I hope Garmin sees your passion project and greenlights it for inclusion. You have the right approach to ensuring folks are at their optimal health to grow intellectually as a person.

> Often, it would also contradict how I was internally feeling. I’d wake up feeling rested, see my stats are low, and play a game of chess out of algorithmic rebellion, only to feel my mind up against a barrier and handedly lose.

It would be better to only look at the stats after playing if you want to verify it, this could easily be a self-fulfilling prophecy.

The biggest thing for me is I don't understand how people can sleep with these watches on, it's so uncomfortable to me personally which is why the different ring technologies appeal to me more. I just wish either Garmin made one or that there was one I didn't have to buy a subscription to use.

I really wish Garmin had an official API that can be used by their users instead of the reverse-engineered solutions (although they're very good), but they're at the mercy of Garmin.

Lot of hate on Garmin sleep tracking in this thread, but I love it.

Maybe it is not super accurate, but it was eye-opening for me to see how the score changes for the worse even with a little bit of alcohol. I am way more careful with when and how much I drink since I've started wearing a Fenix 6 few years back

I didn't believe the stress numbers on my Garmin watch were very meaningful until I started taking Nebivolol (an atypical beta blocker) because there were so many gaps (even when I was sitting) that I didn't feel I could eyeball them or trust averages over time.

Taking that drug, however, it sees far fewer gaps and I show up in the blue "rest" zone most of the time.

I've been watching my heart rate a lot in the last month part because of health concerns and part because of a new stance I am practicing that has a physical component (e.g. adjusted gaits that are energy efficient) and a mental component, being an oceanic reservoir of calm with close mind-body-environment coupling 95% of the time but disconnecting that connection under peak stress -- like I am standing between two people who are screaming at each other and holding a barrier at my chest that I don't let my breathing cross and glance at my watch and my HR is 52 and it is not just the nebivolol talking because when I lose my shit it would be more like 70.

People taught me conventional Pranayama (diaphragmatic breathing) as a kid and it never helped me in "lose my shit" situations involving unstable environments and moral injury, with the intense practice I was doing recently it was clear to me that I was never going to do it better and I started researching emergency techniques for managing sympathetic overload and that one worked for me and now I feel like one of the people in [1] particularly when I show people my HRV web app [2] and demonstrate that I can turn my Mayer oscillation off

[1] https://en.wikipedia.org/wiki/Scanners_Live_in_Vain in the sense of ironclad autonomic control but with full sensory perception

[2] ... soon to be on Github

Absolutely love this kind of project, combining different data sources to predict/model how you're doing. I also use chess as a proxy for my brain is working!

I've tracked sleep using a number of devices and algorithms and I haven't found a single one that regularly aligns with what and how I feel.

I know it's tracking real data, but the conclusions feel completely made up.

What are other people's experience -- especially from those who are more bullish about sleep tracking?

> exercise-induced fatigue impairs complex cognitive tasks

Apparently your study is strictly about cardio.

Heavier compound lifts can surely knock me out for 30 minutes to 2 hours. I don't know how in the heck people train in the mornings. But a lot of this is because they are complex cognitive tasks.

Since this talks about sleep quality I want to add something that was almost unknown to me for over 30 years. Smartwatches AFAIK don't have CO2 sensors. It seems to me though, that that would be extremely useful for sleep quality tracking. I have just a couple of years ago found out that CO2 levels are having the highest impact on my sleep quality besides temperature. I can highly recommend getting a CO2 sensor to get a good feeling for that effect. Also understand how much air is available in your room and how much CO2 your body produces per hour. I totally underestimated this until I was able to measure it. In a small sleeping room with closed doors the amount of CO2 will reach unhealthy levels at the end of the night.

In Soviet Russia, intelligence tracks your smartwatch.

Isn't it a well-known fact that Garmin has terrible sleep tracking? The wearables can't handle deep sleep at all; even Muse with EEG can't reliably predict it, so I wouldn't be drawing conclusions here.

A small curiosity: I recently learned that sleep trackers in commercial wearables are terrible for people with sleep disorders like apneas, UARS, etc. It makes sense, as this isn't a typical dataset, but it's worth knowing.

https://www.youtube.com/watch?v=6FAz7QGmlBM

A petty correction to this excellent post: you say "Even a single serving of alcohol disproportionately impares REM sleep", but your source says "Reductions in REM sleep were observed starting at approximately 2 standard drinks".

Has anyone looked into creatine? I've seen more mentions of creatine supplementation for cognition performance.

see https://fitnessvolt.com/rhonda-patrick-and-darren-candow-cre... and https://www.foundmyfitness.com/topics/creatine

Not much research in this area and I don't see anyway that a smartwatch can/could track this.

I work in neurotech/sleeptech and though I commend @dmvaldman on the project, it falls for some of the common flaws of current sleep medicine/research and some strange decisions in the program itself.

Measuring sleep by time is an antiquated idea, and the industry is just barely starting to move away from this metric. You wouldn't measure your diet based on how much time you spend chewing.

