Monthly Archives: July 2023

Backcountry, Backpacking, Exposure, Health, High Altitude, Huts, Mountaineering, Summit Huts

Lightning Strikes in Colorado

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My love for hiking developed during my childhood explorations of the breathtaking landscapes of the Sierra Nevada. As I ventured into the rugged mountains and hiked along scenic trails, I couldn’t help but feel a deep connection with nature. However, my passion for hiking was not without its moments of caution. On several occasions, I witnessed the awe-inspiring yet intimidating power of lightning storms dancing across the vast mountain skies. These encounters instilled in me a profound curiosity about the risks associated with lightning strikes in high-altitude regions.

When I moved to Colorado for PA school, my awareness of the dangers posed by lightning strikes grew even stronger. The dramatic topography and frequent thunderstorms in Colorado amplify the risk for individuals exploring high-altitude areas. It was during my last clinical rotation at a burn unit that I had the opportunity to care for several patients who had been struck by lightning. Witnessing the effects firsthand fueled my determination to educate the public about the actionable steps they can take to stay safe during lightning storms.

Lightning strikes

​Lightning possesses an immense amount of energy, with a voltage of over 10 million volts (in comparison, most car batteries measure 12.6 V).1 Additionally, a lightning bolt reaches incredibly high temperatures, reportedly up to 30,000 Kelvin (53540.33 F).1 Lightning injuries occur in different ways, including as direct strikes, side splash, contact injuries, or ground current. 

Direct strikes are uncommon, accounting for only 5% of cases, and happen when a person is directly struck by lightning.2

Contact injuries occur when a person touches an object that is struck by lightning. 2

Side splash injuries occur when the current jumps or “splashes” from a nearby object and then follows the path of least resistance to reach the individual. These injuries make up about 1/3 of all lightning related injuries. 2

Ground current is the most prevalent cause of injury, accounting for half of all cases, and occurs when lightning strikes an object or the ground near a person and subsequently travels through the ground to reach the individual. 2

In Colorado, an average of 500,000 lightning flashes hit the ground each year. Based on data since 1980, lightning causes 2 fatalities and 12 injuries per year throughout the state.3According to data since 1980, lightning causes an average of 2 fatalities and 12 injuries annually throughout the state. 3 Colorado ranked third in the United States for the number of lightning fatalities between 2005 and 2014, as depicted in Figure 1.

Fig. 1. Lightning fatalities by state. 3

The high number of injuries attributed to lightning in Colorado can be influenced by several factors. One of these factors is the easy access to high elevation terrain, such as 14ers (mountains with a peak elevation of at least 14,000 feet). This accessibility allows inexperienced outdoor enthusiasts to venture into potentially dangerous situations due to their lack of knowledge and preparation.

For instance, individuals who are not familiar with summer weather patterns may embark on a hike above the tree line late in the day, underestimating the risk of a storm forming. This lack of understanding puts them in an exposed and perilous position should adverse weather conditions arise.

Even with thorough preparation and extensive knowledge of weather patterns, it is still possible to find oneself in a situation where you have to weather a storm. Given that a significant proportion of Colorado’s hiking trails are located above the tree line, where appropriate shelter is sparse, hikers are more susceptible to lightning strikes in these exposed areas. 

Pathophysiology of Lightning Strike Injuries

The overall ratio of lightning injuries to deaths is 10:1 and there is a 90% chance of sequelae in survivors.4 The primary mechanism of injury in lightning strikes is the passage of electrical current through the body. The high voltage and current can cause tissue damage through several mechanisms, including thermal injury, electrical burns, and mechanical disruption of tissues. The severity of the injury depends on factors such as the voltage and current of the lightning bolt, the duration of contact, and the pathway the current takes through the body.

