The type of training may affect the composition of the gut microbiome

Depending on the physical effort, strength or endurance, our intestines will be inhabited by slightly different, health-promoting bacteria, researchers point out. Understanding the mechanisms of response to training is a step towards personalized diet and training strategies based on the microbiome profile.

The gut microbiome plays a significant role in the body's physiological response to physical exertion, affecting, among other things, the level of inflammatory markers and the production of metabolites. Professional athletes tend to have a more diverse microbiome, which, as studies have shown, can translate into better performance. However, little is known about how specific forms of physical activity affect the composition of the microbiome.

In the latest study, scientists from the Małopolska Centre of Biotechnology of the Jagiellonian University and the Academy of Physical Education and Sport in Gdańsk looked at the differences in the gut microbiome of people who train professionally in strength, endurance and those who are only recreationally active.

The study participants took part in two exercise tests. One was the high-intensity anaerobic (strength) Wingate test, which is used to assess the body's anaerobic capacity and power potential. It involves pedaling maximally for 30 seconds on a special cycloergometer. The study used a modified version of this test, with participants performing two 30-second sprints with a 30-second rest in between, which provided a strong metabolic stimulus. The second exercise was the Bruce aerobic treadmill test, in which the load (speed and incline) is gradually increased.

The study results were published in Plos One https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0297858#sec016

"A deeper analysis showed that one third of the bacteria were unique to each of the studied groups. This may indicate subtle differences in the intestinal environment, potentially related to the dominant type of physical activity," the study's author, Dr. Kinga Humańska-Lisowska from the Jędrzej Śniadecki University of Physical Education and Sport in Gdańsk, told PAP.

Endurance athletes had higher levels of Blautia bacteria, which affect digestion, immunity, and body weight. They also had more fiber-degrading bacteria, which may support performance by extracting energy from their diet more efficiently.

It was also observed that people with the highest VO₂max parameter (determining the maximum amount of oxygen that the body can take in, transport and use) had more probiotic bacteria of the Bifidobacterium genus, such as B. longum and B. adolescentis, which may suggest their beneficial contribution to aerobic capacity.

In the group of strength athletes, after the Wingate strength test, the level of Alistipes communis bacteria increased significantly. They are believed to be involved in the regulation of inflammatory and metabolic processes, although their biological role remains unknown.

Both strength and endurance training participants showed a greater presence of bacteria species considered to be probiotics compared to recreational exercisers.

In the second study, published in Scientific Reports, the researchers integrated gut microbiome data with serum biomarkers to examine the body’s physiological response to different types of exercise. https://www.nature.com/articles/s41598-025-99485-9#Sec16

This was a continuation of the same study, supplemented with the analysis of selected markers of inflammation, oxidative stress and muscle regeneration.

Both endurance and strength training have been shown to induce characteristic biochemical changes in the body that are visible within 6–24 hours of exercise. What’s more, the microbiome can modulate these physiological responses.

The key differences were in the levels of two proteins - SPARC and adiponectin, whose changes correlated with, among others, the presence of Blautia massiliensis bacteria and the activity of molecular pathways related to, among others, nucleotide metabolism. These patterns differed between the groups of participants, suggesting that the gut microbiota may play a mediating role in the body's adaptive response to intense physical exercise.

Adiponectin is a protein hormone produced by adipose tissue. It regulates glucose and lipid metabolism, supports insulin sensitivity, and has anti-inflammatory effects. After the Bruce endurance test, its levels remained stable. However, after the Wingate test, they fell in all groups – probably in response to high metabolic stress.

"This result may reflect the body's acute response to maximum intensity physical exercise and a temporary limitation of the protective effect of adiponectin," said Dr. Humańska-Lisowska.

The researchers observed interesting results for the SPARC protein, a glycoprotein involved in tissue regeneration and immune processes. After the Wingate test, a significant increase in the SPARC protein level was observed only in the recreational group. In the athlete groups, the effect was much weaker. After the Bruce test, no significant changes were noted in any of the groups.

This suggests that SPARC may act as a potential marker of recovery and adaptation to exercise – and the weaker response in trained athletes may mean their body is better prepared for intense work.

"The maintenance of SPARC levels may indicate greater stability of the regenerative system in athletes – which may mean that their bodies are already better adapted to intense loads. In turn, the higher SPARC levels observed in the control group may reflect stronger regenerative stress or greater muscle damage caused by intense effort," commented the researcher.

Although, as Dr. Humańska-Lisowska emphasized, these findings require further research, they show that the gut microbiome may be an important element modulating physiological responses to training. In the future, a better understanding of these mechanisms may enable the creation of personalized diet and training strategies based on the microbiome profile and activity history of a given person.

Science in Poland, Ewelina Krajczyńska-Wujec

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