Category Archives: Altitude Science

The Plants We Need Are There: A Naturopathic Approach to Acute Mountain Sickness

Acetazolamide is already known for its success with treating Acute Mountain Sickness (AMS) and helping patients with their transition to higher altitudes, but what other options are available? What about those who don’t want a prescription, that are looking for other alternatives to help them with AMS and being at high altitude?

During my time in Frisco, Colorado (9000’/2743 m) I was fortunate enough to interview two resident Naturopathic Doctors. Mountain River Naturopathic Clinic on Main Street of this little mountain town is a wonderful oasis for anyone in Colorado’s Summit County looking for alternative care and treatment for their mind and body.

Dr. Kimberly Nearpass, ND and Dr. Justin Pollack, ND took the time to educate Dr. Chris Ebert-Santos, my classmate Rachel Mader, and myself about all the naturopathic remedies available for AMS and residents at altitude.

Tell us about Naturopathic medicine and why you picked this path of medicine?

Dr. Kimberly Nearpass: I thought I was going to be an OBGYN and then I did more research. I talked to doctors, midwives and herbalists and found that the Western medicine model didn’t feel right to me. So I thought, “Do I go to medical school and try to operate functionally from the inside or do I find another track?” I did not know about naturopathic medicine until a few years later. I took some time off; I traveled and went to the Peace Corps and then I discovered naturopathic medicine and loved it. I had lived in Ecuador in the rainforest as a naturalist guide so I learned a lot about traditional medicine that way. I learned a lot about traditional medicine when I lived in rural Africa as well. Living in these rural areas and watching the indigenous people — and they certainly use modern medicine — but they did not have a lot of access. Especially in the rainforest, they were using a lot of plants and I was fascinated by that. But I still wanted the medical training. Then I discovered naturopathic school. So, it’s four years of medical school, we get the medical training, but we also have that more holistic, natural, herbal based approach.

What naturopathic remedies are available for acute mountain sickness (AMS)?

Dr. Nearpass: So I will tell you Acli-Mate is our go-to. I’m not tied to this product, a friend of mine, it is her company, she is a naturopathic doctor in Gunnison. She formulated this, she started it out as a high-altitude electrolyte drink. Everybody that comes in our door, we start with this. This stuff works AMAZING. We rarely have to go anywhere else. I think the combination of the electrolytes and that it is hydrating has a great benefit. It helps with the headache and the nausea. For mild to moderate symptoms of AMS it is incredible. What we do is if we have family coming to visit from sea level is we have them start drinking it before they come.

Acli-Mate is found to be highly effective at helping people who are suffering from AMS. The blend includes herbs Ginkgo biloba and Rhodiola, both of which have proven effective in preventing and treating altitude related sickness. Both herbs seem to improve circulation, especially through cerebral vessels, and cellular energy function through improved uptake and utilization of oxygen, reducing toxic brain edema. Ginkgo has also been shown to inhibit platelet clumping, keeping red blood cells evenly dispersed, which improves delivery of oxygen to tissues, while Rhodiola appears to help the body deal with stress.

Nutrients in Acli-Mate: Vitamin C, and many of the B vitamins: thiamin (B1), riboflavin (B2), niacin (B3), pantothene (B5) and cobolamin (B12).

Acli-Mate in a variety of applications.

Have you noticed that when you have patients drink it before they arrive at high altitude, they have a better outcome?

Dr. Nearpass: Yes. And I have a patient who is 70 now and 5-10 years ago she went with some girlfriend to hike Mount Kilimanjaro. She had all her girlfriends take it and emailed me after saying, “We all did great!” And I don’t want to put all my eggs in one basket but this is almost always all we need.

Dr. Justin Pollack: There is something about that blend of Rhodiola, Ginkgo and the B vitamins that seems to work. We’ve had tons of people use it clinically.

Dr. Nearpass: For other options, I think Rhodiola is a good one. It’s interesting to me because Rhodiola grows in Mongolia, it grows in high altitude. One of the things we talk about in herbal medicine is often the plants we need are there. For example, dandelion root grows everywhere and it is good for liver detox and helps with hepatic function. So, it is interesting to me that dandelion is popping up on the side of the highways and in areas that we could probably use a little cleansing and detoxing.

Dr. Chris Ebert-Santos: What about Coca?

Dr. Nearpass: Oh yes! Coca works amazing. It is a plant that grows in the high altitudes of South America and when I was living in Ecuador the folks that live in the Andes drink coca tea all the time. They also take coca leaves and shove a wad in their mouth like chew. While they are doing work, cardiovascular work, they just put it in their mouth and that is their medicine. It gives them more stamina and reduces fatigue. There is not much research on it because you cannot even get it in the states.

Is there a reason you can’t get it here?

Dr. Nearpass: Because it’s the same plant as cocaine. We used to have a homeopathic version of it. Do you know what homeopathic medicine is? You take a remedy and you dilute it until you don’t have any molecules of the original substance but you basically are getting an energetic imprint. For example, Rhus tox, poison ivy, the homeopathic rhus tox is used to treat red itchy inflamed poison ivy type symptoms. But with coca, even homeopathically, the herb is used in concentrated doses to treat high altitude sickness and increase energy and stamina. But because there is such a control over coca, we can’t even get the homeopathic version, which is ridiculous because there is not a single molecule of the plant in the remedy.

Dr. Pollack: When Kim and I were on our honeymoon, we passed through Bolivia and Peru. In Bolivia in la Paz there was a coca museum. It was really fascinating because something around 1,000lbs of coca leaves must be distilled down into 1 gram to make cocaine. When you make tea out of the raw leaves it seems to have the subtle effect of suppressing appetite and allowing people to do better at altitude. Marijuana has a whole stigma around it, even though it has been legalized, and so the research and researchers are stigmatized, yet there are a lot of useful compound coming out of the plant. So, I’m sure that coca is the same, and hopefully somewhere down the line we will be able to use coca leaf for altitude.

Dr. Nearpass: And certainly, coca is the number one herb in the Andes that people use. You can get it everywhere, it’s like black tea down there.

So because coca is not available for your patients, and if you found Acli-Mate was not successful, what would you recommend?

