A compelling new study, led by researchers from the University of Illinois at Chicago, has identified a complex relationship between disturbed sleep patterns, elevated blood pressure, and disruptions to the gut microbiome. The robust animal study suggests these three factors influence each other in a bidirectional fashion, and the findings could point to novel new treatments mitigating the negative health effects of poor sleep.
While there currently is a large volume of ongoing research investigating the broad systemic influence of the gut microbiome on general health, the causal direction underpinning many of these relationships is still unclear. Hypertension, for example, has been associated with an imbalance in gut microbial populations. On the other hand, chronic sleep disruptions have also been linked with increased blood pressure and heightened risk of cardiovascular disease.
“We know that working at night can cause problems with your health, and the data suggest that staying awake all night can lead to high blood pressure, and, in some cases, eventually to heart disease, but it’s not clear what mechanisms underlie the development of these conditions,” explains Anne Fink, one of the authors on the new study.
This study, conducted in rodents, set out to examine the relationship between fragmented sleep, changes in the gut microbiome, and blood pressure. For 28 days the animals were subjected to constant sleep disruptions, while changes to blood pressure and gut microbial populations were intermittently measured.
"When rats had an abnormal sleep schedule, an increase in blood pressure developed – the blood pressure remained elevated even when they could return to normal sleep," explains Katherine Maki, another author on the new research. "This suggests that dysfunctional sleep impairs the body for a sustained period."
This apparently causal relationship between disrupted sleep and increased blood pressure was not a surprise as it has been observed in humans experiencing sleep deprivation. However, what was unexpected was the delayed effect of sleep disruption on the gut microbiome.
Whereas blood pressure increases were detected relatively soon after the animals’ slumber was disrupted, it took a week of consistent sleep interruptions before imbalances were seen in the gut microbiome. Increases in bacteria associated with inflammatory processes were ultimately detected, and these changes did not immediately return to normal when the animals were allowed to recommence sleeping naturally.
“When the sleep disruption stopped, everything did not come back to normal immediately,” adds Maki. “This research shows a very complex system with the presence of multiple pathological factors.”
The researchers do conclude these interactions between sleep disruption, gut microbiome changes, and blood pressure, are not unidirectional. Although microbiome dysbiosis followed sleep disruptions and blood pressure increases, the researchers suggest gut bacteria interventions, such as targeted probiotics, could hypothetically mitigate the hypertension caused by poor sleep.
“Although it appears that SF [sleep fragmentation] acts initially on blood pressure without gut microbial mediation, the gut microbiome is clearly impacted by extended SF,” the researchers write in the study’s conclusion. “Thus, understanding the microbiota may be particularly important for identifying interventions targeting the gut microbiota that reduce cardiovascular morbidity in patients with sleep disorders. Augmenting the gut microbiota to increase or decrease levels of metabolites linked with reduced or elevated blood pressure levels, respectively, may prevent SF-induced blood pressure elevations when SF is unavoidable.”
The ultimate outcome of the research will be to find interventions that can minimize the negative health impacts of disrupted sleep, particularly in those whose work or home life result in disordered sleep schedules. The next steps for the researchers will be to validate the findings in human subjects, and begin homing in on particular gut bacteria metabolites and how they are influenced by sleep disruptions.
The new research was published in the journal Physiological Genomics.