Sleep Apnea: Research and Self-Experimentation Results

 Abstract

I tested several sensors that claim to measure sleep apnea through optical measurement of blood oxygen content.

Background

Blood oxygen arterial saturation (Sa02) is approximated by Sp02.  At 5,000 feet elevation, Sp02 should be above 92%. Values under 90% are considered low.  Hypoxemia is dangerously low blood oxygen, defined as Sp02 <88% for more than 5 minutes.   (Hypoxia is low tissue oxygen levels)

An oxygen saturation level over 95 percent is considered normal. Anything below 92 percent oxygen may be a sign of breathing problems during sleep, such as sleep apnea or another disorder like severe snoring, COPD or asthma.  (Low levels can also be caused by anemia.)

Sleep apnea is characterized by a cessation of airflow lasting 10 seconds or more. Hypopnea (shallow breathing resulting in desaturation) is a decrease in airflow lasting 10 seconds or more with a 30% oxygen reduction and a 3 to 4% desaturation from the baseline. It is not uncommonpatients with sleep apnea to desaturate below 88%. 

Note: low Sp02 is an indicator of sleep apnea and is not necessarily the mechanism of the bad effects.  It may be possible to not have hypoxemia, but still have interrupted sleep.  

Sleep apnea and hypopnea can cause small awakenings that disrupt normal sleep cycles.  This can cause irregular heart beats, high blood pressure, blood sugar excursions, strokes, heart attacks, etc.  Most common effect is to create chronic, elevated stress response.  

Results

- Fitbit Charge 2 never showed any apnea episodes

- Biostrap showed several, including some that my wife didn't remember

- Wellue 02 ring showed several mild episodes per night.  Based on other testing, this sensor seemed potentially the most accurate, but location on finger wasn't comfortable.  Also ended up not being accurate because I sometimes sleep on my arm, cutting off circulation, which reduces Sp02.

Conclusion

I have been diagnosed with mild sleep apnea and my wife has no known apnea.  We both tried the Sp02 wearable sensors and they consistently showed the same level of apneas between us, either none (Fitbit) or mild (Wellue 02 Ring).  Based on the lack of a clear and actionable signal from these sensors, I no longer use them to track apnea events.  Instead I focus on trying to minimize possible breathing issues and promote general good sleep hygiene to try to improve restfulness. 

Covid and evidence for/against the Efficient Market Hypothesis

https://www.bloomberg.com/opinion/articles/2020-06-01/stocks-are-trying-to-forget-2020

Why is the stock market doing so well?

"If in 2019 you built a stock-price model that projected out 100 years of income, you will have to adjust one or two columns for 2020 and 2021, but after that everything can stay exactly the same."

The market movement this year seems to support this simplistic hypothesis and refute "short term-ism" critique of market.

https://www.lesswrong.com/posts/utySCY9nJt9xGYGGQ/the-emh-aten-t-dead

Argues that just because some people could make some money "beating" the market doesn't mean that they didn't get lucky and apply flawed post hoc reasoning.

https://www.lesswrong.com/posts/tonKatiDTzTP8LrEk/zoom-technologies-inc-vs-the-efficient-markets-hypothesis

Argues that EMH needs to be restated, as market predicts the future value of the market, which could be totally "irrational" compared to the real world.

Blood oxygen concentration during Wim Hof breathing

 Here is some interesting data:  Blood oxygen concentration and heart rate during three cycles of Wim Hof hyperventilation and breath holding.

Total elapsed time 14 minutes.  3rd breath hold I went two minutes and bottomed out the blood O2 meter!

Method: 

Followed "Guided Wim Hof Method Breathing" video on Youtube.  

Used Wellue O2 Ring Blood Oxygen Monitor to measure blood oxygen. I tested several wrist spO2 monitors and this finger spO2 monitor is much faster and more accurate. 

HRV "Resonant Frequency" Test

HRV is often used to assess relaxation and recovery, but it is not clear if it correlates with R&R, or somehow causes it.  I think the claim is that it causes it, because HRV is supposed to directly reflect autonomic activity, with higher values indicative of more balanced sympathetic and parasympathetic activity.  (But some recovery scores are calibrated to not let the score get too high all at once.)

But HRV is very susceptible to intentional breathing frequency.  This can be good or bad, depending on whether this manipulation is considered functional or just gaming the system.  

