Tuesday, January 28, 2014

Pulmonary functioning and high altitude climbing...

Twenty weeks ago, I completed my pulmonary functioning test.  The results were somewhat confusing and I thought I would investigate them further and report back what I found out.  Here are the main findings:
  1. I have asthma - no great surprise but it was nice to get confirmation.
  2. My peak flow is roughly 75% of what it ought to be given my age, body size, and sex.
  3. My lung volume is moderately compromised but not severe enough to warrant too much attention
Why are these results relevant to climbing Mt. Everest?  The most obvious answer is that breathing is essential for life and you cannot climb unless you are alive.  A more subtle and yet obvious answer is that climbing at altitude taxes your breathing.  There is an even subtler answer, however, that requires some explanation.  Bear with me while I go through the mechanisms and then arrive at my final answer.

Some Background

Most of you know the mechanisms of breathing but I figured a quick refresher might help us all understand the same language.  The respiratory system looks like this....

Oxygenated air comes in through the mouth/nose, down the trachea and eventually ends up at the alveolar sacs where oxygen transport takes place.  Experts typically refer to that stage of respiration as "ventilation."  Asthma affects ventilation.  An asthmatic has blocked airways that limit the transportation of oxygenated air into the lungs and exhausted, less-oxygenated air out of the lungs.  All of us living in congested areas know how traffic gets fouled up with just one lane closed; asthma is no different.  We all need to breath and some of us cannot catch a breath when we most need one.  Below is a great picture showing how the blockage occurs with asthma.  

So how do these diagrams relate to high-alpine climbing?  Several ways but I need to provide a bit more detail.  Consider the full oxygen transport cascade depicted in the figure below.

The x-axis in the figure above shows the cascade (stages) from inspiration to the final delivery to the blood (Venous).  The y-axis in the figure represents how much oxygen is available at each stage.  Asthma affects the first stage by limiting inspiration  (really by limiting expiration) and also the second stage by restricting airflow to the alveoli.  Each of these limitations leads to bad outcomes.  Here is how....

Breathing at high altitude

Here is what we know about the affects of high altitude.
  1. Altitude reduces the percent of oxygen in the atmospheric air (pre-stage 1).
  2. Reduced oxygen in the air means that inspired air has less oxygen to be absorbed.
  3. The reduced oxygen and consequently the increase in CO2 in the air causes the carotid bodies to signal the body to breath more frequently (i.e., increased respiration rate).
  4. Increased respiration rates are generally good BUT the increased rate leads to a greater expiration of CO2  and that results in a higher blood pH (more alkaline) - two bad outcomes.
  5. Higher blood pH - a situation call blood alkalosis - is not fatal but it does compromise your body's ability to function properly.  More importantly....
  6. Lower CO2 concentration in the blood REDUCES your breathing rate.  While this last consequence seems less problematic than the blood pH, I came to realize that this outcome is the part that causes the greatest problem for mountaineers.  
Breathing is essential - as we all know - but breathing is what helps us acclimatize to high altitude environments.  As your respiration rate decreases, your chances of HAPE (High Altitude Pulmonary Edema) and HACE (High Altitude Cerebral Edema) increase.  Both HAPE and HACE end your climb immediately.


Now, back to asthma.  How does asthma affect your ability to acclimatize?  Asthma, as my brother explained to me, is a disease that affects expiration mostly.  Yes, it does affect inspiration but it is the expiration that is the greatest concern.  If an asthmatic person is less able to expire air then that person's body does not expel CO2 as rapidly as a person without asthma.  Sounds like a good situation, right?  Well, not exactly.  If you cannot expel the residual air from your lungs, you are less able to inhale new, oxygenated air.  Thus, asthmatics are less likely to function well at altitude than non-asthmatics because of an air exchange problem.  Less air out means less air in and if that air is already oxygen compromised then the little you take in creates an even bigger problem for the oxygen starved body.

Is asthma a big deal in mountaineering?  Simply put - YES.  Cold dry air often triggers asthma attacks.  There is little moisture in high altitude air and the temperature is pretty obvious.  Combined, the cold and dry air inhibits the exhalation of air from the lungs (good if you are only concerned about alkalosis) and increases the CO2 concentration in the blood.  Why?  Asthmatics cannot expel the CO2 rich air after the respiratory process.  To make matters worse, the increased CO2 leads to a higher respiration rate but a rate that is not beneficial to the asthmatic because the air that now comes in at a faster rate is also cold and dry.  The picture gets really simple.  Imagine having a drink of water from a hose.  If the hose offers you a trickle and you can use that trickle of water to slake your thirst then you come away from the experience satisfied.  What happens when the hose is attached to a fire hydrant?  That hose no longer provides the refreshments you desire.  Instead, you drown.

