If you’ve been tossing and turning at night, blaming your pillow or your overactive mind, scientists say you might be looking in the wrong place. The real answer could be hiding in your gut.
A new study published in General Psychiatry has revealed a surprising connection between the bacteria in our digestive system and our ability to sleep soundly.
It suggests that the state of your microbiome might be just as important as your bedtime routine when it comes to fighting insomnia.
The Research Behind the Discovery
Shangyun Shi, from Nanjing Medical University in China, led the research that dug deep into this gut-sleep connection.
Using data from over 386,000 people with insomnia and comparing it to microbiome studies involving more than 26,000 participants, the team looked at 71 common groups of gut bacteria.
They found that certain bacteria could slightly increase or decrease the risk of insomnia — and the relationship works both ways.
Poor sleep appears to change the balance of bacteria in the gut, while the gut’s bacterial makeup can also influence how well you sleep.
Which Bacteria Matter Most
The analysis revealed 14 types of bacteria linked to a higher risk of insomnia and 8 types linked to a lower risk.
But insomnia itself was also found to dramatically shift gut composition — reducing some bacteria by as much as 79% and boosting others more than four-fold.
One standout group was odoribacter. Higher levels of this bacteria are generally linked with a healthier gut and less inflammation.
Lower levels, on the other hand, have been seen in people with inflammatory bowel disease, obesity, and type 2 diabetes.
Why This Matters for Future Treatments
Shi believes these findings strengthen the evidence for a complex two-way relationship between gut health and sleep quality.
If that’s true, future insomnia treatments might involve adjusting gut bacteria levels — perhaps through probiotics, prebiotics, or even faecal microbiota transplants.
However, there are still gaps to fill. The study only looked at participants of European descent, and lifestyle factors like diet weren’t included — both of which are known to affect gut bacteria.
How Common Is Insomnia?
The NHS estimates that about a third of Britons struggle with insomnia, and US figures are very similar.
That means millions of people could potentially benefit from gut-focused therapies in the future.
What Happens When We Go Without Sleep for Days
Staying awake for too long isn’t just unpleasant — it can be dangerous.
Within 24 hours, hormone changes can raise blood pressure.
By the second day, your body struggles to process glucose, leading to intense carb cravings, a drop in body temperature, and a weakened immune system.
While no human has been proven to die directly from insomnia, a University of Chicago study in the 1980s found that rats died after 32 days without sleep.
Theories suggest they developed hypothermia, suffered immune collapse, or became fatally stressed.
Famous Cases of Extreme Sleep Deprivation
One of the most infamous cases is Michael Corke, a music teacher from Illinois who reportedly went six months without sleep due to a rare disease called fatal familial insomnia.
He died at 42, though it’s unclear if lack of sleep was the sole cause.
The record for the longest time awake belongs to Randy Gardner, a 17-year-old student from San Diego in 1964.
He stayed awake for 11 days and 25 minutes during a school project — and by the end, he was experiencing memory loss, slurred speech, and hallucinations.