HR naturally slows on the exhale, and speeds up on the inhale, reflecting the dominance of parasympathetic and sympathetic systems, respectively.  By adjusting the frequency of breathing to be resonant with some natural rhythm, HRV can be increased optimally.

I tried breathing rates from 4.5 to 6.5 breaths/minute (at 0.5/bpm steps) and found 5 breaths/minute (=6 seconds in, 6 seconds out) to be optimal for increasing my HRV.  This is my personal optimized meditation breathing frequency for reducing stress.  

HRV is greatest when I take belly and chest breath deep in, then really relax completely on breath out.

Loren Eiseley on Archaeology

"Archaeologists, during the course of their lives, see and hear may strange things, but the fact that they are scientific men keeps them for the most part silent.  They have good, if not superior, rationalizations for the things they do.  No layman would dare impugn their motives.  I, for example, have a certain number of skulls in my possession  As I write I can see four on the shelf above me.  At least two are hidden in my filing cabinet, and there is a beautiful fragment on my desk which is often fondled by visitors who are unaware of its human significance.

Now as it happens I am fortunate.  I practice a trade which enables me to keep these objects about in a perfectly logical and open manner.  I have not murdered to possess them, and if one or two were acquired in dark and musty places, my motives, as I have hinted, are beyond reproach.  As an archaeologist I can be both a good citizen and a frequenter of graveyards."

Human remains and the associated objects reminds me of another passage:

"It struck me that every ruined civilization is, in a sense, the mark of men trying to be human, trying to transcend themselves….none of them has quite made it, but they have each left artifacts. 

The archaeologist, it is said, is a student of the artifact.  That harsh, unlovely word, as sharply angled as a fist ax or a brick, denudes us of human sympathy.  In the eye of the public we loom, I suppose, as slightly befuddled graybeards scavenging in grave heaps.  We caw like crows over a bit of jade or a broken potsherd: we are eternally associated in the public mind with sharp-edged flints and broken statues.  The utter uselessness of the past is somehow magnificently incorporated into our activities. 

No one, I suppose, would believe that an archaeologist is a man who knows where last year’s lace valentines have gone, or that from the surface of rubbish heaps the thin and ghostly essence of things humans keeps rising through the centuries until the plaintive murmur of dead men and women may take precedence at times over the living voice.  A man who has once looked with the archaeological eye will never see quite normally.  He will be wounded by what other men call trifles.  It is possible to refine the sense of time until an old shoe in the bunch grass or a pile of nineteenth-century beer bottles in an abandoned mining town tolls in one’s head like a hall clock.  This is the price one pays for learning to read time from surfaces other than an illuminated dial.  It is the melancholy secret of the artifact, the humanly touched thing."

Quotations are from The Night Country, by Loren Eiseley

OTEC: Ocean Thermal Energy Conversion

OTEC has the potential to harness the power of the ocean, while pumping water from the depths to the surface has challenges and opportunities. It can fuel plankton growth and may help sequester carbon.

1982 National Energy Laboratory Report on OTEC

The xerox scan of the old scientific report is dark and stained, with primitive printing and poor font and layout.  But the columns and official investor report style belie the real science presented, without preamble or typical science summary.

The 1-mile long cold water pipe was deployed successfully in 1981, thanks to "Calm weather and much hard work."  The pipe extends from the surface to 2,000 feet deep. It can pump 500 GPM of deep cold 9-10 C) water. The warm water pipe pumps 2,000 GPM of surface seawater (24-28C).  When allowed to foul freely, it showed immediate increase in resistance to heat transfer, which biofouling countermeasures ameliorated.

The article presents a glowing portrait of research advancing at a fast pace, but is offset with somber photos of cloud-mottled skies and the inclusion of disturbing headings like "biofouling countermeasures". (Biofouling is when nimals get sucked in, and the system can become clogged by marine animals and plants.  This could also be used positively to grow algae) Funding is flowing in from multiple sources like the cold and warm water siphoned from the rich offshore resources...