Lightning strikes can cause various types of injuries, with cardiac and respiratory arrest being the most common fatal complications.5 The path of least resistance determines the flow of electricity through different organs in the body, with nerves being the most conductive, followed by blood, muscles, skin, fat, and bone. 5 When lightning strikes, the electrical surge can induce cardiac arrest and cessation of breathing by affecting the medullary respiratory center. As a result, most patients initially present with asystole and may progress to different types of arrhythmias, commonly ventricular fibrillation. 5

Interestingly, there have been case reports documenting successful resuscitation of lightning strike victims who were initially apneic and pulseless for as long as 15 to 30 minutes. 5This has led to the recommendation that in the immediate aftermath of a lightning strike, individuals who appear to be dead should be prioritized for treatment.

Superficial skin burns are experienced by around 90% of lightning strike victims, but deep burns are less common, occurring in less than 5% of cases. A characteristic skin manifestation of a lightning strike is the Lichtenberg figure, which is considered pathognomonic. Neurological symptoms can also occur, including keraunoparalysis, which is a transient paralysis affecting the lower limbs more than the upper limbs. This paralysis is often accompanied by sensory loss, paleness, vasoconstriction, and hypertension, and is thought to result from overstimulation of the autonomic nervous system, leading to vascular spasm. In most cases, this paralysis resolves within several hours, but in some instances, it may last up to 24 hours or cause permanent neurological damage. 5

Additionally, it is common for lightning strike victims to have a perforated tympanic membrane (eardrum) or develop cataracts immediately following the incident. These injuries to the ear and eyes are associated with the intense energy of the lightning discharge. 6

What can hikers do to stay safe?

Preparation

Monitor weather forecasts: Stay updated on weather conditions before engaging in outdoor activities, especially in areas prone to thunderstorms. Pay attention to thunderstorm warnings or watches issued by local authorities. Having a mobile or handheld NOAA Weather Radio All-Hazards (NWR) can also be helpful as it can transmit life-saving weather information at a moment’s notice. 

In Colorado most thunderstorms develop after 11 am, so it is best to plan your trip so that you are descending by late morning.7 Fig. 2 shows number of lightning fatalities by time of day in Colorado between 1980 and 2020. The vast majority take place after the 11 am threshold.

Fig. 2  Lightning fatalities in Colorado by time of day3

What to Do If Caught in a Storm

If you can hear thunder, you are close enough to be struck by lightning. Lightning can strike up to 25 miles away from the storm. 7 Once you hear thunder, if possible quickly move to a sturdy shelter (substantial building with electricity or plumbing or an enclosed, metal-topped vehicle with windows up). Avoid small shelters, such as picnic pavilions, tents, or sheds. Stay sheltered until at least 30 minutes after you hear the last clap of thunder.

Fig 3. Areas to avoid when sheltering from lightning.

If you are outdoors and cannot reach a suitable shelter, avoid open areas, hilltops, and high places that are more exposed to lightning strikes. Seek lower ground and stay away from tall objects, such as trees, poles, or metal structures. Bodies of water, including lakes, rivers, pools, and even wet ground, are conductive and increase the risk of a lightning strike. Move away from these areas during thunderstorms. Separate group members by at least 20 ft as lightning can jump up to 15 feet between objects.

​If a strike is eminent (static electricity causes hair or skin to stand on end, a smell of ozone is detected, a crackling sound is heard nearby), the current recommendation is to assume “lightning position”, pictured in Fig. 4.

Fig. 4. Lightning position8

To potentially reduce the risk of ground current injury from an imminent lightning strike, another strategy is to insulate oneself from the ground. This can be done by sitting on a pack or a rolled foam sleeping pad. However, it’s important to note that this and the lightning position should be considered a strategy of last resort and not relied upon as the primary means of prevention. Maintaining this position for an extended period can be challenging, and it’s crucial to prioritize seeking proper shelter and following established lightning safety guidelines to minimize the overall risk of injury. 5

Case Study

25 YO F presents to the Burn Unit as a transfer from Cheyenne Regional Medical Center s/p lighting strike. Patient (pt) was caught in a thunderstorm on a hike and sheltered under a tall tree. Suddenly, she felt like she was being lifted up into the air and then dropped. Pt had a brief (<5 sec) loss of consciousness (LOC). When she woke up, she was completely numb and couldn’t move any of her extremities. Witness (friend) states the lightning splashed from the tree to the pt. Pt denies hitting her head with the fall. She denies taking blood thinners. She has no past medical history (PMHx) or past surgical history (PSHx).

