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A new study followed six college football players through an entire season and checked for evidence of those routine hits. They found it \u2013 just not where anyone expected.<\/p>\n
Hits that don\u2019t register<\/p>\n
The research was led by Dr. Kenneth Douglas Belanger, a biologist at Colgate University (Colgate<\/a>). <\/p>\n The team monitored six NCAA Division I players throughout one season to investigate how routine hits may affect the gut.<\/p>\n Their question hinged on what scientists call subconcussive hits \u2013 head impacts that fall below the threshold for a concussion diagnosis but still rattle the brain. <\/p>\n A football player can take 100 to 1,000 of these in a season.<\/p>\n Earlier work has linked them to short-term cognitive dips and later neurodegenerative risk, but no one had asked whether they touched the gut.<\/p>\n Looking for changes in the gut<\/p>\n The setup was meticulous. Helmet sensors logged every impact during practices and games, sorting them by force into five tiers. GPS units worn between the shoulder blades tracked physical exertion.<\/p>\n Players collected fecal samples \u2013 226 in total over the season. After each one, they answered a daily questionnaire covering sleep, stress, illness, caffeine, alcohol, NSAID use, and other variables that can touch the digestive tract.<\/p>\n Bacterial DNA from each sample was sequenced. Activity data was crunched. <\/p>\n Next, the researchers looked for patterns connecting how hard players were hit to changes in the gut microbiome<\/a>.<\/p>\n This includes trillions of microorganisms living in the intestines that regulate inflammation and talk to the nervous system.<\/p>\n A different bacterial mix appears<\/p>\n Hits had to clear a threshold to count for the short-term analysis \u2013 a session in the top 25 percent of impact load, followed by three quieter days. <\/p>\n Across 13 such windows, microbial composition stayed roughly stable for the first 24 hours. Then it moved. <\/p>\n Two to three days after a hard-hitting session, the bacterial mix in the gut looked measurably different from where it started.<\/p>\n That delay is the part worth pausing on. The hit happens on a Saturday. By Monday or Tuesday, with the player feeling fine and back at practice, something downstream has already changed.<\/p>\n Bacteria on the move<\/p>\n When the team drilled into which microbes were moving, a few names kept showing up. Coriobacteriales, Prevotellaceae, and Prevotella all dropped in abundance after impact-heavy days. Ruminococcus climbed.<\/p>\n These names have a track record. Prevotella declines have been tied to lower production of short-chain fatty acids, compounds that calm inflammation and help maintain the blood-brain barrier.<\/p>\n Ruminococcus, on the other hand, shows up at higher levels in people with inflammatory bowel disease \u2013 a different kind of company from the one a player wants to keep.<\/p>\n Across the season<\/p>\n The single-impact analysis was only half the picture. Researchers compared each player\u2019s early-season samples with their late-season ones. <\/p>\n Across the cohort, the microbiome at the end of the season looked significantly different from where it started.<\/p>\n Mixed-effects modeling \u2013 statistical machinery designed to separate one variable from a tangle of others \u2013 suggested the cumulative head impact load contributed to the season-long change.<\/p>\n That conclusion held even after accounting for changes in diet, exercise intensity, sleep, stress, NSAID use, energy drinks, and ten other factors. <\/p>\n Time itself, total physical strain, and pre-workout supplements also registered as influences.<\/p>\n Limitations of the study<\/p>\n Six players is a small group. There was no non-football control group, and the design cannot establish causation \u2013 only correlation. <\/p>\n All six participants were white males in their early 20s, which limits how broadly the findings apply.<\/p>\n What this study can do is open a door. A paper<\/a> on diagnosed concussions has already shown the gut reacts to brain trauma. This is the first work to extend that link down to the hits clinicians never see.<\/p>\n Until this study, \u201casymptomatic\u201d was the working assumption for the small hits. A player walks off, feels fine, plays again. <\/p>\n Now, there is biological evidence that something below the surface changes in the days that follow. Even when the player reports nothing.<\/p>\n That changes the picture in concrete ways. Trainers have reason to rethink recovery windows, and teams could eventually track cumulative biological changes across a season, not just the diagnosed injuries.<\/p>\n Complex organ systems communicate<\/p>\n Researchers also gain a new biological signal to chase \u2013 one a stool sample can capture without an MRI or a blood draw.<\/p>\n \u201cWe are only beginning to scratch the surface in our understanding of how these complex organs and organ systems communicate with and affect each other,\u201d said Dr. Belanger.<\/p>\n Larger groups \u2013 including women, who respond differently to brain injuries, according to a recent study<\/a> \u2013 will sharpen the picture. <\/p>\n The conversation about the long-term toll of contact sports just gained a biological variable nobody had measured.<\/p>\n The study is published in the journal PLOS One<\/a>.<\/p>\n \u2014\u2013<\/p>\n Like what you read? Subscribe to our newsletter<\/a> for engaging articles, exclusive content, and the latest updates.<\/p>\n Check us out on EarthSnap<\/a>, a free app brought to you by Eric Ralls<\/a> and Earth.com.<\/p>\n \u2014\u2013<\/p>\n","protected":false},"excerpt":{"rendered":"The routine hits that don\u2019t send football players to the sideline barely register in sports medicine. There are…\n","protected":false},"author":2,"featured_media":657986,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[563],"tags":[64,63,596,85],"class_list":["post-657985","post","type-post","status-publish","format-standard","has-post-thumbnail","category-football","tag-au","tag-australia","tag-football","tag-sports"],"_links":{"self":[{"href":"https:\/\/www.newsbeep.com\/au\/wp-json\/wp\/v2\/posts\/657985","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.newsbeep.com\/au\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.newsbeep.com\/au\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/au\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/au\/wp-json\/wp\/v2\/comments?post=657985"}],"version-history":[{"count":0,"href":"https:\/\/www.newsbeep.com\/au\/wp-json\/wp\/v2\/posts\/657985\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/au\/wp-json\/wp\/v2\/media\/657986"}],"wp:attachment":[{"href":"https:\/\/www.newsbeep.com\/au\/wp-json\/wp\/v2\/media?parent=657985"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.newsbeep.com\/au\/wp-json\/wp\/v2\/categories?post=657985"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.newsbeep.com\/au\/wp-json\/wp\/v2\/tags?post=657985"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}