Dr. Nearpass, a woman in a white hoodie, long brunette hair, and a maroon mask, stands in front of a wall of shelves of naturopathic medicine in brown glass jars with black lids at the Backcountry Apothecary in Frisco, CO.
Dr. Kimberly Nearpass

Dr. Nearpass: This is the thing about naturopathic doctors, we look at each individual. If it’s a resident, per se, we are going to draw blood work. We are going to try to figure out what’s going on, what is the underlying issue. Do you have relative anemia? We will run iron but also ferritin. They may have normal blood cells, normal H&H but their ferritin is a 2. One of the things that is tricky about being a naturopathic doctor is, we will be at a party and someone will ask, “Well what do you do for hypertension?” or “What do you do for digestive issues?” We always say we don’t treat symptoms; we don’t treat disease, we treat people. If someone is having recurrent altitude sickness, we are going to look at the individual and look at what is going on. What’s their diet? Are they hydrated enough? Are they drinking too much alcohol? Do they have subclinical hypothyroidism that might affect their metabolism and their ability to adapt when they get here? Might their ferritin levels be really low? And then we would sit down with the patient and say, “Well what are your symptoms? Is nausea the main symptom? Is headache the main symptom?”  And then, what other factors could be contributing to these symptoms? If it’s headache then CoQ10 would be what I would go to.

Dr. Chris Ebert-Santos: And what do you look for on physical exams on residents that are having trouble with altitude?

Dr. Nearpass: On physical exams we are doing the standard physical that you would do but we are also looking at the tongue. I am not a Chinese Medicine doctor but the tongue does give you some insight on what is going on in the digestive tract. If we are seeing inflammation or glossitis or geographic tongue, we are thinking, “Oh, this person may have some underlying digestive issue.” We might look at Arroyo’s sign, it’s a traditional sign when you shine a light on someone’s pupil and most of the time their pupil will constrict, but Arroyo’s sign is both pupils will stay dilated. This is a red light for adrenal issues, for hyper cortisol output or adrenaline output. If someone is in a chronically stressed state, their pupils are going to be dilated all the time. If it looks like someone has chronic stress, it takes you out of the parasympathetic, and so their digestion is going to be weaker. The way we look at it is the body has to prioritize, and there is only so much that one body can do. And I suspect that living at high altitude puts chronic stress on the body. I see this huge lack of libido in the women. I see women in their 20s, 30s, 40s, 50s. But it kind of makes sense right? If the body is chronically stressed, having a baby is a huge energy output for a woman. So, I think we may see the chronic stress impacts of living at high altitude.

Dr. Chris Ebert-Santos: So what do you do for the libido?

Dr. Nearpass: That is one that if I could invent one pill, it would be that one. Libido is really hard, especially in women. Unfortunately, what I see is its one of the first things to go in women and it’s one of the last things to respond. So, my suspicion is that this altitude is another physical stress on our bodies. I think we can see multiple systems being affected by it, maybe not severely but still.

Rachel Mader PA-S: Is there anything for sleep at altitude? I know a lot of people struggle with that.

Dr. Nearpass: Yes, again for us there is no magic bullet. Melatonin is very well known and that can be very helpful for some people, but it sure doesn’t work for everybody.  When patients come in and say, “What do you use for sleep?” I want to take every person back and have a conversation with them. Ask, “Are you having a hard time falling asleep? Are you having a hard time staying asleep? Are you waking up to go to the bathroom?” Right? So, there isn’t a magic bullet that will work for everyone. Breaking it down, I think you could have 50 people with altitude sickness and we’re going to do 50 different things. I mean, I would start with Acli-Mate, but every patient will be different.

Do you think there’s benefit to adding Acli-Mate in combination with an Acetazolamide prescription?

Dr. Nearpass: As far as I know, there’s no issue combining the two. Most people that come to us are usually trying to avoid medication, but what I always say to them in that situation is, “Try this other stuff to see if it helps.” But if it’s someone who had trouble in the past with AMS, I’ll say go to your medical doctor and get the prescription so that you have it if you need it. I think another issue is that people fly here right from Texas. They fly to Denver, they get right on the shuttle, and they drive right up here. If they’ve had trouble in the past, they should drive here and take their time. Spend a couple days in Denver if they have to. That does seem to help people.

Thank you so much Dr. Nearpass. Is there anything else about naturopathic medicine and high altitude you would like to share with us?

Dr. Nearpass: I guess I would say again that from a naturopathic perspective it is really about looking at the individual.

Is there anything that could specifically help with nausea symptoms of AMS?

Dr. Nearpass: Ipecacuanha! Ipecac syrup — which in full doses will make you throw up, so the homeopathic Ipecacuanha we use for nausea — that is one I have actually used quite a bit for people who have that aspect of AMS. It is really good for nausea and pregnancy too.

PA student Hannah Addison with Dr. Pollock, Dr. Nearpass and Dr. Chris in front of the Naturopathic clinic and apothecary in Frisco, CO.

The way I see Healthcare is a full spectrum, and on one end you have the brain surgeons and on the other end you have the Reiki energy healers. Then you have everything in between. I see us sitting in the middle. For patients, the best thing is to be aware of where they belong on that spectrum. I’m not going to replace a brain surgeon, but sometimes a little bit of massage and energy can do the trick. It is so great for us as practitioners to be able to talk and converse with the medical doctors. We’ve been really lucky in this community.

Visit Mountain River Naturopathic Clinic’s website or stop by their shop and clinic: http://www.mountainriverclinic.com

Available research articles on Naturopathic Remedies and AMS:

Zhang DX, Zhang YK, Nie HJ, Zhang RJ, Cui JH, Cheng Y, Wang YH, Xiao ZH, Liu JY, Wang H. [Protective effects of new compound codonopsis tablets against acute mountain sickness]. Zhongguo Ying Yong Sheng Li Xue Za Zhi. 2010 May;26(2):148-52. Chinese. PMID: 20684264.

Tsai TY, Wang SH, Lee YK, Su YC. Ginkgo biloba extract for prevention of acute mountain sickness: a systematic review and meta-analysis of randomized controlled trials. BMJ Open. 2018;8(8):e022005. Published 2018 Aug 17. doi:10.1136/bmjopen-2018-022005

Gertsch JH, Basnyat B, Johnson EW, Onopa J, Holck PS. Randomised, double blind, placebo-controlled comparison of ginkgo biloba and acetazolamide for prevention of acute mountain sickness among Himalayan trekkers: the prevention of high-altitude illness trial (PHAIT). BMJ. 2004;328(7443):797. doi:10.1136/bmj.38043.501690.7C

Ke T, Wang J, Swenson ER, et al. Effect of acetazolamide and gingko biloba on the human pulmonary vascular response to an acute altitude ascent. High Alt Med Biol. 2013;14(2):162-167. doi:10.1089/ham.2012.1099

Wang J, Xiong X, Xing Y, et al. Chinese herbal medicine for acute mountain sickness: a systematic review of randomized controlled trials. Evid Based Complement Alternat Med. 2013;2013:732562. doi:10.1155/2013/732562

Lee SY, Li MH, Shi LS, Chu H, Ho CW, Chang TC. Rhodiola crenulata Extract Alleviates Hypoxic Pulmonary Edema in Rats. Evid Based Complement Alternat Med. 2013;2013:718739. doi:10.1155/2013/718739

Hannah Addison, PA-S

Hannah Addison (she, her, hers) is a second-year physician assistant student at Red Rocks Community College Physician Assistant Program in Arvada Colorado. Hannah was born and raised in the South Denver area of Colorado. She spent four years getting her bachelor’s in biomedical science at Colorado State University in Fort Collins, CO where she decided her life career goal was to become a PA. After graduating and while applying for PA programs, Hannah worked at Littleton Adventist Hospital of Centura as a CNA, Telemetry Technician and Unit Clerk. In her free time, Hannah enjoys hiking and discovering all the delicious food and drink Colorado has to offer.

