Tuesday, February 20, 2018

47 Days Remain: Hypoxic sleeping....in a tent...indoors.

As promised, I am going to take you on a tour of my hypoxic sleeping setup and routine.  Here is my tent:


Inside the tent, I have all the luxuries including a fingertip pulse oximeter (for measuring my spO2 in the morning), an oxygen meter (for measuring the ambient oxygen level), toilet paper (for blowing my constantly running nose throughout the night), heart rate chest strap (for measuring my morning heart rate variability or HRV), Nalgene bottle (to quench my thirst through the night), comfortable pillow, and snacks (for obvious reasons).  All of these items fit snugly along with my upper body in the tent.  

Every night, I go to sleep between 8 and 9pm and plan for at least 8 contiguous hours of sleep.  Well, I say plan because I rarely sleep soundly for 8 hours.  Often, I wake up every other hour to drink some water or pee.  A side note for the latter activity might be necessary to explain how I stay in the tent for at least 8 hours.  Peeing requires a bottle.  I'll leave the gory details to your imagination.

My Hypoxico units sit along the wall in my exercise room (adjacent to my bedroom).  I ran the hoses through the wall so that I could keep the units away from the bedroom and in a cooler location.  Also, these units generate a ton of heat when they run overnight.  Locating them one room away allows me to have a sound night sleep without the additional heat and noise.  Here are the units:


See the hose that runs from the right-most unit?  That hose runs through the wall and into my bedroom.  These units strip the oxygen from the room air and pump that oxygen-depleted air into my tent.  The units have setting numbers that do not correspond exactly to the oxygen percent or any other value that makes sense.  I found that the units could loosely be calibrated by simply tracking the settings and plotting those settings to the observed oxygen percentage inside the tent.  Below is a snapshot of that calibration:


You'll note that the variability of the oxygen percentage varies quite a bit for each setting value.  I noticed this variability the more I observed the correspondence between these two variables.  Perhaps a more interpretable figure is the one that shows the relationship between the unit settings and the simulated oxygen levels (in Feet):


I have a few more setting units left on the scale to go but you can see clearly that my sleeping altitude is now about as high as these Hypoxico machines go.  What do these values mean in terms of my adaptation?  Well....they make it tough on my body for sure.  For those of you with extensive medical training, avert thy eyes.  You might get a shock from some of the numbers.  Fear not!  I am alive and doing quite well.  Here are spO2 values for each of the unit settings:

Yeah, some days are harder than others.  You can see that my spO2 drops with each successive value on the Hypoxico unit.  Over time, however, I tend to acclimatize to the oxygen levels and my spO2 improves.  How much does it improve?  Not enough to keep me out of the emergency room for those who know what these numbers mean.  A healthy person has an spO2 in the upper 90 percent range (I measure about 99% at sea level).  On setting 5 (as indicated in the figure above) using the high altitude adapter on full, I have a median spO2 of about 84%.  Contrast that number with my median spO2 of 71 on setting 6.5 with the adapter on full.   You can see that the response to the oxygen depletion is quite dramatic.  On about the 4th or 5th day of sleeping at each setting, I typically wake up with higher spO2 values and feel great; the first days on each setting can be quite rough.  So I feel an improvement even though I cannot observe that improvement by my spO2 values.  

All of these figures fail to tell the real story.  I need to explain what I am doing.  Here is a snapshot of my hypoxic acclimatization process.  I began my hypoxic sleep training in earnest on January 8th, 2018 by setting my Hypoxico unit to "9" (without the high altitude adapter) and sleeping blissfully for 9 hours.  NOTE:  I actually began sleeping in the tent on July 23rd, 2017 when I returned from a wonderful trip to Ireland.  OK, back to my "earnest" training. Setting 9 resulted in a oxygen concentration in the tent air of 13.6% or an equivalent altitude of 11,100 feet (3383m).  My spO2 in the morning was 88% or good enough to land me into the emergency room for most normal people.  Most of you realize I am not normal so that hospital trip would be a waste.  After about 5 days, I changed the unit setting by 0.5 to simulate a slightly higher altitude.  Each increase leads to a slight decrease in my spO2 (see figure above for some idea about how much change I observe).  

By sleeping every night at a simulated altitude, I increase my red blood cell count and potentially increase the oxygen carrying capacity of those red blood cells (by increasing the hemoglobin).  There are some conflicting views on the effectiveness of this process but I assure the most ardent skeptic that there is no way I could trek to Everest Basecamp in 2 days had it not been for the hypoxic sleep training I did in 2015.

Hopefully these tidbits provided you with some glimpse into one aspect of my training routine - my hypoxic sleep training.  During my next "rest day," I intend to describe some of my gear - starting with my feet.  With 47 days left, I have approximately 11 more full rest days to report on my preparation.  My sinus infection is now gone and I feel great.  With 43 days remaining, you will learn what I plan to wear on my feet.  Each successive post focuses on another part of my body's gear until I end with my head.  So, stay tuned for a foot to head detail of my gear.  

Thanks for following my adventure.