Your gut is home to bacteria, fungi, viruses and other microscopic organisms, most of which live in the large intestine. These microbes help break down food that your body can\u2019t digest on its own, allowing you to access more nutrients and vitamins.<\/p>\n
Some bacteria are considered beneficial because they\u2019re often found in people who are healthy, both physically and mentally. They produce compounds that appear to support wellbeing.<\/p>\n
The makeup of your gut microbiome isn\u2019t fixed. It changes based on factors such as what you eat, how old you are, how well you sleep \u2013 and, as this study shows, whether you exercise.<\/p>\n
Researchers at the University of T\u00fcbingen in Germany recruited 150 people who didn\u2019t normally exercise and asked them to do resistance training two to three times a week for eight weeks. Participants used either lighter weights with more repetitions (15 to 20) or heavier weights with fewer repetitions (eight to ten).<\/p>\n
Both approaches produced similar improvements in strength and body composition. The exercises included chest presses, abdominal work, leg curls, leg presses and back exercises \u2013 two sets of each.<\/p>\n
The researchers collected stool samples at the start of the programme, after four weeks and after eight weeks to track changes in participants\u2019 gut bacteria.<\/p>\n
Some people gained strength much faster than others. The researchers divided participants into \u201chigh responders\u201d \u2013 the top 20%, who increased their strength by more than 33% on average \u2013 and \u201clow responders\u201d \u2013 the bottom 20%, who gained less than 12.2%.<\/p>\n
The biggest factor determining whether someone was a high or low responder appeared to be their initial strength level.<\/p>\n
But the researchers also found something interesting: the people who gained the most strength showed subtle but significant changes in their gut bacteria that the others didn\u2019t.<\/p>\n
High responders showed increases in 16 types of bacteria and decreases in 11 others. Two bacteria in particular stood out: Faecalibacterium and Roseburia hominis.<\/p>\n
Both produce butyrate, a type of compound called a short-chain fatty acid. These compounds are created when gut bacteria break down fibre, and they serve multiple purposes: they provide energy for the body and help maintain a healthy gut lining, which prevents harmful bacteria from entering the bloodstream.<\/p>\n
Similar increases in these bacteria have been found in other studies<\/a> looking at exercise and the gut<\/a>. However, in this study, the researchers didn\u2019t find an actual increase in short-chain fatty acids in the stool samples \u2013 only more of the bacteria that produce them.<\/p>\n Not that simple<\/p>\n It\u2019s tempting to label certain bacteria as \u201cgood\u201d or \u201cbad\u201d, but it\u2019s not that simple. Throughout the study, some bacteria typically associated with good health decreased, while others previously linked to poor health increased.<\/p>\n This highlights an important point: everyone\u2019s microbiome is unique. The same bacteria might perform different roles in different people, depending on the individual and their overall health.<\/p>\n Everyone\u2019s gut microbiome is unique. We also can\u2019t say for certain whether the changes in gut bacteria caused the strength gains, or whether getting stronger caused the bacterial changes. Studies like this can show associations, but they can\u2019t prove cause and effect \u2013 the microbiome is influenced by too many factors to control them all.<\/p>\n Diet<\/a>, for instance, has a major effect on gut bacteria. Participants were told not to change their eating habits during the study, but it\u2019s extremely difficult to accurately track what people eat. <\/p>\n It\u2019s possible that some high responders changed their diet as they became more focused on fitness, and this could have contributed both to their bacterial changes and their strength gains.<\/p>\n What we can say with more confidence is that exercise appears to benefit overall physical<\/a> and mental<\/a> health and should be part of a healthy lifestyle regardless of what it does to your gut microbes.<\/p>\n This was a small study that still has to go through the peer-review process of being officially looke at by other scientists. But it has the potential to add to growing evidence that our lifestyle choices, including how much we move, can influence the microscopic world living inside us.<\/p>\n","protected":false},"excerpt":{"rendered":"Lifting weights just two or three times a week can significantly change the trillions of bacteria living in…\n","protected":false},"author":2,"featured_media":197400,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[46],"tags":[6647,102,56,54,55],"class_list":{"0":"post-197399","1":"post","2":"type-post","3":"status-publish","4":"format-standard","5":"has-post-thumbnail","7":"category-fitness","8":"tag-fitness","9":"tag-health","10":"tag-uk","11":"tag-united-kingdom","12":"tag-unitedkingdom"},"_links":{"self":[{"href":"https:\/\/www.newsbeep.com\/uk\/wp-json\/wp\/v2\/posts\/197399","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.newsbeep.com\/uk\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.newsbeep.com\/uk\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/uk\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/uk\/wp-json\/wp\/v2\/comments?post=197399"}],"version-history":[{"count":0,"href":"https:\/\/www.newsbeep.com\/uk\/wp-json\/wp\/v2\/posts\/197399\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/uk\/wp-json\/wp\/v2\/media\/197400"}],"wp:attachment":[{"href":"https:\/\/www.newsbeep.com\/uk\/wp-json\/wp\/v2\/media?parent=197399"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.newsbeep.com\/uk\/wp-json\/wp\/v2\/categories?post=197399"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.newsbeep.com\/uk\/wp-json\/wp\/v2\/tags?post=197399"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}![\"A](\"https:\/\/www.newsbeep.com\/uk\/wp-content\/uploads\/2025\/10\/file-20251007-56-22pppw.jpg\")
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\n Helena Nechaeva\/Shutterstock.com<\/a><\/p>\n