Facing the COVID-19 Pandemic in the Mountains During the Winter

Ski resorts have opened in Colorado, and with more holidays around the corner, it is essential to remember that we are still currently amid a pandemic that is surging with cases here in Colorado. So what does that mean for those that live in the mountains and at altitude?

When it comes to the coronavirus, there are advantages and disadvantages to living at altitude. While research does show that COVID-19 has a more challenging time affecting mountainous populations, Summit County, Colorado has its own set of dangers. With the influx of skiers, travelers, and increased indoor activities, it is essential to remember how to protect yourself and your neighbors here in Summit. 

Research shows that populations living at higher altitudes are at less risk of transmission and have better adaptations to hypoxia than those living at lower altitudes (Pun et al., 2020). Interestingly, people living in high altitude environments live in a state of hypoxia or lower oxygen levels, and the lungs of these people generally adapt to conditions of decreased oxygenation. However, this has not been proven to be a saving grace, especially if the person has comorbidities like asthma, hypertension, diabetes, kidney disease, or COPD. Research has also shown that the environment is often colder and drier at higher altitudes with increased UV radiation, which can help slow the spread of the virus. However, this is only relevant when you are outside and does not diminish its spread indoors. While all these facts are unique to living at altitude, we must remember that Summit County is a tourist destination, is densely populated and requires the utmost protection despite these factors. 

So how do you protect yourself this upcoming winter in the mountains? With ski resorts initiating strict policies and physical distancing, what are ways that we can help keep these businesses and resorts open?

Some might blame the tourist for bringing COVID to the mountains; however, the increase in numbers can be tracked down to Summit County residents spreading it to one another through social events and large gatherings. It is important to remember to wear a mask, stay at home whenever possible, wash your hands if you feel sick, get tested, isolate, and make sure to get your flu shot.  It is essential to listen to public health orders as they change throughout this second surge of COVID-19 infections. Going into the holidays, the CDC recommends not traveling to see your family and only celebrating the holidays with family members that live in your house. It is essential to stay vigilant as we go into the winter months so the mountain communities can stay safe. 

COVID-19 Information 

What are the symptoms of COVID-19?

  • Fever
  • Cough
  • Body Aches
  • Chills
  • Shortness of Breath
  • Headache
  • Loss of taste or smell
  • Congestion
  • Sore Throat
  • Nausea/Vomiting
  • Diarrhea

When do I seek emergency help?

  • Trouble breathing
  • Pain or pressure in chest
  • Inability to stay awake or awaken
  • Blue colored lips or face
  • New confusion

Where do I get tested in Summit County?

  • Community Testing Site
    • Where: 110 Third Ave. Frisco, Colorado
    • When: 8 a.m.-5 p.m. Monday through Friday
    • Who: Asymptomatic and symptomatic individuals
    • How: email summitcovidtesting@vailhealth.org with the information below –
      • Name
      • Phone Number
      • Picture of Photo ID (not necessary if you don’t have one)
      • Front/Back pictures of insurance card (not necessary if you don’t have one)
  • Centura Health Community Testing Site
    • Where: Summit Vista Professional Building 18 School Rd. Frisco, Colorado
    • When: 9 a.m.- 2 p.m. Monday-Friday & 9 a.m.- 12 p.m. Saturday-Sunday
    • Who: Asymptomatic and symptomatic individuals
    • How: Call 970-668-5584 to receive testing referral. 
  • Summit Community Care Clinic
    • Where 360 Peak One Dr., Frisco, Colorado, First Floor, Summit County Medical Office Building, Suite #100.
    • When: Tuesday, Wednesday, Friday during business hours
    • Who: SCCC patients or establish care with SCCC
    • How: Call 970-668-4040 to schedule an appointment
  • Mako Medical Community Testing Site
    • Where: Silverthorne Recreation Center overflow parking lot, 464-478 E Fourth St., Silverthorne, CO 804898.
    • Who: Asymptomatic and symptomatic
    • How: No appointment necessary, will need to complete registration at site or before online. 

Summit County updated testing information: https://summitcountyco.gov/1324/Testing

Caitlin Endly is a Texas transplant that has lived in Denver, Colorado for the past three years going to school to become a Family Nurse Practitioner at the University of Colorado. She has been a Registered Nurse for five years and currently works as a Neuro Trauma nurse at St. Anthony’s Hospital in Denver. She graduated with her Bachelor’s of Science in Nursing from Texas State in San Marcos, Texas and has worked as a neuroscience nurse since graduating. In her free time she likes to dance, snowboard, and listen to live music. 

Your Baby or Child Is On Oxygen

This is a handout distributed by Dr. Christine Ebert-Santos, MD, MPS, at Ebert Family Clinic, Frisco, Colorado.

Living at high altitude is a challenge for our bodies. The amount of oxygen in the air we breathe is less the higher you go. Since we all need oxygen to live, this can cause problems.

There are three times when oxygen may be needed by children living at altitude:

  1. During the newborn period;
  2. When a child has a respiratory illness, even a mild cold;
  3. During the first 48 hours after returning/arriving from sea level.

When a baby takes their first breath, the higher oxygen level in the air sets off many changes in the heart, lungs and blood vessels around the lungs that convert the child’s respiratory system from transferring oxygen from the placenta to the lungs. Exposure to a low oxygen environment during the first few weeks can interfere with the normal fall in the pressures of the blood vessels in the lungs and closing of the vessels that shunted blood away from the lungs in the womb.

In babies and children, we are not worried about brain damage from lack of oxygen due to the altitude. Don’t panic if the oxygen cannula falls off during the night or the tank runs out. The problems caused by the low oxygen saturations (usually running between 78 – 88%) seen at altitude develop over days, weeks or years, due to changes in the heart and lung. Hypoxia, the term for low oxygen in the blood, causes constriction, or narrowing, of the blood vessels in the lungs. This can lead to back pressure on the lungs and heart, which may cause fluid to leak into the air sacs in the short term or abnormal increases in the heart muscle in the long ter.