Decreased slow-wave activity, the hallmark of deep sleep, can increase time spent in deep sleep as your brain tries to compensate for the lack. This only works to a certain point, and with significant decrease, such as after drinking alcohol, your brain is unable to make up for the deficit and is actually unable to stay in deep sleep. The deep sleep length doesn't map directly to function.

Chess is an interesting metric because there is an opponent being played against, so what does that really say about the players mental clarity? There are too many factors.

I wonder if sleep regularity (consistent wake in particular) was a metric which was fed into the algorithm, and if it did not correlate?

Though many people say "garmin (smartwatch X) isn't good at tracking" that misses the point that tracking time isn't a valuable metric, and why so many people say "my sleep score doesn't match what my watch tells me".

Beyond just tracking, we have the ability to directly enhance the Neural Function of Sleep, and this is what we're working on at https://affectablesleep.com

However breaking people away from the "sleep time metric" is a challenging one.

I hear that the performance on Dual n-back is exceptionally sensitive to sleep quality. You might feel totally fine but notice that your cognition has actually tanked in measurable ways.

I love this, the interday variability in my intelligence is extremely annoying.

Which techniques did you try, and which worked for you?

I use an Android app called "Sleep", it just works by accelerometer with your phone on the corner of your bed. I've found it's not really good with its automatic rating and suggestions, but the activity graph has an extremely reliable wave pattern on the mornings I am well rested. Like an hour and a half of no movement at all, then an hour of restlessness, which repeats through the night. Usually the hour of restlessness even has the same pattern each time it happens. But any other pattern and I generally feel tired the whole morning.

Originally I got this app for its alarm, it tries to go off in the half hour before the alarm time when you're already partially awake. The sleep tracking was just a bonus.

I find Garmin's sleep tracking "accurate" in that it typically matches how I feel the next day, but that also makes it not terribly useful because I don't really need a gadget to tell me when I feel tired. Mostly I wear the watch to sleep out of inertia and in case I need a flashlight in the middle of the night.

But there have been three aspects of sleep tracking that have been mildly useful:

1. A few times my heart rate variability went haywire and the sleep scores didn't match how I felt, and it turned out I was sick and had not yet noticed any symptoms. Since then it has been mildly useful to have a heads up when I'm probably coming down with something before symptoms show up.

2. You can use their Lifestyle Logging to track how things like caffeine, alcohol, and various nighttime routines affect your sleep. I mean, I haven't discovered anything that's not already common knowledge, but somehow having hard data makes it more compelling. I suppose if I was going to trial any sleep aids then Garmin's correlation would be convenient and save me from having to maintain my own spreadsheet.

3. It alters the suggested workouts if you haven't been sleeping well. Trivial to do manually, but it's a convenient reminder not to overextend.

I track sleep and energy levels with a galaxy watch and there's a strong correlation with how I feel on a given day. Sometimes it surprises me, and day where I wake up thinking I slept well but after an hour or two I'll realize my energy level isn't great, and sure enough I'll check the app and see it's low, with a warning about my sleeping HRV or resting heart rate being away from my norm.

It's not perfect - there are definitely days when it's wrong. But overall I have a target of keeping my sleep and energy scores in the 90s and it's helpful. I think the most important thing is to keep in mind that it's an imperfect measurements but it's still the best one most of us have for now.

Garmin’s body battery is very close to how I physically feel

There are a number of studies comparing these devices with clinical sleep tracking. Just search for sleep tracking on google scholar. My take is that consumer devices have gotten pretty good at detecting when you are sleeping, but are not really good at detecting your sleep phases

Your devices are tracking sleep time, which makes about as much sense as measuring your diet based on how much time you spend chewing.

Time in deep sleep is not a direct marker of slow-wave delta power, which is just one of the measures of repair and glymphatic flush which occurs during deep sleep.

If slow-wave activity is slightly impaired, your brain can try to make up for that reduction by increasing time in deep sleep.

However, larger impairments mean your brain will struggle to stay in deep sleep.

This is why our work at https://affectablesleep.com focuses directly on enhancing the Neural Function of Sleep (and specifically deep sleep) rather than focusing on time.

it's a lot of work, but something you could do is track how you feel (manually or some other way) and do a similar statistical analysis. chess elo was just convenient and aligned for me.

I’m surprised people need this data. Are they not aware if they had a good night sleep? Always had been obvious to me.

by tracking sleep, what exactly do you mean by that? sleep phases, sleep score, sleep duration?

Wrist based sleep tracking is worse than finger.

Oura for measuring sleep. Garmin for tracking physical exercise. Oura always reflected the timings and my feeling much closer than Garmin (Enduro), which basically always told me I had bad sleep (started late after my last woken moments and ended an hour early).

My own thought, it's honestly best not to track sleep unless you feel you have an underlying issue. It causes more anxiety than it solves. If you're tired, go to bed earlier, adjust tech use and food consumption before bed.