The project is strategically located with nearby availability of cold, deep ocean water and a warm ocean surface layer that is not subject to strong seasonal cooling. The warm water intake only 15 feet offshore may explain the much more rapid initiation of biofouling than previous experiments.  A 300 foot extension has been designed and was to be installed in 1983.  They plan to add 2 new 500 GPM pumps to replace the original coldwater pump that only pumped from Feb to June at 340 GPM before failing.  They propose reconfiguring the OTEC-1 coldwater pipe to provide a capacity of 22,000 GPM, which would "satisfy their coldwater needs for the foreseeable future."







What ever became of all of this? The Makai Engineering website presents research from the 2010s that seems directly related to work done in the early 1980's, as if a 30 year gap is missing from the story, a lull in research perhaps while people's careers stagnated, limited by something mundane like the size or strength of piping availability or funding.  Maybe the ocean was still there but the money stopped coming from Washington.  Reagon took the solar panels off the white house, and the country went back to sleep for 30 years while a couple of billion people were born and the climate inched toward the 2 degree warming threshold. 

This dark paper seems to hold secrets of the past, arcane mad science experimentation. All that is not said, like the sea creatures sucked up.  So that today when ocean researchers wonder about the effects of cold water outfalls they have to design and bring their own small pipes and pumps.

2008 Reserach: Artifically Induced Upwelling
Used to understand how marine microbial ecosystems respond to large-scale perturbations. Diatoms will consume nitrogen, leaving some amount of phosphorus in the water, which will stimulate a second-stage bloom of nitrogen-fixing cyanobacteria. These blooms are often observed during summer months in open ocean waters when there are almost no nutrients at the surface and the winds generally are calm. What triggers the blooms and where are the nutrients coming from? We need to know.

Vast, seemingly barren regions comprise more than two-thirds of our oceans and nearly 40 percent of the entire Earth.  Need to replace about 10 percent of the surface waters with upwelled water to fuel a bloom.  Some scientists have looked at iron fertilization as a way to trigger biological growth in nutrient-poor areas of the ocean, but “everything responds to iron,” Letelier said. “You can’t control what grows.”

The researchers believe they can control plankton growth by determining which species respond to specific nutrients, and then adjusting the rate of nutrient feeding by the frequency and duration of water pumping.

Where the ocean is about 4,500 meters deep, the bottom layers of water have too much CO2 because of the decaying organisms that have sunk to the floor.  Their studies have shown, however, that water at a depth of 300 to 700 meters has the proper ratio of nitrogen and phosphorus to trigger a two-stage phytoplankton bloom.

Currently, they are able to pump about 50 cubic meters of water per hour (=4 GPM) using wave energy. "If we want to generate a bloom in an area of one-square kilometer, we would need to replace about 10 percent of the surface waters with upwelled water, which would take about a month at the rate we pumped.”

The scientists used undersea gliders in their Hawaii study to monitor the water from the pump so they have an idea how widely and quickly it disperses, and how much of an impact it can have on surface waters.





Resources
List of OTEC plants around the world: https://en.wikipedia.org/wiki/Ocean_thermal_energy_conversion

1982 report about OTEC work at NEL Hawaii: https://nelha.hawaii.gov/wp-content/uploads/2014/01/NELH_AnnRpt_1982.pdf

Upwelling Press Release: https://today.oregonstate.edu/archives/2008/sep/scientists-test-%E2%80%9Cartificial-upwelling%E2%80%9D-learn-more-about-complex-ocean-ecosystem-be

More NEL reports: https://nelha.hawaii.gov/resources/library/

Makai Engineering: https://www.makai.com/ocean-thermal-energy-conversion/

Science Education: What It Takes To Be A Scientist

Motivation: We Are All Scientists Now
Anything can be science...and any detail could be important...(example: Future Perfect Moon Rock episode)

What it takes To Be A Scientist
Attention. You have to care.  Notice something.
Passion. You really get into something. Become an expert. This is more important than grades, social approval, etc.  Do you know what you're talking about?  Be Authentic.
Record.  Journal. Journaling.  Observations, names, dates. Data.
Analyze.  Logic!  Math!
Share.  This used to mean publishing in a journal.  Now it means put it on the cloud somehow: blog, social media, whatever.
Engage.  hang out with other people who share your interest.  This last step can be overwhelming and counterproductive if you skip the other steps.  Don't fit yourself to your group, find a group that fits you! This is part of growing up.