Rarely do babies or children with low oxygen levels at altitude show symptoms. The normal oxygen saturation levels at 9000′ are about 92 – 93%, and can be 89 – 90% in healthy people. We start treating with oxygen below 89%, even though symptoms like trouble breathing, fast breathing, poor sleep, or poor color are unusual until the saturation level is in the 70’s.

It is important to understand that oxygen is prescribed by your doctor to treat symptoms of altitude sickness such as headache, vomiting and trouble breathing, and to prevent more severe symptoms from developing. A small percent of persons with mildly low oxygen levels will suddenly, over a few hours, go into full-blown pulmonary edema where their lungs fill with fluid, they have much more trouble breathing, and turn blue. This is a life threatening emergency.

When you arrive home with your child on oxygen, be sure and call the respiratory therapist at the phone number on the tank so they can come to your house and teach you about the equipment. Don’t feel discouraged if your toddler or young child is fighting the oxygen at first. They will usually adjust and accept the cannula in about 30 minutes.

Acetazolamide

Typical symptoms of acute mountain sickness (AMS) are headache, loss of appetite, disturbed sleep, nausea, vomiting, fatigue, and dizziness. However, more serious conditions such as high altitude pulmonary edema (HAPE) or cerebral edema (HACE) can present with this illness. Avoiding these unpleasant symptoms while at elevatione is possible through gradual pre-acclimatization when possible (what science recommends!), or there are specific medications that can potentially prevent the development of AMS, such as acetazolamide. This article will address how acetazolamide (also known as Diamox) can help prevent AMS, discuss the physiological effects of the medication, some side effects, and whether or not this drug can enhance physical performance.

 How does it work?

Acetazolamide is a carbonic anhydrase inhibitor. Carbonic anhydrase regulates kidney absorption of sodium bicarb and chloride. Acetazolamide works by inhibiting carbonic anhydrase, preventing the reabsorption of sodium bicarb and chloride, causing acidosis in the blood. When experiencing AMS, the body is in a state of respiratory alkalosis. By taking acetazolamide, which causes metabolic acidosis it drives receptors in the body to increase the patient’s minute ventilation by as much as 50%, improving arterial PO2 and increasing oxygen saturation.

How can I obtain acetazolamide and when should I start taking it?

Acetazolamide requires a doctor’s prescription, and the typical dose for the prevention of AMS is 125 mg twice daily. The typical recommendation is to start taking acetazolamide one day before your exposure to high altitude and continue usage throughout your trip. When taken one day before exposure, studies show that acetazolamide reduced AMS incidence and enhanced tolerance to submaximal exercise on the first day at high altitude versus starting administration the day of arrival.2 However, if, for some reason, the medication isn’t started a day before arrival to high altitude, then the medication should be started upon arrival, which still shows a decreased incidence in the development of AMS. 

Allergies & Side Effects

Acetazolamide belongs to a classification of drugs known as sulfonamides, which is broken down further into two categories: antibiotics and nonantibiotics. Acetazolamide is considered a nonantibiotic sulfonamide, which varies significantly from sulfonamide antibiotics because these antibiotics contain what is known as an arylamine group in their chemical structure. This arylamine group is a key component of the allergic response to sulfonamide antibiotics (sulfamethoxazole, sulfasalazine, sulfadiazine, and the anti-retrovirals amprenavir and fosamprenavir); however, this structure is not present in other sulfonamide drugs like acetazolamide.1 There is available evidence that suggests patients who are allergic to arylamine sulfonamides do not cross-react to sulfonamides that lack the arylamine group and so may safely take non-arylamine sulfonamides.1 Patients with known allergies to sulfonamide drugs should consult with their healthcare provider before taking acetazolamide.

Like all other medications, there are risks that side effects will occur with acetazolamide’s administration. The common side effects are fatigue, malaise, changes in taste, paresthesia, diarrhea, electrolyte disorders, polyuria, and tinnitus. While conducting research, I found 3 – 4 people from my hometown, located at 69 feet above sea level, who have taken acetazolamide while rapidly ascending to 8,000+ feet to ski or hunt. When asked how their experience was taking acetazolamide, the common response was that they stopped using it within the first two days due to the change in the taste of their beer! The pleasurable “fizz” in our carbonated drinks is attributed to chemical excitation of nociceptors in the oral cavity via the conversion of CO2 to the carbonic acid in a reaction catalyzed by carbonic anhydrase. So administering a carbonic anhydrase inhibitor like acetazolamide results in flat-tasting carbonated drinks, or, as described by the aforementioned subjects, a “nasty beer”!4 While a bad tasting beer is no fun, AMS is a lot less fun, and one would be best advised to continue taking acetazolamide while at high altitude.

Can taking acetazolamide increase physical performance and endurance at high altitudes?

Though enticing, it doesn’t seem to work out that way. There are multiple studies on exercise endurance in hypoxic conditions with the administration of acetazolamide, but the produced results are confounding. The majority of the studies show that for a non-acclimated person taking acetazolamide in hypoxic conditions, endurance and exhaustion time were increased with submaximal and maximal exercise. A few reasons this may be true are the induction of metabolic acidosis and its effects on muscle cells, the diuretic effect of the drug inducing dehydration, and additional increases in work of breathing cause vasoconstriction in locomotor muscles, which can impair exercise performance.3 Regardless, this medication’s proven science in the prevention of AMS should not be mistaken with the multiple confounding studies on exercise endurance.

Scott “Scotty B” Rogers, FNP-S

From Opelousas, Louisiana, Scott Rogers is currently a Family Nurse Practitioner student at Walden University after having practiced five years as an RN following his BSN from the University of Louisiana at Lafayette. He has lived in Colorado for the past four years where he enjoys hiking with his wife and dog, snowboarding all the resorts in Summit County, and basketball, and hopes to pursue more work with acute physical rehabilitation, orthopedics, and sports medicine.

References

1. American Academy of Allergy Asthma & Immunology. (2019, June 23). Acetazolamide and sulfonamide allergy: AAAAI. Retrieved November 13, 2020, from https://www.aaaai.org/ask-the-expert/acetazolamide

2. Burtscher, M., Gatterer, H., Faulhaber, M., & Burtscher, J. (2014). Acetazolamide pre-treatment before ascending to high altitudes: when to start?. International journal of clinical and experimental medicine, 7(11), 4378–4383.

