Tag Archives: physiology

Life at the Limits: Register now for our extreme environmental physiology conference

By Mike Tipton, @ProfMikeTiptonExtreme Environments Laboratory, Department of Sport and Exercise Science, Portsmouth University

“Ecology”, from the Greek “oikos” meaning home or place to live, is the branch of biology that deals with the relationships of organisms and their physical surroundings. It encompasses the impact of animals on their environment, and the environment on animals. Both sides of the ecology coin are becoming increasingly important and linked.

On one side we are careering, largely unfettered, towards the man-made abyss of the end game of global warming; we are threatening our direct descendants, but at a rate and distance that doesn’t provoke us to action.

On the other side, only 15% of the surface of our planet is not water, desert, ice or mountain. For a tropical, low altitude, air-breathing human, this means most of planet Earth represents an extreme environment, defined as a place where it is difficult to survive. The link between the two is, of course, that global warming will make our planet even more extreme with flooding, erosion, heat waves, cold snaps and desertification.

group of climbers on rope on glacier

Perhaps, therefore, there is no better time for The Physiological Society to plan a specialist conference on Extreme Environmental Physiology (EEP) on 2-4 September.

From origins where EEP research was largely undertaken for occupational groups such as miners and the military, as well as those attempting expeditions to remote parts of the globe, EEP has now become much more “mainstream.” The greatest number of submissions and publications in the journals of the Physiological Society come from the areas of “environmental” and “exercise” physiology; both of which have extreme environmental components.

EEP research continues to examine the responses of humans to environmental stressors such as heat, cold and altitude; these remain important areas in themselves with, for example, at least 1000 people dying from drowning every day around the planet. But EEP research is now also providing insights into a wide range of other conditions such as: responses to hypoxia on intensive care (“survivor phenotypes”); ageing; peripheral vascular disease; osteoporosis; and debilitation caused in critical care patients by bed rest.

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In addition, as we take greater and greater control of our environment through technology, it is becoming increasingly apparent that we need to challenge our homeostatic mechanisms in order to remain functional. At one time we did this naturally by exercise and exposure to the natural world, now we have to employ thermal therapies for a wide range of physiological and mental health pathologies, from microvascular function through autonomic function to depression.

The specialist conference at Portsmouth in September will reflect all of the above, with sessions on cold, heat, hypo- and hyperbaric physiology, micro-gravity and cross-adaptation. To remind us what an eclectic discipline physiology is, each session will include short keynotes on physiology, pathophysiology and comparative physiology, as well as plenty of time for free communications. Finally, it seems appropriate that we should “flip the coin” and spend some time on what the environment might have in store for us if we continue to damage it.

Our exciting keynote speakers include:

References

  1. Martin & McKenna (2017). High Altitude Research and its Relevance to Critical Illness. ICU Management & Practice 17(2): 103-105.
  2. Tipton MJ (2015). GL Brown Lecture: “Extreme Threats” Environmental extremes: origins, consequences and amelioration. Experimental Physiology. doi: 10.1113/EP085362.
  3. Tipton, M. J. (2018) Humans: a homeothermic animal that needs perturbation? Experimental Physiology. https://doi.org/10.1113/EP087450.

Early Career Conference: Join us in December!

Want to run a two-day early career physiology conference? This valuable experience will give you leadership experience and boost your CV! Any Affiliate and/or Undergraduate Members of The Society may apply. Read testimonials from our first Future Physiology conference in 2017 below. 

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Jose L. Areta, Norwegian School of Sport Sciences, Oslo, Norway:

Attending the Future Physiology meeting in Leeds in December 2017, coming all the way from Oslo, Norway, was a privilege I had thanks to a Physiological Society travel grant. I am a post-doctoral researcher in the early stages of what, I think, might turn into a long academic career. I signed up for this conference specifically to get a better overview and insights on what a researcher at my stage could do to make the right choices for his future career. The conference did not fail to provide valuable food for thought.

The attendees included a wide range of representatives of the academic career continuum, from undergraduates to professors. A majority of these were, seemingly, early career researchers (ECRs) and they belonged to a reasonably wide range of areas within the field of physiology. This showed that the purpose of the conference was to go beyond delving into their specific areas of expertise. A dominant topic of interest seemed to be commonalities irrespective of the specific area of expertise, meaning the ins and outs of working in and growing through academia.

Several of the sessions provided examples of more established researchers showcasing how they built their own academic careers in the context of research in physiology. The take-home message for me was that there is no one way to become an established researcher in any given area. The impression that I got is that love for the work you do followed by dedication and a solid network play a key role, immediately followed by serendipity. This seemed to provide some support to the saying ‘the harder you work, the luckier you get’, that I sometimes remind myself of.