Examples of Things to Notice
shopping: prices
diet: food log
sports: hot hand
environment: observations of birds, insects, plants, plant diseases, mushrooms (need to know names!)
weather: compare forecast to observations

While doing science with humans is possible, the best thing is to get out in nature where there are unlimited questions and more freedom to ask them.  Also, nature is the origin of the traditional sciences, like geology, chemistry, astronomy, biology. 

To teach sciences like chemistry, that can seem abstract, going through discoveries, the exploratory process, alchemy, etc can be helpful. 

Teach science from the basics.  Like how chemistry discovered metallurgy, and how that was made possible by high heat.  Astronomy and biology were made possible by lenses.  Or teach botany by looking at botanical explorers from Textbook of Pharmacognosy by Wallis, T. E. (Thomas Edward).  Another way to make science relevant is by teaching practical applications, like chemistry in baking/washing clothes.

Resources

https://get21stnight.com/2019/12/27/why-introductory-chemistry-is-boring-a-long-term-historical-perspective/

science? example: https://wefunder.com/lppfusion?auto_login_token=cqcK4xYxqbRvcbLm

Questioning is part of science: Socratic Grilling  https://slatestarcodex.com/2020/03/06/socratic-grilling/

Chemistry table of smells: https://jameskennedymonash.wordpress.com/2013/12/30/table-of-organic-compounds-and-their-smells-250-smells/

Responses to Covid19

https://tomaspueyo.medium.com/coronavirus-act-today-or-people-will-die-f4d3d9cd99ca

https://granolashotgun.com/2020/03/10/your-weltschmerz-gives-me-schadenfreude/

https://www.ribbonfarm.com/2020/03/09/plot-economics/

https://slatestarcodex.com/2020/03/02/coronavirus-links-speculation-open-thread/

https://marginalrevolution.com/marginalrevolution/2020/03/emergent-ventures-prize-winners-for-coronavirus-work.html

Ponderosa Mortality After Fire

The best data comes from Hull Sieg, Carolyn, et al. "Best predictors for postfire mortality of ponderosa pine trees in the Intermountain West." Forest Science 52.6 (2006): 718-728.

This graph shows probability of death based on both “crown consumption” (actual burning of the crown) and “crown scorch” (browning of needles due to heat injury). It shows that probability of tree death increases above 50% when Crown Scorch increases past 75%, whereas tree death is above 50% when crown consumption is only 25%. A combination of the two is determined to be the best predictor of tree mortality.

Here are some diagrams of crown scorch and crown consumption. In general, if there are brown needles on the tree that is scorch, if they are black or missing it is consumption.



(from Tree and forest restoration following wildfire by Peter Kolb)

Teachers and What I Learned

This post has been a work in progress since I realized in 2007 that the university couldn't teach me what I needed to learn.  Since then, I've worked on farms and learned ecology from teachers in the field.  But it took me a long time to learn that the real lessons I needed were those that could heal my own body.

Foundation Pose by Eric Goodman - taught me how to load posterior chain, how to bend from the waist. His plank taught me how to activate abs and what neutral spine really means.

Alan Thrall taught me how to deadlift. I went from not being able to do it or hurting myself to lifting regularly.

Brian Mackenzie and Dr. Park taught me to nose breathe during aerobic exercise, and all the time, and that I'm naturally a mouth breather.  Maybe that's why I have sleep apnea.  I never realized it was normal to breath though the nose. 

Diet
Diet gurus, yoga teachers: never taught me anything and may (raw diet) have sent me down the wrong path.  Omnivore's dilemma (eat whole foods, mostly plants) is probably best.  Paul Pitchford has a lot of really deep diet advice, unfortunately it doesn't work for me.  Neither do blood type diets, etc. 


Other Teachers
Headspace app taught me to meditate. But Andrew Weil's 4-7-8 breath works just as well now that I have a few key concepts.

Happy body book by Jerzy Gregorek taught me that relaxing after exercise is as important as muscle tension, and the importance for spine health of hanging (traction) after compression on the spine.

Paval Tsatsouline also teaches that strength is learning to completely tense and then relax muscles.

Getting an inversion table teaches how to stretch spine and soas muscles. 

Slack line teaches balance.  "Gorilla feet" Vibram 5-finger shoes help with balance and teach what is correct shape of the foot.  Altra shoes are also good for this.

I learned a lot in the last 5 years!