3. Garske, L., Medicine, 1., Brown, M., Morrison, S., Y, B., G., B., . . . Zoll, J. (2003, March 01). Acetazolamide reduces exercise capacity and increases leg fatigue under hypoxic conditions. Retrieved November 13, 2020, from https://journals.physiology.org/doi/full/10.1152/japplphysiol.00746.2001

4. Jean-Marc Dessirier, Christopher T. Simons, Mirela Iodi Carstens, Michael O’Mahony, E. Carstens, Psychophysical and Neurobiological Evidence that the Oral Sensation Elicited by Carbonated Water is of Chemogenic Origin, Chemical Senses, Volume 25, Issue 3, June 2000, Pages 277–284, https://doi.org/10.1093/chemse/25.3.277

A conversation with Dr. Chris on neonatal oxygen levels at elevations 9000’ and above

My name is Austin Ethridge, I am a physician assistant student from Red Rocks Community College PA program who has been fortunate enough to have completed my pediatric rotation with Dr. Chris in Frisco, Colorado, this month. Dr. Chris has extensive experience providing care to the pediatric residents of Summit County, having established her practice here in 2000, following 20 years as a pediatrician on Saipan, in the Northern Mariana Islands, southeast of Japan. She has a unique perspective on high altitude health, having transitioned from sea level to the 8000′ and above elevations unique to Summit County. Since moving here, she has been advocating for more in-depth medical research regarding the needs specific to these high-altitude communities. We are here in her office today at the Ebert Family Clinic to discuss neonatal oxygen use in Summit County.

Dr. Chris, based on your experience, why do neonates need oxygen at a higher elevation? Is it because they need to acclimate?

Yes, that’s basically it, and smaller lung size at birth.

Yes, that’s what I read. Basically, the maternal physiology compensates for the higher altitude. When the infant is born, their lung size and physiology need to catch up to the altitude.

Based on your practice, when do you place neonates on oxygen?

Usually at 89% or below, but you see, that’s just it. Many parents ask why their children need to be on oxygen when neither themselves nor their siblings were on oxygen. One of the primary reasons that this has become more of an issue is the less invasive methods of measuring oxygen saturation in the blood. Before the 1990s, the only time to measure oxygen saturation in a newborn was if a concern for illness or pulmonary problems existed, which was completed by obtaining an arterial blood gas, a very invasive procedure. Do you know at what oxygen saturation level we begin to detect cyanosis in neonates?

Around75%, which means before the pulse oximeter used today, we had no idea if the infant’s oxygen saturation was in the 80s! Now that we have the pulse oximeter, we have access to so much more information. And this is why it is essential to determine the normal oxygen levels for these infants at higher elevations.

Does this include cyanosis or blue discoloration of the hands and feet, or is it just central as in the face and chest?

The blue discoloration of legs and arms do not count; this is very common and not concerning, only the discoloration of the trunk and face.

Yes, based on the articles that I have been reading while I have been here, there are not many studies that reflect normal oxygen saturation in neonates at a higher elevation. Most of the articles that I did find determined that newborn oxygen saturation is lower at elevations of around 6000’, with average values within the range of 89-96% SpO2 compared to greater than 97% at sea level. However, there could be a significant difference between 9000’-10000’ feet and the 6000’ in these studies.1-3

That is exactly right, and that is why I want to do a study here in Summit County to determine the average oxygen saturation at these altitudes.

On average, how many newborns do you place on oxygen in Summit County?

About 40% of newborns are placed on oxygen due to low oxygen levels at birth, and I would say that less than 5% will still need oxygen after their two-week visit; however, this rate may be higher in those that live at elevations of 10,000′ or greater. In general, studies have observed that the lowest oxygen levels tend to occur around the 4th day of life and then improve from this point onward. What is the main complication that we are worried about in infants that have low oxygen levels?

Pulmonary hypertension. At birth, when the fetal circulation is shunted back through the lungs, the pulmonary pressure decreases to allow this to happen. If the oxygen levels are too low, the vessels in the lungs may not dilate enough, and this could lead to elevated pulmonary pressures. I read an interesting study that found increased pulmonary pressures in Tibet children as measured by ECHO cardiogram until the age of 14. These pressures were noted to increase with increasing elevation but to decrease with increasing age. Generally, by the age of 14, the pulmonary pressures had normalized; the authors considered this to be a normal physiological response. However, it is worth noting that these children in the study came from generations of individuals that have always lived at these altitudes.4-5

That is correct. That is the difference between adaptation and acclimatization. Many of the children that live up here are acclimatized, meaning that their bodies have adapted on a physiological level, but their genetics remain the same. However, adaptation is observed in many families that have lived at high elevations for generations; in these instances, the changes have occurred at the genetic level.

That makes sense; so the data from some of those studies may not directly apply to the population here.

That is correct. Are we worried about brain damage in this setting of low blood oxygen levels?

No, I do not think so.

We are not! In fact, as an example of this: when I was in Saipan, there was a child that had a cyanotic, congenital heart defect that was unable to be repaired for social reasons. This child always appeared blue, and his oxygen saturation would have been very low. He did just fine in terms of development and progress in academics. There were no signs of developmental delay or any other neurological problems at all.

Are there any resources you recommend for parents whose newborn may need to be on oxygen?

Yes, I have a handout that I provide to all families whose infants are on oxygen. (View Dr. Chris’s handout here.)

Are there any red flags or signs that the newborns’ oxygen may not be high enough when they are sent home? Is there anything parents should look out for? I know that you mentioned the oxygen level needs to be as low as 75% before there are any signs of concerning central cyanosis.

No, there really are no clinical signs. A company called Owlet produces a sock for the newborn’s foot that monitors oxygen saturation. I am not sure how accurate this is, but if the parents really want to do something to monitor the oxygen level, this could be a way to do so. It is pretty expensive. On an aside, we are currently in communication with this company regarding future opportunities to conduct research using their product with regards to newborn oxygen saturation at higher elevations, so stay tuned for more developments on this topic.

Are there any risks to starting the infant on oxygen?

No, not at the level that these newborns are sent home on. In premature infants, there is a risk associated with oxygen therapy for eye and lung disease. However, these premature infants are placed on very high flow rates and positive pressures. The damage is actually caused by the pressures of the oxygen being too high. This is not the case for the newborns that we place on oxygen.

Are there any risks to infants or children growing up at high altitude?

Yes, there is some evidence of a very slight increased risk of pulmonary hypertension, but this is very rare.

Thank you so much for taking the time to discuss this, Dr. Chris!