Physical exam 

Neuro: AOX4, No CN deficit on exam, LE paralysis resolved, LE paresthesia improving but still present

HEENT: L ruptured tympanic membrane, hearing loss on L side

CV: RRR

MSK: Soft compartments diffusely

Skin: Lichtenberg figures on bilateral LE 

Fig. 6. Lichtenberg figure on LLE

V/S: BP: 128/92, HR: 96, RR:18, SPO2: 98%, Temp 98.1F. 

CBC, CMP, troponin were all WNL. Serum hCG negative. CK mildly elevated (222) 

EKG showed NSR.

CXR, CT brain, and c-spine neg for acute injury

She was admitted to the UC Health burn center for observation with tele. Her lab work and vitals remained stable throughout her hospitalization. She was evaluated by the trauma team with a negative trauma work up. The day of discharge, she was tolerating a regular diet, ambulating and sating well on room air. She was deemed appropriate for discharge home without patient audiology and ophthalmology follow up. 

References

1. US Department of Commerce N. Understanding lightning science. National Weather Service. April 16, 2018. Accessed July 8, 2023. https://www.weather.gov/safety/lightning-science-overview. 

2. Cooper MA, Holle RL. Mechanisms of lightning injury should affect lightning safety messages. 21st International Lightning Detection Conference. April 19-20, 2010; Orlando, FL. 

3. US Department of Commerce N. Colorado Lightning statistics as compared to other states. National Weather Service. March 4, 2020. Accessed July 7, 2023.https://www.weather.gov/pub/Colorado_ltg_ranking. 

4. US Department of Commerce N. How dangerous is lightning? National Weather Service. March 12, 2019. Accessed July 8, 2023. https://www.weather.gov/safety/lightning-odds. 

5. Chris Davis, MD; Anna Engeln, MD; Eric L. Johnson, MD; Scott E. McIntosh, MD, MPH; Ken Zafren, MD; Arthur A. Islas, MD, MPH; Christopher McStay, MD; William R. Smith, MD; Tracy Cushing, MD, MPH. Wilderness Medical Society Practice Guidelines for the Prevention and Treatment of Lightning Injuries: 2014 Update. WILDERNESS & ENVIRONMENTAL MEDICINE. 2014; 25, S86–S95 

6. Flaherty G, Daly J. When lightning strikes: reducing the risk of injury to high-altitude trekkers during thunderstorms. Academic.oup.com. Accessed July 8, 2023. https://academic.oup.com/jtm/article/23/1/tav007/2635599. 

7. NWS Colorado Offices – Boulder G. Colorado Lightning Awareness Week june 19-25, 2022. ArcGIS StoryMaps. June 25, 2022. Accessed July 8, 2023. https://storymaps.arcgis.com/stories/11d021f1b800429a869ead2dc32c0f96. 

8. McKay B and K. How to survive A lightning strike: An illustrated guide. The Art of Manliness. April 25, 2022. Accessed July 8, 2023. https://www.artofmanliness.com/skills/outdoor-survival/how-to-survive-a-lightning-strike-an-illustrated-guide/. 

A woman with long, light brown hair over her shoulders wearing a blue, sleeveless shirt with red details smiles with blue eyes.

Sophia Ruef is a Physician Assistant student at Red Rocks Community College in Arvada, CO. She grew up on the central coast of California and earned her Bachelor of Science degree inBiology with a concentration in anatomy and physiology from Cal Poly San Luis Obispo. She worked as an EMT and a tech in the Bay Area after her undergraduate education. In her free time, she enjoys hiking, backpacking, canyoneering, and spending time with family and friends.

