Modern lifestyle factors such as irregular sleep, stress, and exercise patterns are increasingly recognized for their influence on the gut microbiome, according to a review published in Current Clinical Microbiology Reports. The review examines how behaviors like shift work, exposure to artificial light, and frequent travel can disrupt circadian rhythms and impact the composition of gut bacteria.
Researchers highlighted that the gut microbiota is not only affected by but also helps regulate circadian rhythms. Disruptions to these rhythms—caused by changes in light exposure or feeding times—can lead to altered microbial patterns. Animal studies have shown that mice lacking certain clock genes lose normal fluctuations in their gut bacteria. However, time-restricted feeding can restore some of this rhythmicity.
Sleep quality also plays a significant role in maintaining health through its effects on the microbiome. A large cohort study found that individuals with healthy sleep habits had a 17 percent lower risk of colorectal cancer compared to those with poor sleep patterns. Sleep deprivation was linked to impaired immune function and increased inflammation, as well as negative changes in the gut microbiota associated with cognitive and metabolic problems.
Exercise was found to promote beneficial changes in gut bacteria, particularly increasing genera like Akkermansia that are tied to reduced inflammation and better gut barrier function. In humans, structured endurance exercise improved metabolic markers and shifted the composition of the microbiome favorably. Furthermore, studies suggest that some people experience greater improvements in insulin sensitivity from exercise due to specific changes in their gut bacteria; these benefits could even be transferred between individuals via fecal transplantation in animal models.
Stress is another factor examined for its effect on the gut microbiome. The body's stress response involves complex interactions between the brain and peripheral organs through the hypothalamic–pituitary–adrenal (HPA) axis. Disruption of this system—through chronic stress or circadian misalignment—was shown in animal models to affect both gene expression related to circadian regulation and hormonal release patterns.
Despite growing evidence linking modern lifestyle factors with changes in microbial communities and disease risk, much of the mechanistic understanding comes from animal research rather than human trials. Most studies focus on bacterial populations within the gut; less is known about other microbes such as fungi or viruses or about non-intestinal sites like skin or oral cavities.
Additionally, large-scale human studies indicate that while lifestyle factors do shape microbiome variation, polypharmacy—the use of multiple medications—may have an even stronger effect.
The review concludes that further research into how diverse microbes interact with various aspects of modern living could inform new strategies for reducing disease risk associated with contemporary lifestyles.