References

  1. Ravert P, Detwiler TL, Dickinson JK. Mean oxygen saturation in well neonates at altitudes between 4498 and 8150 feet. Adv Neonatal Care. 2011 Dec;11(6):412-7. doi: 10.1097/ANC.0b013e3182389348. Erratum in: Adv Neonatal Care. 2012 Feb;12(1):27. PMID: 22123474.
  2. Morgan MC, Maina B, Waiyego M, Mutinda C, Aluvaala J, Maina M, English M. Oxygen saturation ranges for healthy newborns within 24 hours at 1800 m. Arch Dis Child Fetal Neonatal Ed. 2017 May;102(3):F266-F268. doi: 10.1136/archdischild-2016-311813. Epub 2017 Feb 2. PMID: 28154110; PMCID: PMC5474098.
  3. Bakr AF & Habib HS, Normal Values of Pulse Oximetry in Natewborns at High Altitude. Journal of Tropical Pediatrics 2005; 51(3) 170-173.
  4. Qi HY, Ma RY, Jiang LX, et al. Anatomical and hemodynamic evaluations of the heart and pulmonary arterial pressure in healthy children residing at high altitude in China. Int J Cardiol Heart Vasc. 2014;7:158-164. Published 2014 Nov 12. doi:10.1016/j.ijcha.2014.10.015
  5. Remien K, Majmundar SH. Physiology, Fetal Circulation. [Updated 2020 Aug 11]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2020 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK539710/
  6. Thilo EH, Park-Moore B, Berman ER, Carson BS. Oxygen Saturation by Pulse Oximetry in Healthy Infants at an Altitude of 1610 m (5280 ft): What Is Normal? Am J Dis Child. 1991;145(10):1137–1140. doi:10.1001/archpedi.1991.02160100069025

Austin Ethridge is a second-year physician assistant student at the Red Rocks Community College Physician Assistant Program. Originally from the Colorado front range, Austin attended the University of Northern Colorado where he obtained both a bachelors and masters degree in chemistry prior to attending PA school. In his free time, Austin enjoys spending time with his friends and family, reading, and cycling.

WMS Blog Entry No. 3: Pre-acclimatization, A Synopsis of Dr. Peter Hackett’s Lecture

What is pre-acclimatization? It is a process of adjusting to a new climate, usually higher elevation, reducing hypoxemia in high altitude settings in turn saving time, money, and most importantly, reducing altitude sickness. It can also allow for better sleep/comfort and physiological/cognitive performance at a high altitude. Acclimatization is a time-dependent process as over 5,000 genes are impacted by a large shift in elevation affecting ventilation, plasma volume, and hemoglobin mass, among other things. The whole process is not completely understood, but one key element is the hypoxic ventilatory response (HVR). HVR is activated by the aortic artery baroreceptors, as oxygen in the blood reduces it triggers an increase in respiration. This happens immediately as you ascend in altitude and maximizes at 7-14 days. Arterial oxygen increases by an increase in ventilation/saturation and also by dropping plasma volume, increasing hemoglobin concentration, and then later on, increasing overall Hgb production which in theory, overall decreases altitude sickness.

So how can you prepare yourself or pre-acclimatize?

Some of the better-known methods are spending time at higher altitudes prior to your destination, using a hyperbaric or normobaric chamber, blood doping, hypoxic exercise training, and a few pharmaceutical methods. All of these are options, but the key question is, which ones truly work?

Pre-acclimatization with actual altitude is the most useful. Generally speaking, you would pick your maximum sleeping altitude at your destination and slowly work your way towards that altitude. You pick an ascent profile which preferably would be spread over a week or more to be most useful. This pre-acclimatization should be completed no more than 1-2 weeks prior to your destination so that any pre-acclimatization gained doesn’t wane prior to your trip.

Simulated altitude is another option which includes hypoxic tents, hypoxic rooms/homes, hypoxic exercise chambers, and hypoxic masks. Out of these four, hypoxic tents or hypoxic rooms/homes, where exposure is over a long duration, are by far the most effective. Hypoxic masks and exercise chambers are not very effective as their short duration does not give the body enough time to make the proper adjustments and although might be beneficial in respiratory muscle training/performance, do little in the way of pre-acclimatizing your body. Studies show more benefit from hypobaric hypoxia training vs normobaric hypoxia training but keep in mind studies are very limited and warrant much further research. Overall, simulated altitude minimum requirements look to be somewhere in the range of 1 week of exposure, 7 hours per day, and a minimum effective altitude of 2200-2500 m and being no more than 1500-2000 m below your target sleeping altitude. Shorter term protocols can attenuate altitude sickness but not the incidence some studies suggest. As to why hypobaric methods are more effective than normobaric methods, no one really knows yet and more research is needed.

Changing your living destination to something at a much higher elevation and exposure over years or moderate altitude residence (MAR), is the most effective method according to some studies, but this is far from feasible for most. There are studies to show epigenetic changes for those who relocate to higher elevations for long periods and these appear to be much less than those who have genetically adapted to higher elevation over generations but still more effective than the previous mentioned short-term options.

Hikers often camp at the Angel of Shavano campground before ascending Mt. Shavano, one of Colorado’s famed fourteeners.

Oxygen saturation is maximal at 11 days of exposure to a specific elevation. Diamox (acetazolamide) increases ventilation and can help with acclimatization but there isn’t much data on how using this pharmaceutical compares to other methods mentioned. World-renowned high altitude expert and pioneerDr. Peter Hackett theorizes that it may fall just short of MAR, but again, more research is needed. Short-term altitude exposure shows benefits at 7 days but a longer exposure such as 15 days has been shown to be much more beneficial.

Blood doping with EPO can be somewhat effective over a 4+ week treatment and can potentially decrease AMS and potentially increase exercise performance but the data is limited and conflicting on this. Also, it appears that it is only effective up to 4,300 m but not beyond that as arterial oxygen content is not the determining factor for sleep and cognition performance at high altitudes but rather oxygen delivery which is affected by hematocrit and viscosity of blood.

Hypoxia inducible factor (HIF) is a regulatory factor in cells that respond to a reduction in oxygen, causing changes in about 5000 different genes to help the body adjust to meet oxygen requirements. It is suggested that we could pharmaceutically activate this factor prior to destination in order to acclimatize the patient allowing for less complications and better results at higher elevations. Currently there are some drugs in trials but nothing specifically FDA approved.

Overall, data and studies are limited but the most effective current pre-acclimatization method is long-term altitude training (real or simulated). If possible, plan your ascent trip to be slow and steady to obtain best results with the least amount of complication.

Joel Miller is currently preparing to graduate from Red Rocks Community College’s reputable Physician Assistant program this Fall. He has been a resident of Colorado for four years where he has immensely enjoyed the outdoors camping, fishing, hiking, hunting, and exploring Colorado’s wide variety of breweries.

