What is it like to spend a night in a sleep lab? How easy is it to sleep hooked up to numerous cables? And is there a link between the microbiome and sleep?
What happens during a sleep study?
Sleep is an essential part of our daily routine and health. Lack of sleep can be detrimental to our well-being.
Insomnia is a sleep condition that affects around one-third of the population of the United States, with 10–15 % of people experiencing “severe and chronic insomnia.”
The National Sleep Foundation describe insomnia as a condition in which a person experiences unsatisfactory sleep despite having the opportunity to sleep. In practical terms, this means trouble falling or staying asleep.
My mother has been living with insomnia for many years. Sleep is a regular topic in our conversations.
In my role as Research Editor at Medical News Today, I come across research studies into sleep regularly.
But, despite our insights into why sleep is important, what causes insomnia is not entirely clear.
A few months ago, my mom took part in a study looking into a link between the microbiome and sleep. I was very keen to speak to both her and the researcher leading the study afterward.
So, here is what happened when Mama Martin spent a night in a sleep lab.
I arrive at the Advanced Sleep Research Institute in Berlin, Germany, at 8.00 p.m. A medical student is on duty. There are two people here today that she is looking after. She will stay awake all night to monitor our progress.
The medical student takes me to a room with a single, hospital-style bed. There is also a TV. When you lie in the bed, you can see the camera that will record your sleep.
Next, she attaches the electrodes.
She puts two on my legs and several on my upper body, which are linked to the ECG. She then places more electrodes on my upper arms, hands, and a lot on my head.
The student also attaches a mask to screen for sleep apnea to my face. It’s hard, and the indents will remain visible on my face for a while after I take it off in the morning.
Finally, she attaches an oxygen monitor to my finger. It has only taken about 5 minutes to get me prepped, but I find it hard to imagine that I will ever go to sleep like this.
As soon as my preparation is complete, I lie down.
A few minutes later, the medical student’s voice comes on over the speaker. She asks if I can hear her. Then she asks me to do a vision test — look left, look right, open eyes, close eyes.
Next, we do a breathing test. I breathe in, breathe out, through my nose, through my mouth, hold my breath. This way, she can check that all the monitors are working correctly.
If I need to go to the bathroom, I need to call her so that she can detach me from cables. I don’t drink much in the evening so that I won’t need to use the bathroom in the night.
The lights go off at 10.00 p.m.
Once I fall asleep, the clock starts ticking down the 8 hours allotted sleep time.
The cables are not very comfortable, and I notice them every time I wake up. But, contrary to my expectations, I still manage to sleep fairly comfortably.
I have had trouble with my sleep since 2007. At the time, I had a lot of stress at work, including some incidences of bullying. Then I lost my husband in 2010.
My insomnia has been the same since the start. Most nights, I listen to audiobooks when I wake up and can’t go back to sleep.
I listen to stories that I already know, so they are not too exciting and pick soothing stories.
During my night at the sleep center, I slept relatively well, but I thought I had slept really badly.
I was awake at around 4.00 a.m. I wasn’t allowed to listen to my audiobook that night, so I used a relaxation breathing technique. I thought I was awake for a long time then.
When I find out the results, I am surprised. I was, in fact, not awake for long at all. And there were some unexpected revelations in the data.
I didn’t know that I sleep on my front. I also apparently sleep a lot on my right side, although I know that I mostly fall asleep on my left side. I never knew that I move so much when I’m sleeping.
At the end of my 8 hours of sleep, the medical student wakes me up. Then comes the rather lengthy job of washing the sticky residue left over from the electrodes out of my hair. I was told before my visit to bring shampoo, but I wasn’t prepared for quite how long this would take.
After my night at the sleep center, I send off my sample for the microbiome analysis.
The results show a possible imbalance in the composition of my gut microbiome. Specifically, they indicate that I have a higher risk of leaky gut syndrome and histamine intolerance.
How that links to my sleep is not clear at the moment.
After speaking to my mom, I also caught up with Katharina Lederer, who is a medical practitioner in Berlin. This study is part of her medical Ph.D. thesis.
Firstly, I asked Lederer if she had spent a night in a sleep lab herself.
“Yes, I have, and my experience was surprisingly [good]. Most patients ask how they are supposed to sleep with cables on their heads, legs, chest, and sensors on their fingers. But most people, as I did, fall asleep quite quickly.”
Lederer also explained that “most people are surprised how long they actually sleep.”
“Our perception of how long we sleep can be hours off our actual sleep time. Especially, people with insomnia feel that they sleep [for a much shorter time] than they mostly do due to the frequent sleep interruptions,” she told me.
Is there a link between the gut microbiome and sleep? Lederer thinks so.
“In my daily practice in the sleep laboratory, I encountered many patients who don’t just have trouble sleeping but also problems with their bowels, including pain, diarrhea, or constipation,” she explained.
“Both conditions have some common risk factors, such as high stress levels, insufficient movement during the day, and also nutrition.”
Lederer explained that research links our brains and our bowels via the gut-brain axis.
So, what is happening in this sleep study?
“The first step was to find out if people with insomnia suffer from more gastrointestinal problems than their healthy counterparts. This seems to be the case, but the numbers of the study are still too small to give a statistical significance,” Lederer said.
“In a second step, we are examining the microbiota of a group of patients with insomnia and comparing them to a healthy control group. Unfortunately, this is still in process.”
But could changing a person’s microbiome improve their sleep, or would changing their sleep affect their microbiome?
“There are a few studies already showing that sleep restriction can have an effect on the microbiota,” Lederer explained. “I suspect that there is also an influence the other way around, of the microbiota on our sleep, but this has only been shown in limited studies with mice yet.”
My final question to Lederer was whether taking part in a sleep study changes people’s attitude toward their insomnia.
“I hope so,” was her reply. “You can’t fix any sleep problem in a day. Most patients suffer from sleep disorders for many, many years before they come to the sleep center.”
“The brain is so used, almost conditioned, to wake up in the middle of the night or to connect the bed with negative emotions that it takes a while until sleep disorders are treated,” she continued.
This was certainly the case for my mom. She has, in the past, used an activity tracker to monitor her sleep but was not sure how much she could trust the results.
“Taking part in a sleep study has clarified for me that I actually sleep much more than I thought,” she told me.
My mom and Lederer also discussed recommendations for sleep at the initial consultation.
These include no reading or using a phone in bed, not exercising vigorously too close to bedtime, not eating or drinking caffeinated drinks for several hours before going to bed, not watching anything too exciting on TV, and getting up 8 hours after falling asleep.
Since her night at the sleep center, mom’s sleep hasn’t changed.
But she feels more confident in the amount of sleep her activity tracker shows her.
“I feel better about my sleep after seeing the results of my night at the sleep center. I am also mindful of the good sleep hygiene tips that I learned.”