3 ms·

Regarding 1: Sleep loss lethality is caused by gut ROS in mice and flies [1] > ...researchers demonstrate in flies and mice that sleep loss leads to an increas

Regarding 1: Sleep loss lethality is caused by gut ROS in mice and flies [1] > ...researchers demonstrate in flies and mice that sleep loss leads to an increase of reactive oxygen species (ROS) in the gut, and that neutralization of ROS can prevent oxidative stress and prolong the lifespan of sleep-deprived flies. Various biological systems seem to have recovery mechanisms associated with the sleep cycles. These cycles are measured using EEG devices but all the major SmartWatch vendors are adding predictive machine learning algorithms to generate the equivalent sleep cycles using optical heart rate data. Continuous sleep cycle tracking might provide crucial insights related to optimal health. [1] https://www.nature.com/articles/s41575-020-0340-6 https://www.nature.com/articles/s41575-020-0340-6

joveian 6y ago
Thanks for the link. Lots of companies have products with claimed effects or measurment of sleep but personally I suspect they are almost always complete BS. I've used a recording pulse oximeter when sleeping a number of times and the pulse seems to reliably predict when I get to sleep but nothing else, not even when I am awake vs. sleeping. IMO, there is no possible way a pulse measurement could replace an EEG. I am also not convinced that sleep tracking would be helpful at all for most people, at least beyond keeping a log with a basic estimate of how much sleep you think you got and how long you were in bed. And even that seems only rarely useful, mostly because I've found it isn't obvious when I've had a month where I slept quite a bit less than usual. So maybe the helpful part is putting it in a spreadsheet and doing some statistics. But for most people I would guess that doing any sleep tracking would cause some disruption and be more harmful than helpful.
- sradman 6y ago
  See Garmin Health Announces Sleep Study Results [1]. I used a Zeo [2] mobile for a few years and I thought I had a good feel for what my sleep cycles tended to look like. I bought a Garmin VivoSmart last Black Friday mostly to try the SpO2 and sleep tracking. I shared your skepticism but, anecdotally, the sleep cycles are as good as what I would get from Zeo. [1] https://www.garmin.com/en-US/blog/health/garmin-health-announces-sleep-study-results/ https://www.garmin.com/en-US/blog/health/garmin-health-annou... [2] https://en.m.wikipedia.org/wiki/Zeo,_Inc https://en.m.wikipedia.org/wiki/Zeo,_Inc.
  - joveian 6y ago
    Hmm... 70% agreement in an unpublished study funded by the company vs a device that is itself maybe 90% agreement with lab PSG. Better than I expected, but I wonder if it is just due to many sleepers having quite predictable stages. "Figure 4 shows the worst result of the cohort (55 of 55), with an accuracy of 49.9%. Note that this user self-reported having a sleep disorder."
    - sradman 6y ago
      > I wonder if it is just due to many sleepers having quite predictable stages That is what I wondered. The Garmin reports my deep sleep in ways that don't match predictable patterns and do approximate times of random events like being woken by animal noises or sirens. Its much better than I expected and I can see it getting much better with the incorporation of additional sensor/external data.
- sradman 6y ago
  I forgot to comment on the following important point: > the pulse seems to reliably predict when I get to sleep but nothing else, not even when I am awake vs. sleeping My experience with the Zeo made me realize that predicting sleep vs wake is hard to do. The modern multi-sensor devices tend to use the accelerometer derived movement together with historical sleep times to predict this. The early Fitbit devices tracked sleep with the motion sensor alone. In the middle of my normal sleep cycles, if I listen to a podcast or read from a smartphone/eReader while remaining mostly motionless, both the Zeo EEG and the Garmin PPG derived EEG will interpret that time as REM sleep. I wonder if the professional sleep labs can accurately detect the difference? The true test will be when sensors/algorithms in casual activity trackers can detect when we nod off or nap during normal waking hours.

joveian 6y ago

Thanks for the link. Lots of companies have products with claimed effects or measurment of sleep but personally I suspect they are almost always complete BS. I've used a recording pulse oximeter when sleeping a number of times and the pulse seems to reliably predict when I get to sleep but nothing else, not even when I am awake vs. sleeping. IMO, there is no possible way a pulse measurement could replace an EEG. I am also not convinced that sleep tracking would be helpful at all for most people, at least beyond keeping a log with a basic estimate of how much sleep you think you got and how long you were in bed. And even that seems only rarely useful, mostly because I've found it isn't obvious when I've had a month where I slept quite a bit less than usual. So maybe the helpful part is putting it in a spreadsheet and doing some statistics. But for most people I would guess that doing any sleep tracking would cause some disruption and be more harmful than helpful.

sradman 6y ago
See Garmin Health Announces Sleep Study Results [1]. I used a Zeo [2] mobile for a few years and I thought I had a good feel for what my sleep cycles tended to look like. I bought a Garmin VivoSmart last Black Friday mostly to try the SpO2 and sleep tracking. I shared your skepticism but, anecdotally, the sleep cycles are as good as what I would get from Zeo. [1] https://www.garmin.com/en-US/blog/health/garmin-health-announces-sleep-study-results/ https://www.garmin.com/en-US/blog/health/garmin-health-annou... [2] https://en.m.wikipedia.org/wiki/Zeo,_Inc https://en.m.wikipedia.org/wiki/Zeo,_Inc.
- joveian 6y ago
  Hmm... 70% agreement in an unpublished study funded by the company vs a device that is itself maybe 90% agreement with lab PSG. Better than I expected, but I wonder if it is just due to many sleepers having quite predictable stages. "Figure 4 shows the worst result of the cohort (55 of 55), with an accuracy of 49.9%. Note that this user self-reported having a sleep disorder."
  - sradman 6y ago
    > I wonder if it is just due to many sleepers having quite predictable stages That is what I wondered. The Garmin reports my deep sleep in ways that don't match predictable patterns and do approximate times of random events like being woken by animal noises or sirens. Its much better than I expected and I can see it getting much better with the incorporation of additional sensor/external data.
sradman 6y ago
I forgot to comment on the following important point: > the pulse seems to reliably predict when I get to sleep but nothing else, not even when I am awake vs. sleeping My experience with the Zeo made me realize that predicting sleep vs wake is hard to do. The modern multi-sensor devices tend to use the accelerometer derived movement together with historical sleep times to predict this. The early Fitbit devices tracked sleep with the motion sensor alone. In the middle of my normal sleep cycles, if I listen to a podcast or read from a smartphone/eReader while remaining mostly motionless, both the Zeo EEG and the Garmin PPG derived EEG will interpret that time as REM sleep. I wonder if the professional sleep labs can accurately detect the difference? The true test will be when sensors/algorithms in casual activity trackers can detect when we nod off or nap during normal waking hours.