WMS Blog entry No. 1: The Rule of 3’s and other pearls from the annual Wilderness Medical Society Conference 2020

Over 800 participants from 25 countries joined the virtual conference this year which included Dr. Chris’ poster presentation on growth at altitude. Over the next several months we will extract the most relevant information to publish in our blog, starting with:

The Rule of 3’s

You can survive 3 minutes without oxygen

                              3 hours without shelter in a harsh environment

                              3 days without water

                              3 weeks without food

Dr. Christine Ebert-Santos presents her research on growth in children at high altitude, “Colorado Kids are Smaller.”

We will be sharing some of the science, experience and wisdom from these meetings addressing how to survive. For example, Dr. Peter Hackett of the Hypoxia Institute reviewed studies on how to acclimatize before travel or competition in a low oxygen environment.

Susanne Spano, an emergency room doctor and long distance backpacker discusses gear, how to build an emergency shelter in the wild, and when it is OK to drink from that refreshing mountain stream.

Michael Caudell presenting on plant toxicity.

Michael Caudill, MD shares what NOT to eat when you are stranded in the wilderness in his lecture on toxic plants.

Presentations included studies of blood pressure in people traveling from sea level to high altitude, drones delivering water to stranded hikers, an astronaut describing life and work at 400,000 m, what is the best hydration for ultra athletes, how ticks can cause meat allergy, and, as always, the many uses for duct tape.

Duct tape for survival.

We will also update you on the treatment of frostbite as well as a discussion about “Climate change and human health.”

Sign up for our regular blog updates so you can be updated on wilderness and mountain medicine!

Mountain Kids are Smaller

How does living at high altitude affect the human body? It’s a complicated question that researchers have been trying to answer for years.

It takes two things to grow: adequate nutrition and the body’s ability to convert calories into energy.  Observations over 20 years at the Ebert Family Clinic suggest that the decreased oxygen levels at altitude may interfere with optimal utilization of calories or decrease appetite and intake in small children.

After opening her pediatric clinic in Frisco, CO in 2000, Dr. Christine Ebert-Santos noticed that children living at high altitude are smaller than average. Dr. Chris and Meredith Caines Pollaro, an occupational therapist with expertise in feeding and growth in children, organized a group for parents of underweight children but did not find any consistent abnormalities. After this, Dr. Chris decided that smaller growth might be a normal pattern for little ones at altitude. The children were otherwise healthy, with nutritional analysis showing adequate intake, and no signs of endocrine or gastrointestinal problems.

Graduate student Aaron Clark reviewing high altitude growth charts with PA student Laura Van Steyn and Dr. Christine Ebert-Santos.

Research on growth in children at altitude is sparse. So, in 2009, Dr. Chris recruited her daughter Anicia Santos to launch a detailed data analysis.  Anicia worked with one of her math professors at the University of Colorado to convert the data into a unique growth chart for altitude which demonstrated the downward shift. Twice the number of infants and toddlers had weights below the 3rd percentile of the World Health Organization growth charts than at lower altitudes. Heights were also decreased. After years of gathering data, Dr. Chris and Anicia are getting ready to share their findings with the help of Logan Spector, PhD and graduate student Aaron Clark.

Spector, chairman of the department of epidemiology at the University of Minnesota, was concerned about his two nieces who lived in Summit County who were not fitting into the “normal” growth pattern. This sparked his interest in Dr. Chris’ research. He was able to recruit Clark to take on the project.

In the first study of its kind in North America, the growth charts of 970 kids living in Colorado’s high country are analyzed. With over 9,000 pieces of data, one thing is clear. From birth to 18 months of age, children living at altitude weigh much less than the average child. Length is also considerably decreased, though the weight discrepancies are more drastic. These findings were studied extensively and found to be statistically significant. Using the generalized estimating equation (GEE), Clark was able to analyze the data in a non-linear way. This compensates for correlated data. Clark created density graphs for both male and female children to depict these findings (see figures). When the graph line is fairly close to 1 on the y-axis, or a straight line across the top, this means there is little difference from the standard growth chart (age 2-18). The farther away from 1 on the y-axis, the more significant difference there is compared to standard growth charts (age 0-2).

There is no denying that something is causing these high-altitude children to fall off of the growth charts. The next logical question would be, what are the effects of this smaller growth rate? Initial research shows that children at altitude are catching up on the growth curve by age two. There does not appear to be any long-lasting deficits from the initial smaller growth.

After combing through research articles, a new study from Ladakh, India also displayed a correlation between children living at high altitude and smaller size. Specifically in Colorado, another study shows lower birth weights at high altitude, however, it does not follow the growth patterns of the children over time.

From what this research shows,  a unique growth chart for children living at high altitude would be helpful. A new growth chart would account for the variations in size seen at altitude. This could save thousands of dollars in unnecessary testing looking for underlying disease or endocrine deficiencies as well as the anxiety for parents being told that their child has failure to thrive or is not being fed. Instead of being concerned when a child falls low on the growth chart, one might expect to see smaller children at altitude.

There is still much research to be done in this field. Hopefully, this study will serve as fuel for future studies.

Laura Van Steyn is a 3rd year Physician Assistant student studying at Midwestern University in Glendale, AZ. She graduated from the University of Colorado in Boulder with a degree in integrative physiology. After that, she worked as a CNA at Littleton Adventist Hospital prior to starting PA school. She hopes to work in women’s health or dermatology after graduating. During her six weeks at Ebert Family Clinic, she has joined Dr. Chris for numerous hikes and has truly enjoyed escaping the Arizona summer heat!

References

Yang, W.-C.; Fu, C.-M.; Su, B.-W.; Ouyang, C.-M.; Yang, K.-C. Child Growth Curves in High-Altitude Ladakh: Results from a Cohort Study. Int. J. Environ. Res. Public Health 2020, 17, 3652.

Bailey, B.; Donnelly, M.; Bol, K.; Moore, L.; Julian, C. High Altitude Continues to Reduce Birth Weights in Colorado. Matern Child Health J 2019, 23(11): 1573-1580

COVID-19 Update: A Look at How the World’s Highest Altitude Populations Have Been Affected

As the gateway to Machu Picchu, the city of Cusco, Peru attracts over 3 million tourists from all around the globe each year. With this many people passing through the city, you can imagine why local residents feared the worst when the COVID-19 outbreak began. However, out of a population of approximately 429,000 people, the city has only four COVID-19 related deaths – three tourists who traveled to the area and one native with previous risk factors.

Machu Picchu

Machu Picchu, a UNESCO World Heritage Site, brings 3 million tourists from around the world to the Cusco region of Peru every year.

