Blog Post 5 – 10/6/24

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This week, we will continue our discussion about the microbiome by exploring how different lifestyle factors influence the diversity and health of gut bacteria and therefore your overall health. We’ve all experienced that awful brain fogged feeling after a bad night of sleep. But, studies have actually shown that chronic reduced sleep quantity and quality may alter the composition of the gut microbiome– something that an afternoon nap may not fix. In fact this relationship is bidirectional as studies have also found that the microbiome composition may also influence sleep patterns. For example, higher levels of Faecalibacterium have been linked with longer sleep duration, while higher levels of Bacteroides have been associated with increased difficulty of falling asleep. 

Overall, there is evidence that increased total sleep time is positively associated with total microbiome diversity. Disrupted sleep from conditions such as sleep apnea or insomnia has also been shown to alter the gut microbiome composition, decreasing the numbers of beneficial bacteria and increasing the harmful bacteria. More specifically, phyla richness of Bacteroidetes and Firmicutes has been associated with higher quality sleep. This strong association between sleep patterns and gut microbiome composition was also supported by studies that found a positive correlation between gut microbiome diversity and interleukin-6, a cytokine known for its effects on sleep. Ultimately, reducing hours of uninterrupted sleep harms the body’s natural circadian rhythm, which harms communication along the gut-brain axis, promoting an unhealthy gut microbiome. 

However, sleep isn’t the only lifestyle factor shown to have intense effects on the gut microbiome! Regular physical exercise is another key player in promoting a healthy, diverse gut microbiome.  According to one systematic review of evidence around this topic, women who perform at least 3 hours of exercise per week have increased A. muciniphila, a beneficial bacteria associated with lower BMI and increased metabolic health. Multiple studies have also associated higher cardiorespiratory fitness levels with a higher ratio of Firmicutes to Bacteroidetes. Increased levels of aerobic exercise and consequent maximal oxygen uptake (VO2max) has been shown to increase microbial diversity overall as well as the numbers of butyrate-producing species. Since butyrate feeds cells of the intestinal lining, this promotes a healthy gut barrier and prevents “leaky gut.”

Although there has been less research on the effects of strength training on the gut microbiome, this is also understood to have positive effects. According to another systematic review, no studies have found strength training to alter the composition or diversity of the gut microbiome, as was found with aerobic exercise.  However, resistance training has been shown to reduce gut inflammation through multiple other mechanisms. One key biomarker of poor gut barrier function is zonulin, a protein that regulates the permeability of the intestine lining. Studies have reported significantly lower levels of zonulin amongst individuals who engage regularly in resistance training. Mucin biosynthesis has also been associated with resistance training. This is also important to preventing gut inflammation as mucin protects epithelial cells from stress-induced damage. By preventing leaky gut syndrome, resistance training consequently protects the gut microbiome. 

With such profound effects on the microbiome, it is important to maintain quality sleep hygiene and regular physical exercise to promote a healthy and diverse gut microbiome. As we’ve discussed in previous posts, a healthy gut microbiome works wonders beyond improved GI functioning. In fact, the microbiome has extreme effects on the nervous system, endocrine system, metabolic system, and immune system pathways, as noted in this article posted by Stanford Lifestyle Medicine. The microbiome both regulates and produces neurotransmitters and hormones that are critical in mood regulation and overall mental-wellbeing. Improved sleep and exercise also promotes immune function and decreased inflammation by improving the diversity of the microbiome. 

As we’ve suggested, improved quality sleep hygiene and regular physical exercise are an important treatment for gut dysbiosis. Many metabolic diseases such as obesity and diabetes have been associated with such gut microbiome dysbiosis through a variety of mechanisms in ample scientific studies. The gut microbiota is crucial in maintaining systemic homeostasis and overall wellbeing through the metabolism of nutrients as well as the maintenance of the immune system. Therefore, we should do our best to protect it with adequate levels of aerobic and strength exercise as well as improving our sleep habits. So, hopefully next time you will reconsider that afternoon coffee and decide to take your dog on a walk instead!