I've noticed I sleep better when I sleep separately from my wife. I'm the more violent sleeper, so it's not movement related, so I'm wondering if it's air quality related.
If possible, keeping a bedroom window a bit open makes a noticable difference. Avoid closing bedroom door too.
Similarly, if you work from home, make sure to create a draft once in a while.
We got an Aranet4 CO2/humidity/temperature sensor mostly out of curiosity two months ago. Outdoors it's ~430 ppm CO2. 500-1000 ppm indoors is considered okay (according to the defaults), 1000-1400 ppm high, and >1400 ppm bad.
It's amazing how you don't notice how it slowly creeps up to 900-1000 and beyond. Without the device I would notice, except that I'd slowly get tired. I'd probably also drink more coffee. The device helps you see what's going on and how bad it is. Creating a big draft for 5 minutes clears everything out.
Also, you can definitely see from the historical data when one goes to bed in a ~12 m2 bedroom and then an hour or so later the second person goes to bed. Same if one gets up before the other. Definitely good evidence that keeping a window open is a good thing (if you got clean air outside)
It has made me notice "stuffy" air more keenly and helps me avoid it. If I'm stuck in a physical meeting room at work I take lots of walks and breaks. etc.
I haven't tried the CO2 sensor in the bedroom. We like to sleep with fans on and the bedroom door open, which I suspect helps somewhat (depending on how drafty one's house is overall) although is obviously not as effective as having a window open.
It's currently really cold where I live, and I am trying to limit outside air coming in as much as possible. This then leads to the air having uncomfortably high levels of CO2, as confirmed using an air quality sensor.
Good insulation only works with good ventilation anyways, the goal of insulation isn't to make an house completely airtight
Look into these things: https://en.wikipedia.org/wiki/Heat_recovery_ventilation
The average person exhales about 1kg of CO2 per day. That's 542L per day. Let's say you produce 20% of your daily CO2 output during the night, since your metabolism is lower when you're asleep. That would be 108L per person per night, or 216L for two people.
The average American bedroom is around 120-130sqft, or 11-12 square meters. Assuming a height of 8 feet, the total volume of your bedroom is around 25-30KL. Pumping 216L of CO2 into a sealed room of that size will result in a CO2 concentration between 720 and 864ppm. That's not high enough to cause immediate medical problems, but it might have more subtle effects, especially if your bedroom is small or if your metabolism is higher.
720 and 864ppm is probably the lower limit for a completely empty room.
CO2 measurement gadgets are useful for measuring how stagnant your air is, but the above parcel of questions is a great predictor: if your answers are No for all questions, then you’re probably spiking CO2/humidity uncomfortably high at night.
Changing any of those answers from “No” to “Yes”, in any way that increases the amount of indoor air exhausted outdoors from your bedroom, and/or outdoor air drawn into your bedroom, may help a lot.
Measuring relative CO2 levels using daily graphs from a gadget is an excellent indicator of whether any change had an effect.