Acclimation, Altitude Science, Doc Talk, Genetics, Health, High Altitude

RED FLAGS AT ALTITUDE: When Your Doctor Tells You Your Labs AreNormal But the Results in the Patient Portal Are Flagged

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It comes as no surprise that living at altitude can take some adjustment. Travelers visiting just for a quick ski trip recognize  immediately, sometimes even at Denver International Airport when first arriving at Colorado’s Mile High City at 5280 feet, that the air is “thinner” than where they might have journeyed from. That thinner air we all feel is due to our altitude living at 9,075 feet (2) here in Frisco, CO. Our bodies can feel the atmospheric changes even if we do not recognize them ourselves. As a point of reference, on the rather extreme side, the “death zone” that comes to mind when thinking of the behemoth Mount Everest, is any elevation of 26,247 feet and above (3), a  zone we might not be as familiar with is the deterioration zone which begins at a mere 15,000 feet (3). In this zone, the symptoms are variable, but  common manifestations are lethargy, weight loss, poor appetite, and irritability (4). Altitude experts identify 8,000 feet as the elevation where  symptoms such as headaches and pulmonary edema are more likely to manifest. The good and bad effects of altitude are proportional to the elevation and variable between individuals. For all of you ‘fourteener’ fanatics out there, including myself, this comes as a reminder that we are closer than we think to detrimental elevation in our atmosphere. With this  frame of reference fresh in our minds, let us take a closer look at how living in at the elevation of Frisco, Colorado at 9000 feet or the neighboring towns can affect our health. 

Mountain residents who have blood tests done commonly see “red flags” next to some lab values. In particular, the complete blood count, commonly referred to as CBC. To most of us, those red flags are an alarming indicator that something must be terribly awry but au contraire,  there is an explanation why we need not worry. For those of us living at altitude, there is a reduced atmospheric pressure, so although the fraction of oxygen in the air is still 21%, the molecules are further apart. Fewer oxygen molecules enter our lungs and bloodstream  delivering less oxygen to our tissues(5). Remember now, we are not living on top of Mount Everest, so we are not in any danger, because our bodies are doing behind-the-scenes work for us! Our bodies are adapting by increasing the amount of red blood cells, which carry oxygen in our blood, throughout our bodies so that every organ is being supplied with the good stuff! This is exactly why athletes come here to train, to get their bodies to produce more red blood cells so they can perform at their absolute best. After three months of life in the mountains, nearly everyone has elevated red blood cells, hemoglobin, hematocrit, and red cell indices such as the MCV, (mean corpuscular volume), MCHC (mean corpuscular hemoglobin content) and MCH (mean corpuscular hemoglobin). A “normal” hemoglobin in a man who lived for years in the mountains was a signal to his doctor that the patient was anemic and in fact turned out to have colon cancer.

A more immediate response to the low oxygen environment at altitude is an increase in respiratory rate. In an interview with physician experts on altitude Dr. Elizabeth Winfield and Dr. Erik Swenson on May 30, 2023, both think this is the reason there is often a red flag for the carbon dioxide (CO2) as low, usually 17 to 19 with 20 being normal.  Because this affects the acid base balance, the serum chloride ( Cl) may be slightly elevated, 107 to 108 instead of 106. Dr. Winfield also explains to her patients that fasting for labs may cause mild dehydration leading to a slightly higher BUN, blood urea nitrogen, a marker of kidney function.  Another physiological response to altitude is a lower plasma volume, which may cause slight elevation in the serum protein and albumin.

So when you doctor calls you and tells you your labs are normal, ask them to drill down and explain the red flags.  If you find out something new, please put a comment on our blog and share with the world! Few health care providers really understand all the changes in the human body living in hypobaric hypoxic (low pressure, low oxygen) environments.

References 

1. Image. https://ichef.bbci.co.uk/news/624/cpsprodpb/960F/production/_83851483_c0249925-red_blood_cells,_illustration-spl.jpg. 

2. Town of Frisco Colorado. (2023). Maps. https://www.friscogov.com/your-government/maps/. 

3. Lankford, H. V. (2021). The death zone: Lessons from history. Wilderness & Environmental Medicine, 32(1), pp. 114-120. https://doi.org/10.1016/j.wem.2020.09.002. 

4. West, J. C. (2013). Case law update. Legal liability in emergency medicine and risk management considerations. Journal of healthcare risk management: the journal of the American Society for Healthcare Risk Management, 33(1), pp. 53-60. 

