbells to facilitate workouts at home.
• Winter Sports: Engage in seasonal activities such as snowshoeing, cross-country skiing, or ice skating. These exercises are not only fun but also provide excellent cardiovascular workouts.
• Nature Walks: Take walks in parks or safe neighborhoods if weather permits. Walking outdoors can boost your mood and provide exposure to natural light.
• Walk Indoors: Use shopping malls or large indoor spaces as walking tracks. This is especially useful on particularly cold or snowy days.
• Community Centers: Check for classes at local community centers that offer various activities like aerobics, swimming, or team sports.
• Dress in Layers: When exercising outdoors, wear multiple layers to regulate your body temperature effectively. Start with moisture-wicking fabrics, add insulating layers, and finish with a windproof outer layer.
• Climb Stairs: Utilize stairs at home or work for quick bursts of exercise. Even short sessions can be beneficial.