Monthly Archives: February 2026

Acclimation, Altitude Science, Exposure, Health, High Altitude, Technology

From Mountains to Mars: Why High-Altitude Research Matters for Mars Missions

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Thin Air

You step out of your car at roughly 9,000 feet in Frisco, Colorado, and the first thing you notice isn’t the mountain views –it’s your breath. It comes faster, deeper, almost as if your body knows something you don’t: the air pressure here is lower and each breath delivers ~28% fewer oxygen molecules than at sea level1. This “thin air” triggers the same hypoxic (low-oxygen) stress that Mars settlers will face, where every habitat and spacesuit must carefully control both pressure and oxygen1,2,7,8. On Mars, the atmospheric pressure is less than 1% of that on Earth.

Acclimatization

On your first hike, your heart pounds harder than usual. That’s your body’s rapid response: breathing quickens, heart rate rises, and oxygen delivery ramps up to keep the entire body going1,2,4. Within 24-48 hours, your kidneys release erythropoietin (EPO), signaling the bone marrow to make more red blood cells1,3. This raises hemoglobin levels, enhancing oxygen transport. Over the following weeks, blood volume and hemoglobin continue to rise1,2,4. This is acclimatization –which varies between individuals, an important consideration when selecting crew for long-duration Mars missions.

Sleep and Oxygen

At night, breathing becomes fragile. Many people develop “periodic breathing” –brief pauses that fragment sleep. Summit County residents often experience oxygen dips into the high 80% –lower than the ~90% seen in Denver; and far below the typical 96-98% at sea level1. These dips have real implications: hypoxia combined with sleep disruption can affect mood, stress, and cognitive performance, as seen in Antarctic “winter overs,” where low oxygen and isolation caused up to 20% drop in certain cognitive task speeds and increased mood disturbances. Altitude sleep data are useful for researchers to determine extra nighttime buffers and habitat controls. Predicting and mitigating these person-specific patterns is key for astronaut safety and performance4,5.

From Frisco to the Final Frontier

Frisco, Colorado is not just known for its scenic views. This mountain town serves as a “living laboratory”, allowing researchers to track oxygen saturation, breathing, heart rate, sleep, and exercise tolerance in residents and visitors. These insights can help engineers determine how much oxygen a Mars habitat should provide, and how quickly conditions can safely change after landing1,2,7,8. NASA spacecraft air pressures currently range from 8.2 – 14.7 psi, with oxygen comprising 21-32% of that air; parameters informed in part by high-altitude research7,8. At the 7th Chronic Hypoxia Symposium in La Paz, Bolivia at 12,000 feet elevation (3,640 m) the use of insights from high altitude populations to enable the exploration of Space was discussed. The sponsor and organizers were Drs. Gustavo Zubieta-Calleja and his daughter Natalia Zubieta De Urioste who run the Institute of High Altitude Pulmonology and Pathology there. Presenters and attendees came from 16 countries covering topics ranging from molecular biology to genetics.
A presentation on “BioSpaceForming”  identifies chronic hypoxia as a “fundamental tool” that “gives humans and other species an advantage on earth and beyond.” Dr Zubieta explained that the space station is engineered to have the barometric pressure (760 mmHg) and oxygen content of sea level. When the astronauts change into their space suits to work outside the ship they experience a pressure drop of over 200 mm Hg in a laborious process of donning the suit. Seeing that millions of inhabitants are healthy at 486 mm HG in Bolivia, he advocates that maintaining lower pressures and lower oxygen levels in the space station would be economical and promote the health of the astronauts. Several altitude scientists see this as a future that “uncouples biology and physics.

(Photo of Dr Gustavo in front of space slide)

Modeling Mars Conditions

Researchers combine data from high-altitude locations, Antarctic stations, Mars-analog habitats like HI-SEAS in Hawaii to build predictive models. These models provide guidelines for when oxygen supplementation or workload adjustments are needed to optimize safety while completing tasks 4-6,9. They also help develop “operations playbooks” for simulating life on Mars10; set habitat air pressure and oxygen guidelines7,8; define spacesuit safety limits4,6,11; and better understand how the human body responds to spaceflight and space living2,5,9,12,13. For example, extravehicular activity (EVA) suits –spacesuits used for work outside the spacecraft –typically operate at ~4.3 psi with 100% oxygen. While this allows astronauts to breathe in low-pressure environments, prolonged use can lead to overheating, dehydration, and higher risk of injuries11.

The gravitational pull is 38% of that on Earth. Solar and the more dangerous Galactic Cosmic Radiation of Alpha particles from distant supernovae is hundreds of times greater than on Earth, due to the lack of a magnetic field or protective atmosphere. A breeze on Mars could barely move a blade of grass. Global dust storms occur every few years and last months, devastating the surface.