5. Cabrales, P., Govender, K. and Williams, A.T. (2020), What determines blood viscosity at the highest city in the world?. J Physiol, 598: 3817-3818. https://doi.org/10.1113/JP280206

6. Image. https://cdn.allsummitcounty.com/images/content/5717_13913_Frisco_Colorado_Main_Street_lg.jpg

Accessibility, Acclimation, Altitude Science, Asthma, Athletic Training, Backpacking, Health, High Altitude, High Altitude Training & Fitness, Sleep at Altitude

Living With High Altitude Pulmonary Hypertension: An Interview with Karen Terrell

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by Jennifer Wolfe, NP-S

During my last week of a clinical rotation at Ebert Family Clinic in Frisco, Colorado, at 9000 feet, I was thrilled to have the opportunity to interview high altitude resident Karen Terrell with physician Dr. Chris Ebert-Santos.  During this time, we were able to discuss high altitude pulmonary hypertension, also known as NAPH. This is a condition that Karen has been living with since 2015.  NAPH is condition that can affect people that live above 8,200 feet, more than 140 million people live at this altitude worldwide, including the population of Summit County, where the town of Frisco, Colorado is. Pulmonary hypertension is a group of disorders that will typically be diagnosed during a heart catheterization measuring the mean arterial pressure of the right side of the heart.  These disorders are broken down into five groups. High altitude pulmonary hypertension is in group three. The primary symptoms that people first notice is extreme fatigue, difficulty getting air upon exertion, and difficulty engaging in their normal exercise routines.

How long have you lived in Summit County [Colorado], and where did you move from originally?

Karen: I grew up in Nebraska, I moved to New York City as soon as I was old enough to leave home.  I went to Boulder for school, and then moved to Denver for work.  I went to an Outward-Bound Experience, and I fell in love with this area.  I have lived in Summit County over 37 years. My kids were born and raised here; they are now in their 30s.

What are some of the things that you love to do in area?

Karen: I downhill ski, I uphill ski, and I cross country ski.  Mountain biking is my passion. I downhill bike, that is where you take the gondola to the top of the mountain and then ride your bike down.

When did you start to have symptoms?

Karen: 2015

What were the symptoms that you noticed first?

Karen: Extreme fatigue and erratic pulse, with or without exertion.  By the end of a run, I would be so exhausted that I was practically crawling home.

Do have to go on oxygen at any point?

Karen: In 2018 I started using oxygen at night. I still use oxygen at night.  In 2020 I started riding and skiing with portable oxygen. When my oxygen columns fail, so do I. It was also during this time I began to work on nasal breathing night and day.  I have been doing research on the importance of nasal breathing and retraining the body on how to take in oxygen.  Practicing nasal breathing is especially important when you are using a nasal cannula to get oxygen when you are being active.

An image of the OxyGo FIT portable oxygen concentrator with specifications.
https://oxygo.life/oxygo-fit

Dr. Chris Ebert-Santos:  The standard is “if you’re 50 and you’ve lived here 10 years and you want to live here for another 10 years you should be sleeping on oxygen.”

Between 2015 and 2018 did you have any other symptoms or worsening concerns?

Karen: In 2017 I applied for life insurance.  I was denied as I had what I now know is chronic proteinuria. The nephrologist was perplexed as to why someone who is as active as I am and takes no medication is having this condition.  The insurance company essentially told me that they would not touch me with a 10-foot pole.  This was the “canary in the mine” that made me think something was not right. In 2018, I had a cardiac ablation. The cardiac ablation corrected the erratic heart rate and relieved my extreme fatigue. However, it did nothing for my oxygen saturation.

You mentioned in 2020 that you started to ski and ride your bike with portable oxygen.  Did something happen in 2020, besides COVID?

Karen: You know, with everything that I have going on health wise I have been so cautious that I have not ever had COVID. In 2020, I was at an office visit with my PA. I mentioned that biking and skiing at higher elevation with exertion, that I felt flattened and near-dead.  My pulse oximeter showed oxygen saturation of low 70’s. My PA freaked out and thought I had Pulmonary Hypertension (as opposed to HAPH) and sent me to a Denver Pulmonary specialist.

