I second the section on air quality monitors. I only have a CO2 monitor, but find it really helpful for problems of the form “I feel vaguely KO. I wonder why that is… <consults CO2 monitor> Oh, I should’ve aired the room out hours ago.”.
Some additional notes on this topic: The monitor I have isn’t particularly good for this purpose. It was a test winner from Stiftung Warentest (the German customer review site), so maybe it’s particularly accurate, and I certainly paid as if it was. But it turns out you just don’t need a particularly accurate device for this purpose; it’s enough if the displayed values are sufficiently correlated with the actual ones. A cheaper device would have been just fine.
Furthermore, to maintain this (supposed) accuracy, the monitor has a truly ludicous design: Any time it’s disconnected and reconnected, like when it’s installed in a new room, it re-calibrates itself under the assumption that the room has just been aired out completely, and assumes that the current CO2 level is 400 ppm. Afterwards, it re-calibrates itself such that it assumes the lowest CO2 level in the last week was 400 pm. These two aspects make it utterly useless for measuring CO2 anywhere you can’t air out completely, like a cellar. (Though it’s fine in my room, which I air out regularly.)
In a second feature, the monitor has an optional CO2 alarm and begins beeping when the CO2 level reaches a set threshold like 1500-2000 ppm. Unfortunately, its CO2 measurements take a while, so when it beeps you either have to manually turn off the alarm each time (there’s no snooze button), or air out the room for 20+s before it stops.
In conclusion: monitors for CO2 or air quality yay, this device nay.
Watchband and ring fitness trackers will sometimes claim to report HRV, but they’re not very good. Measuring HRV requires very precise measurements, and the signal of the heartbeat gets fuzzier the further you are from the heart. When I look next I’ll be looking for something favored by HIIT nerdjocks, because HIIT also requires very sensitive measurements.
Health trackers vary a lot in quality, so it might be worthwhile to briefly check the Quantified Scientist Youtube channel (or even email him) for whether he has found any he could recommend for that purpose. I really like that channel for doing calibrated tracker measurements. Imagine a world where those kinds of product reviews were industry standard, instead of SEO content mills.
I second the section on air quality monitors. I only have a CO2 monitor, but find it really helpful for problems of the form “I feel vaguely KO. I wonder why that is… <consults CO2 monitor> Oh, I should’ve aired the room out hours ago.”.
Some additional notes on this topic: The monitor I have isn’t particularly good for this purpose. It was a test winner from Stiftung Warentest (the German customer review site), so maybe it’s particularly accurate, and I certainly paid as if it was. But it turns out you just don’t need a particularly accurate device for this purpose; it’s enough if the displayed values are sufficiently correlated with the actual ones. A cheaper device would have been just fine.
Furthermore, to maintain this (supposed) accuracy, the monitor has a truly ludicous design: Any time it’s disconnected and reconnected, like when it’s installed in a new room, it re-calibrates itself under the assumption that the room has just been aired out completely, and assumes that the current CO2 level is 400 ppm. Afterwards, it re-calibrates itself such that it assumes the lowest CO2 level in the last week was 400 pm. These two aspects make it utterly useless for measuring CO2 anywhere you can’t air out completely, like a cellar. (Though it’s fine in my room, which I air out regularly.)
In a second feature, the monitor has an optional CO2 alarm and begins beeping when the CO2 level reaches a set threshold like 1500-2000 ppm. Unfortunately, its CO2 measurements take a while, so when it beeps you either have to manually turn off the alarm each time (there’s no snooze button), or air out the room for 20+s before it stops.
In conclusion: monitors for CO2 or air quality yay, this device nay.
Health trackers vary a lot in quality, so it might be worthwhile to briefly check the Quantified Scientist Youtube channel (or even email him) for whether he has found any he could recommend for that purpose. I really like that channel for doing calibrated tracker measurements. Imagine a world where those kinds of product reviews were industry standard, instead of SEO content mills.