Fixing my sleep, Part 3: The overnight sleep study

I have slept with 25 different electrodes and sensors attached to my body. I have slept while being videotaped by a stranger. I have slept with multiple sensors inside my nose.

An overnight sleep study, also called polysomnography , from the Latin many-sleep-record, does just what its name implies: it records a bunch of sleep stuff:

  • Brain waves
  • Pulse
  • Blood oxygen
  • Muscle activity in legs, chest, abdomen, and jaw
  • Air flow through the nose and mouth
  • Heart rhythm
  • Snoring or other sounds
  • And a whole lot more — in fact, enough data to diagnose 84 different sleep disorders, according to the sleep clinic.

The overnight sleep study took place at my local MedSleep clinic. As instructed, I got there at 9:00 pm exactly.

Mysteriously, one other patient was already there, although MedSleep’s (slightly bossy) instructions had been very clear: “Doors do not open before 9:00 pm!” Had they perhaps crawled in through a window, in an act of insomniac desperation?

Amanda the sleep technologist greeted me at the front desk with a smile, then showed me to my boudoir.

“Bedroom# 2” was a windowless space that’s used for appointments during the day — in fact, it might have been the very room in which I teleconferenced with Carey Marie during a previous visit (see Fixing my sleep, Part 2: First visit to the sleep clinic).

The room had a Murphy bed, and looked like a basic motel room. On TripAdvisor, it would definitely be in the Budget category, and might lose points due to its cold laminate floor and lack of TV, minibar, and room service. (What? No chocolates on my pillow?) However, it was spotlessly clean, and the bed and pillows were comfortable.

There was also a freshly renovated bathroom with lots of fluffy towels and a large shower. Patients are welcome to shower in the morning before heading to work.


After I filled out a questionnaire on how much stress, exercise and caffeine I’d experienced that day (not much), Amanda asked when my usual bedtime was.

“Now!” I responded. She said she’d do me first, because the mysterious other patient (who I never actually saw) had a much later bedtime.

Sensors galore

So, I put on my nightgown and Amanda began attaching a tangle of coloured cables to various portions of my anatomy. Starting from the top and working down:

  • Several sensors on my scalp and forehead to detect brainwaves and stage of sleep
  • 2 airflow sensors in my nose, one for nasal airflow, and one held in the nose but sticking out over the mouth to measure oral airflow
  • Sensors on my chin and jaw for detecting REM sleep (apparently your jaw relaxes when REM sleep starts)
  • A small microphone on my voicebox for detecting snoring
  • Electrodes on my chest for capturing heart rhythms
  • A belt around my chest, and another around my stomach to measure the muscle movements associated with breathing
  • A sensor for pulse and oxygen on a finger
  • One electrode on each leg, on the tibialis anterior muscle on the front of the lower leg  (Amanda the sleep tech turned out to be a biochemistry student). This was to check for restless legs syndrome (RLS) and periodic limb movements. The latter happens while you’re asleep; RLS occurs while you’re awake, preventing you from sleeping.
  • Plus a few I’ve probably forgotten!

All the sensor-attaching took about an hour. Apparently it usually takes 45 minutes, but I asked a lot of questions.


All wired up and rocking my LL Bean flannel tent. The red dots on my forehead are markers for electrode placement.

Amanda turned my light out at 10:30 using a switch outside the room. It reminded me of boarding school, where the matrons controlled our dorm lights from a single master switch.

There was neither a light switch inside the room nor a bedside light, and I wasn’t allowed to keep my cellphone on the night table (my watch was OK, though). I got the sense MedSleep really wanted me to sleep. No reading! No surfing!

Would I be trapped all night in my dark, windowless little room, tethered by the sensors? No, if trips to the bathroom were needed, I could call out to Amanda and she’d come and unhook me. The room featured a wall microphone for this purpose, plus an infrared camera so she could watch and record my sleeping positions and activity.

I did end up calling Amanda several times during the night, once for more blankets, and three times for bathroom trips. It was simple for her to unplug me, because all the sensors connected into one master plug near the head of the bed.

I got the sense Amanda had been told “If the patient wakes during the night, don’t engage them in conversation.” She wasn’t at all chatty after lights-out — one-word answers only — whereas she’d been quite conversational while we were getting set up. It felt a bit strange, but I appreciated MedSleep’s commitment to ensuring I slept — they seemed to have thought of all the details.

A restless night

As for the sleep itself, as is often the case, I was “tired but wired” — exhausted, but not at all sleepy or drowsy. Helpfully, my body decided to put on a display of both my restless legs and my benign heart palpitations. This melange of disturbances combined with my already-frazzled state meant I wasn’t able to fall asleep until about 2:30 AM.

Amanda was patient with all my awakenings and goings-to-the-bathroom. She came into my room about 10 times (no exaggeration) to reattach sensors that had become unstuck with all my fidgeting and restless-legging — she was great.

It actually surprised me that I could sleep at all, with all the sensors. I tried to sleep on my back as much as I could, in case I was stopping breathing because of sleep apnea. I wanted to give them the best opportunity to catch me doing this (sleep apnea is typically worse when you sleep on your back). I also know I was in REM sleep for at least some of the time, because there were vivid, vivid dreams.

Amanda woke me at 6:00 and I was up and on my way, wondering how I was going to make it through the work day on less than 4 hours’ sleep. And more than that, wondering how I’d be able to wait the 3 weeks to get the results of the study! As I drove home from the clinic, I was hoping so, so much that they’d find something — anything — that was fixable.

Pro tips for your overnight sleep study:

  • Don’t study for your sleep study! Your sleep is what it is. If you have something going on — sleep apnea, or whatever — they’ll detect it, regardless of whether you think you slept well or poorly.
  • If you like a glass of water in the middle of the night, bring bottled water. There are many electronic things on the bedside table, and no bedside light. I brought a little bottle of Perrier.
  • You won’t have time for a bedtime wind-down routine, and you won’t be able to read in bed (boo!)
  • Wear slippers. It’s a hard, cold, medical-office floor, and you have to sit there for a long time in your jammies getting all the sensors attached.
  • Bring a snack for the morning; there’s no breakfast or coffee offered. I brought more bottled water and some nuts.
  • You may not see any other patients — I didn’t. Alas for my dreams of a cozy pre-sleep-study pajama party in the waiting room, swapping insomnia war stories.
  • You’re not allowed to take any sleep supplements or sleep medications after midnight, because the clinic is concerned about your driving safety in the morning. Strangely, they’re not concerned about your driving safety when operating on 4 hours’ sleep due to *not* taking your usual middle-of-the-night sleep supplements.

Stay tuned for Part 4, coming soon, in which I get the results of the overnight sleep study.


This is post #3 in my series on sleep:


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