What did the pulmonary specialist tell you?

Karen: When I went to the pulmonary specialist, they said my oxygen numbers were fine at Denver’s elevation. The Pulmonologist advised moving to lower elevation but said there is no knowing how low until I experiment.  I have lived in Summit County and raised my children here; my children still live here.  Moving was not an option. I started riding and skiing with portable oxygen. When 02 columns fail, so do I. I do have periodic episodes of extreme joint pain resulting from excessive stress/time at desk (10-hr days).  However, I try to eliminate the pain by remaining active using oxygen when I need it. If I don’t use oxygen to sleep, I feel half dead the next day and it is difficult to wake up the next day.  I worry about the long-term effects of the hypoxia, however I continue to monitor.  I am hoping to see more research done in the area of high-altitude pulmonary hypertension. 

Jennifer Wolfe is in her final semester of Nurse Practitioner school at Georgetown University. She was born and raised in Missouri and attended The University of Missouri where she graduated with a bachelor’s degree in psychology. After attending Mizzou she married her husband who was active duty in the US Navy. They traveled to many bases and had two boys before calling Denver their home in 2011.  Jennifer received her BSN from Denver College of Nursing. Jennifer has spent 7 years as a nurse in the emergency department of several level II trauma centers before starting at Georgetown as a part of the Family Nurse Practitioner program.  Jennifer enjoys spending her free time with her family and their three dogs.  

Acclimation, Altitude Science, Athletic Training, Child Growth & Development, Health, High Altitude, High Altitude Training & Fitness, Neonatal

Maternal Exercise and Its Effect on the Development of High-Altitude Pulmonary Hypertension in Children

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by Julia Wu, PA-S

Every newborn I have managed while rotating at Ebert Family Clinic in Frisco, Colorado at 9000′ has needed oxygen supplementation. It is known that at high altitudes, there is a lower oxygen concentration in the air, which poses challenges to our bodies. What exactly happens, and what are the consequences of chronic high-altitude exposure? There are approximately 140 million people that live at high altitudes, defined as at least 2500 meters above sea level, who are affected by chronic hypoxic conditions.1 In this article, I will focus on how hypoxia — low levels of oxygen in the blood — affects pregnant women, alters fetal to newborn transition and development, and whether cardiorespiratory exercise by mothers during pregnancy can prevent diseases such as high-altitude pulmonary hypertension (HAPH) development in offspring.  

Pulmonary hypertension (PH) is abnormally high blood pressure in the pulmonary arteries. PH is classified into 5 groups based on the cause. High-altitude pulmonary hypertension (HAPH) is Group III PH and defined as mean pulmonary arterial pressure (PAP) ≥25 mm Hg. Chronic high-altitude hypoxia can lead to the development of HAPH, which has adverse effects on the heart from right ventricular wall thickening to reduced cardiac output, and eventual right heart failure and death. HAPH can occur in utero, so it’s imperative to understand how hypoxia affects mothers and their fetuses during and after birth.2

During pregnancy, the fetus doesn’t breathe air and the lungs are not used. The fetus receives all its oxygen and nutrition needs from the mother’s blood, which flows through the blood vessels in the umbilical cord to the placenta and then to the baby.3 Circulating blood bypasses the lungs by flowing in different pathways through openings called shunts that close at birth to allow for adult circulation. In utero, the baby’s lungs fill with a special fluid that helps the lungs grow.4 The fluid in the lungs, in combination with naturally thicker pulmonary vascular and pulmonary vessel vasoconstriction from low PO2, causes higher vascular resistance in pulmonary circulation that allows for the diversion of blood away from the lungs through the shunts.2 At low altitudes, in the first few days after birth, the high PAP in the lungs drops. The sharp drop in PAP is due to “expansion of the lungs, pulmonary vasodilation from higher PO2, a gradual receding of fluid, a thinning of pulmonary vascular smooth muscle, and… closing of the [shunts]”. This process is known as cardiopulmonary transition. However, at altitude, perinatal hypoxia negatively affects cardiopulmonary transition. The elevated pressures in the pulmonary arteries and vascular resistance persist into early childhood delaying cardiopulmonary transition, which can have developmental consequences such as HAPH and right heart failure, as discussed.