One death out of 196 confirmed cases for the city makes for a remarkably low fatality rate of 0.5% for the native population. Peru as a whole has a fatality rate closer to 3% with over 6,000 deaths, making it one of Latin America’s most affected countries. Many believe the fatality rate to be even higher as testing has not become widely available in the country.

To understand why Cusco is such an outlier when compared to the rest of the country, there are several factors to take into consideration. One of those factors that researchers haven’t quite been able to figure out, but believe plays a role, is altitude. The Cusco region of Peru sits at 11,152 ft elevation compared to the capital city of Lima that sits at only 512 ft elevation.

Research comparing the high-altitude regions of Tibet, Bolivia, and Ecuador has revealed similar trends. A study completed April 22, 2020 and published in the June 2020 scientific journal “Respiratory Physiology & Neurobiology” indicates that populations living above 9,842 feet elevation reported significantly lower levels of COVID-19 cases than populations living at lower elevations. The research showed the infection rates in the Andes Mountains of Bolivia were one third the infection rates the rest of Bolivia, and the infection rates in the Andes Mountains of Ecuador were one fourth of the rest of Ecuador. In both Bolivia and Ecuador, the areas with the highest concentration of COVID-19 cases were located at an elevation close to sea level.

At an elevation of 11,942 ft, La Paz, Bolivia is the highest capital city in the world.

Why populations living at higher altitudes are experiencing lower infection rates is still not well understood, but there are a few theories at play. It is hypothesized that people living at altitude are able to live in a state of chronic hypoxia, or a state of chronically low oxygen in the blood. Hypoxia is one of the conditions caused by COVID-19, and if a person’s body is already used to low levels of oxygen, their symptoms may not be as severe. There are other environmental considerations at altitude that may shorten the life-span of the COVID-19 virus, including high levels of UV radiation that can kill the virus, low barometric pressure that does not support the weight of the aerosolized droplets that the virus lives in, and dry thin air that does not support the transmission of aerosolized droplets.

However, as intriguing as the effect of altitude on COVID-19 statistics is, it is important to note that there are several other proven factors that come into play when looking at these populations. First, most high-altitude towns and cities tend to be rural. When population density per square mile drops, the rate of transmission of infectious diseases also drops – rural settlements allow for natural social distancing. Second, populations living at higher altitudes have lower rates of obesity and generally have better overall health. Living at high altitude causes a reduction in the hormones that signal hunger, leading to consumption of fewer calories. Additionally, completely normal daily activities in a state of chronic hypoxia due to low levels of available oxygen in the air raises the body’s resting metabolic rate, leading to burning more calories. The healthier a person is prior to contracting an illness, the more likely their body is to be able to fight it off successfully.

Research regarding how altitude affects COVID-19 transmission, infection, and recovery rates is ongoing. It may be too soon to tell exactly why or how altitude comes in to play, but early findings are suggesting that now is a great time to be a resident of the great Rocky Mountains – but then again, when is it not?

References

https://www.washingtonpost.com/world/the_americas/coronavirus-andes-peru-ecuador-bolivia-tibet-high-altitude/2020/05/31/0b2fbf98-a10d-11ea-be06-af5514ee0385_story.html

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7207123/

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7175867/

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5094724/

https://en.wikipedia.org/wiki/Machu_Picchu#/media/File:80_-_Machu_Picchu_-_Juin_2009_-_edit.2.jpg

https://en.wikipedia.org/wiki/Machu_Picchu#/media/File:80_-_Machu_Picchu_-_Juin_2009_-_edit.2.jpg

Megan Schiers is a 3rd year Physician Assistant student studying at Midwestern University in Glendale, AZ. She graduated from Idaho State University in Pocatello, ID with a Bachelor of Science in Dental Hygiene and worked as a dental hygienist in Strasburg, CO for two years prior to starting PA school. She is passionate about increasing access to healthcare in rural areas and hopes to specialize in emergency medicine or cardiothoracic surgery following graduation this fall. During her six weeks in Frisco, CO, she has enjoyed hiking in the beautiful mountains, camping at Camp Hale Memorial, visiting Maroon Bells, and checking out Black Canyon of the Gunnison National Park.

COVID in Colorado Update: Reasons high altitude residents may be less susceptible

Last week we were privileged to have a Zoom discussion with two high altitude experts from the Instituto Pulmonar Y Patologia de la Altura (IPPA) founded in La Paz,  Bolivia in 1970. Dr Gustavo Zubieta-Calleja and Dr. Natalia Zubieta-DeUrioste answered our questions about their recently published article, Does the Pathogenesis of SAR-CoV-2 Virus Decrease at High Altitude?. They and the seven  coauthors presented data comparing COVID cases in high altitude areas of China, Bolivia and Ecuador showing a marked reduction in numbers compared to low altitude areas in the same countries, with dramatic, colorful topographic maps.

Drs. Zubieta-Calleja and Zubieta-DeUrioste and their colleagues theorized four reasons why altitudes above 2500 m could reduce the severity of the corona virus. (Note: Frisco, CO is at 2800 m, Vail 2500 m). As described in their previous paper published in March, the intense UV radiation at altitude as well as the dry environment likely reduce the viability of the virus in the air and on surfaces.

Dr. Zubieta-Calleja on a Zoom chat with Dr. Chris explaining a chart comparing UV exposure in La Paz, Bolivia (top line) and Copenhagen, Denmark (bottom line).
Dr. Chris with Dr. Gustavo Zubieta-Calleja and other altitude experts from the Hypoxia Conference in La Paz on the Camino Chacaltaya, which reaches an elevation of 17,785’/5421 m.

The low barometric pressure causes air particles to be spaced more widely, which would also decrease the viral particles inspired with each breath, reducing the severity and frequency of infections.

Furthermore, residents accustomed to chronic hypoxia may express reduced levels of angiotensin converting enzyme 2 (ACE2) in their lungs and other tissues. This enzyme has been found to be the entry path for the corona virus into cells where it replicates. Finally, the normal adaptation and acclimatization of populations with prolonged residence above 2500 meters may reduce the severity of the disease in individuals, and reduce mortality. This includes increased ventilation, improved arterial oxygen transport, and higher tissue oxygenation mediated by increased red blood cells produced under the influence of erythropoietin, which could be explored as a possible therapy.

Dr. Zubieta-Calleja with statistics reflecting the number of COVID-19 infections at different elevations in Bolivia. Note the most infections occur at a lower elevation.

As we stated in our interview quoted in the Summit Daily News March 17th, none of these factors can be relied upon to protect every individual. Therefore it is important to continue frequent hand washing, wearing masks, social distancing, and avoid touching your face.