Asthma is akin to drowning because the failure to exchange oxygen depleted air with oxygen rich air leads to suffocation - much like drowning.  The greater the limits on this exchange, the greater the likelihood of HAPE or HACE.  

So what do I do about my asthma?  Manage it prior to, during, and after climbing via sound judgement, modest use of drugs (prescription not recreational), and preparation.  I had an asthma attack on Denali upon my descent from the summit and it was hardly a fun experience.  Rarely have I been so affected by asthma.  I am taking every step possible to avoid that situation on Everest.  Thanks to my brother and his colleagues at Allergy Partners, I am a well-managed asthmatic.  

Week 33 Update: Food, diets, fatigue, bonking, and recovery - they all go together.

Week 32 Update: Jan 28, 2014 for the week beginning on January 12th, 2014

A great week all around with a few important observations….

  • Sleep might help me recover but food helps me stay focused and press through the hard workouts. I bonked on Sunday and was reminded of my friend Spencer who once bonked on a bike ride with a friend. If I recall correctly, they both bonked a good distance from home and were later rescued by Spencer's wife Stephanie. She found them sitting on the side of the road eating onion grass. That image remains with me after 20+ years and I am sure it remains with both Spencer and Stephanie. Well, Sunday brought me to the point of exhaustion but only because I did a horrible job eating prior to my training. Note to self: eating is important for endurance. No onion grass feed-fests for me!
  • Gave another talk at the local (DC) Quantified Self meetup. They are a great group and, if you are in the area, I highly recommend going to the meetings. Heck, if you are not from around the DC metro area, find a local group. Nothing like getting a bunch of highly motivated, educated and dedicated folks together to solve problems via self-monitoring and data analysis. My kind of group! Thanks to all of you from QS.

Workout Progress

“Summit Sundays” - for this week, it was “Summit Monday” - continue without a hitch. Well, actually that depends upon who you ask. These long days might be productive for my preparation but they are a huge distraction to my family life. I decided this week to wake up really early so I could be done before 3pm. We already get up early enough during the week so my one day to really sleep in must go away for my family's sake. It (sleep) is a reasonable sacrifice and one I gladly make to have time with my wife and son.

plot of chunk WeekEx

I continue to recover reasonably well from these long days. Last week was 8.75 hours and I felt OK the next day. The hardest part is going back to work and having to adapt to a new schedule. Change ain't easy.

plot of chunk DailyWL

I cannot believe I am almost half-way through my last phase. Time is running out and I am almost completely mentally prepared to head out to the mountains. I still have a few more weeks left and some more mental/physical/equipment preparation left.

plot of chunk CumWL

Weekly Summary

Food, food, food, food, and more food. I decided to forgo any plans to eat healthy at this point. The food while climbing will consist of a smorgasborg of culinary catastrophies that I need to be used to before I leave. This past week convinced me that I need to be more flexible in my diet. Eat everything and anything at any time to refuel.


Now that I am back to work and teaching my usual 2-course load, I have a bit more stress but, surprisingly I am more productive. Amazing how a more packed schedule results in a greater focus and less wasted time.

plot of chunk Mood

Hypoxic Training

I trained last week at 17,800 feet for all my sessions in the house. The remainder of my training was higher intensity (swimming and running sessions) to maintain my lactate threshold and anaerobic fitness. I think this combination works well for both fitness and recovery. Only my time on the moutain will confirm my suspicion but now I think I am adapting well to hypoxia. Note the subtle but real decline in morning spO2 levels? Kathy and I both experienced the same dip one the same days. I wonder why. We have completely different training regimes. My suspicion is that the two of us consume the same pool of air in the tent. When one of us struggles, the other struggles as a result of the changing ambient air conditions (i.e., more CO2 and less O2). I plan to look into this observation further.

plot of chunk Hypoxia

Recovery (Restwise Data)

As I said in my introduction, sleep might be king but food is equal parts royalty during training. I am still recovering reasonably well and continue to gain some extra weight - not much but enough to readily lose without looking like a skeleton upon my return.

plot of chunk RestwiseData

Updates for the week

Now that I am back to work, I am reminded how important my students are for my morale. The students in my lab, in my classes, and who just swing by for a quick chat give me a great sense of pleasure. Thanks to all of you.

I have a few other blog posts and a few that remain unfinished. Expect a bit more posting in the near future. These posts, in no particular order are…

  • Hypoxic adaptation and asthma
  • Elitism in sports - a common problem but one worth discussing
  • The (in)complete guide to preparing for the extremes. I want to follow-up with one of Alan Arnette's posts about the complexity of training/preparing for Everest. He is a wonderful writer and a first-class thinker about the topic. I strongly encourage you to read his blog (click here). Alan documents the Everest expeditions each year. His blog (and hopefully mine) serves as a great resource for the most up-to-date Everest information. Thanks Alan for posting my blog link on your page. Go visit Alan's page and please donate to his causes.