It was discovered that cardiopulmonary transition delay is linked to a high-altitude hypoxia-induced proinflammatory state within the pulmonary vasculature that leads to pulmonary artery remodeling and HAPH. Hypoxia activates or upregulates transcription factor, nuclear factor kappa-light-chain-enhancer of activated B cells (NK-kB), that signals for inflammatory mediators such as hypoxia-inducible factors (HIF). HIF-1a inhibits mammalian target of rapamycin (mTOR). mTOR signaling has an important role in cell metabolism, cell proliferation, and survival, thus inhibiting mTOR prevents “non-proliferative branching and elongation of conducting airways and fluid removal from the lungs,” which contributes to increases in pulmonary vascular resistance and lung development during the cardiopulmonary transition and the onset of newborn gas exchange. 2,5 HIF also contributes to the uncontrolled proliferation and resistance to apoptosis of pulmonary artery smooth muscle cells (PASMC) which is also a crucial contributing factor to pulmonary vessel wall thickening, pulmonary vascular remodeling, and vascular resistance. 5 Metabolic studies showed that chronic hypoxia not only increased the expression of these proinflammatory molecules and mediators but also reduced anti-inflammatory products like omega-3 fatty acids.2

Studies have shown that cardiorespiratory exercise reduces proinflammatory markers and increases anti-inflammatory stimulus in healthy and HAPH populations.2 However, exercise training is not sufficient to reverse PAH, so we need to prevent HAPH from developing in utero with maternal exercise.  The American College of Obstetrics and Gynecologists (ACOG) recommends resistance training twice a week and moderate-intensity cardiorespiratory training daily for a total of 150 minutes a week. Studies showed that pregnant women who followed this recommendation had a 25% reduced risk of developing conditions like gestational diabetes and hypertension that contribute to compromised uterine blood flow and fetal hypoxic conditions. At low altitudes, exercise by pregnant mothers leads to benefits such as decreased fat mass, leptin, oxidative stress, pulmonary valve defects, aortic valve defects and inflammation, and increased neurogenesis in the fetus. Some animal studies at high altitudes showed that offspring of physically active pregnant rodents also received similar benefits from maternal exercise. The offspring were protected against proinflammatory stressors evidenced by low levels of inflammatory mediators, which protected them against the inflammatory processes that drive pulmonary artery remodeling and pressures that lead to HAPH. Further animal studies should be conducted to further explore the possibilities that maternal exercise can counteract the inflammatory changes and prevent HAPH development in fetus and newborns.

Resources

  1. Mirrakhimov AE, Strohl KP. High-altitude Pulmonary Hypertension: an Update on Disease Pathogenesis and Management. The Open Cardiovascular Medicine Journal. 2016; 10: 19-27. doi: 10.2174/1874192401610010019
  2. Leslie E, Gibson AL, Gonzalez Bosc LV, Mermier C, Wilson SM, Deyhle MR. Can Maternal Exercise Prevent High-Altitude Pulmonary Hypertension in Children?. High Altitude Medicine & Biology. 2023; 24: 1-6. https://doi.org/10.1089/ham.2022.0098
  3. 2023. Blood Circulation in the Fetus and Newborn. Stanford Medicine Children’s Health. https://www.stanfordchildrens.org/en/topic/default?id=blood-circulation-in-the-fetus-and-newborn-90-P02362
  4. 2023. Transient tachypnea- newborn. Icahn School of Medicine at Mount Sinai. https://www.mountsinai.org/health-library/diseases-conditions/transient-tachypnea-newborn#:~:text=As%20the%20baby%20grows%20in,start%20removing%20or%20reabsorbing%20it.
  5. He S, Zhu T, Fang Z. The Role and Regulation of Pulmonary Artery Smooth Muscle Cell in Pulmonary Hypertension. International Journal of Hypertension. 2020; 2020: 1478291. doi: 10.1155/2020/1478291