At the 9th  Chronic Hypoxia and First International Space Physiology Symposium in La Paz, Bolivia in 2025 Dr. Akbar Hussain presented his Craterhab design for accommodations in austere high altitude environments and eventually on Mars.

(PHOTO akbar in front of slide with craterhub) 

Astronauts could be acclimatized before embarking on the long journey to distant space in facilities located at 5,000 meters near mines in the Andes.

(Photo of Dr Gustavo in front of space slide)

Limitations

Most high-altitude studies are conducted over weeks to months, while Mars missions could last years and require hundreds of participants to have the skills to be self-sustaining. Due to planetary rotations, travel to Mars is only feasible once every 26 months. Messages from Mars take 7 to 45 minutes to arrive on Earth. Individual differences in acclimatization, long-term cognitive effects, and combined stressors like radiation or microgravity are not fully captured. Longer-duration studies at high-altitudes, combined with simulated Martian habitats and spacesuit trials, are needed to refine safety parameters.

Conclusion

High-altitude research gives scientists a window into human maladaptive and adaptive responses to low-oxygen, low-pressure conditions on Earth, and is directly relevant to anticipating health risks and necessary countermeasures for human habitation on Mars.

References

  1. Ebert-Santos C. High-Altitude Pulmonary Edema in Mountain Community Residents. High Alt Med Biol. 2017 Sep;18(3):278-284. doi: 10.1089/ham.2016.0100. Epub 2017 Aug 28. PMID: 28846035.
  2. Le Roy B, Martin-Krumm C, Pinol N, Dutheil F, Trousselard M. Human challenges to adaptation to extreme professional environments: A systematic review. Neurosci Biobehav Rev. 2023;146:105054. doi:10.1016/j.neubiorev.2023.105054.
  3. Roach RC, Hackett PH. Frontiers of hypoxia research: acute mountain sickness. J Exp Biol. 2001 Sep;204(Pt 18):3161-70. doi: 10.1242/jeb.204.18.3161. PMID: 11581330.
  4. Mairesse O, MacDonald-Nethercott E, Neu D, et al. Preparing for Mars: Human sleep and performance during a 13-month stay in Antarctica. Sleep. 2019;42(1). doi:10.1093/sleep/zsy206.
  5. Pagel JI, Choukèr A. Effects of isolation and confinement on humans—Implications for manned space explorations. J Appl Physiol (1985). 2016;120(12):1449-1457. doi:10.1152/japplphysiol.00928.2015.
  6. Dunn Rosenberg J, Jannasch A, Binsted K, Landry S. Biobehavioral and psychosocial stress changes during three 8–12 month spaceflight analog missions with Mars-like conditions of isolation and confinement. Front Physiol. 2022;13:898841. doi:10.3389/fphys.2022.898841.
  7. Waligora JM, Horrigan DJ, Nicogossian A. The physiology of spacecraft and space suit atmosphere selection. Acta Astronaut. 1991;23:171-177. doi:10.1016/0094-5765(91)90116-M.
  8. Morgenthaler GW, Fester DA, Cooley CG. An assessment of habitat pressure, oxygen fraction, and EVA suit design for space operations. Acta Astronaut. 1994;32(1):39-49. doi:10.1016/0094-5765(94)90146-5.
  9. Sarma MS, Shelhamer M. The human biology of spaceflight. Am J Hum Biol. 2024;36(3):e24048. doi:10.1002/ajhb.24048.
  10. Lim DSS, Abercromby AFJ, Kobs Nawotniak SE, et al. The BASALT research program: Designing and developing mission elements in support of human scientific exploration of Mars. Astrobiology. 2019;19(3):245-259. doi:10.1089/ast.2018.1869.
  11. Stirling L, Arezes P, Anderson A. Implications of space suit injury risk for developing computational performance models. Aerosp Med Hum Perform. 2019;90(6):553-565. doi:10.3357/AMHP.5221.2019.
  12. Cassaro A, Pacelli C, Aureli L, et al. Antarctica as a reservoir of planetary analogue environments. Extremophiles. 2021;25(5-6):437-458. doi:10.1007/s00792-021-01245-w.
  13. Fairén AG, Davila AF, Lim D, et al. Astrobiology through the ages of Mars: The study of terrestrial analogues to understand the habitability of Mars. Astrobiology. 2010;10(8):821-843. doi:10.1089/ast.2009.0440.
  14. Akbar Hussain M, Ayaz Hussain M, Mehdi Hussain M, Fatima R, Carretero R, eds. Craterhab Technology: Adapting Martian Habitat Systems to Combat Chronic Hypoxia in High-Altitude Mining in the Andes – A White Paper. Mareekh Dynamics. Published June 3, 2024. Accessed August 15, 2025. https://www.mareekh.com/post/craterhab-technology-adapting-martian-habitat-systems-to-combat-chronic-hypoxia-in-high-altitude-mi
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.