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On that note, it was also nice to feel supported by other researchers going through similar difficulties in a research system that seems to very often put high-pressure on individuals and can lead to sub-optimal life quality and, in many cases, burnout. Uncertainty seems to be a common denominator for many researchers in different stages of their careers (more so ECRs). Making this explicit is important to find a solution for it. I think this conference was a good first step to bridge the gap between ECRs who have a lot of questions on how to progress through the ranks, while making meaningful contributions to science and more experienced researchers talking about their specific experiences or professionals providing advice.

Personally, one of my favourite events was a small grant-writing workshop I had the chance to attend that also turned into a bit of a career advice workshop. Transitioning towards being an independent researcher is very significant milestone for anyone in research, I think. Gathering some tools to do so in the context finding one’s place in the field was a nice addition to the experience of the conference.

In conclusion, I think this conference was a good first step to put the uncertainties that ECRs face throughout their development as researchers in the spotlight, and provide them (us!) with tools and networks for better tackling these.

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Dan Brayson, King’s College London, London, UK:

As a member of the Affiliate Working Group of The Society, I was privileged to have the opportunity to help with the planning and execution of the Future Physiology meeting, an early career researcher (ECR) focussed meeting held at the University of Leeds last month. The meeting was ‘by ECRs for ECRs’. This meant that the Affiliate Working Group was placed at forefront of the brainstorming process to come up with a plan for a meeting which facilitated an engaging experience for early career scientists.

What we hoped for was an opportunity for ECR’s to shed their inferiority complex baggage (we all have it), and to feel invigorated by the conference experience rather than being overwhelmed. To this end 20 ECRs were selected for oral presentations whilst five talks were given by senior scientists (for balance, of course). Of these, three were young PIs and shining examples that we don’t have to wait around for professors to retire in order to make significant progress in our careers. We hoped that this would add a motivational slant for attendees. If they can do it, why can’t we?

On a personal note it was a red letter day. I was charged with sharing the chairing and presentation-marking duties with my fellow Affiliate Working Group members, a first for me, and with this, I got to experience the joy of facilitating meeting proceedings rather than merely taking part. At least this was my perception of it, and I would definitely do it again.

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Reflecting now on the meeting I feel that it was a good first crack at a meeting for ECRs. However, I also feel that there is further scope to create the most engaging and immersive experience for young scientists. One idea would be to have facilitated debate workshops on general topics (neuroscience, cardiovascular physiology, gastrointestinal physiology etc.). This would engage people in a relaxed environment to talk more generally about the big issues/questions facing their chosen fields.

Friends in high places: Researchers go global for answers at high altitude (Part 1)

By Alexandra Williams, @AlexM_Williams

Global Research Expedition on Altitude Related Chronic Health (or Global REACH) is an international collaboration of academics and physicians from 14 institutions across Canada, the UK, the US, Peru and Nepal. While the “Global REACH” title is relatively new, its leaders have conducted a multitude of expeditions over the last decade to Nepal’s Himalaya, California’s White Mountains and now Peru’s Andes. With a collective interest in heart, lung and vascular health and altitude medicine, Global REACH’s collaborations ultimately aim to understand how the human body adapts, or maladapts, chronically to the low oxygen environments of earth’s highest altitudes.

I am writing this from 4,300 m, at the Laboratorio de Cerro de Pasco and Institutio de Investigaciones de la Altura in Peru. Our team of over 40 researchers, trainees, principal investigators and physicians are currently conducting approximately 20 studies examining heart, lung and brain physiology in lowlanders (us) and Andean highlanders with and without chronic mountain sickness.

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Example of a centrifuged blood sample from an Andean participant with chronic mountain sickness. A normal, healthy lowlander’s hematocrit (i.e. fraction of red cells in the blood) is ~40%; several Andean participants including this one had hematocrit values of 75-80%.

This series of blogs, however, does not intend to outline our experiments or specific scientific findings (which was described in a recent issue of Physiology News). Instead, you will get a raw, behind-the-scenes look at what transpires on these expeditions: the challenges we face, the experiences we gain, and most importantly the team values that drive the success of these international collaborations.

30 June 2018: Day 1 at altitude

Yesterday, the last of three groups of the Global REACH team drove from sea level in Lima up to 4,300 m in Cerro de Pasco, Peru. Amongst the team, some individuals are feeling “okay” (say, a rating of 7/10), while others have been in bed with splitting headaches for more than 24 hours. We would later discover that one, in fact, had a bout of pneumonia. Nevertheless, one thing remains constant across the team – the excitement. It is palpable. Seven lab bays are set up, participants are being scheduled in, the equipment is (mostly) accounted for and working. Data collection has already begun today, and our first Andean participants are coming in tomorrow morning. This is what we came for, and we’re ready for the fun to begin.

For those who haven’t experienced the thin air of Earth’s highest mountain ranges, a 7-hour jump from sea level to over 4,300 m altitude is significant, one which often leaves individuals feeling much worse than “not great.” Yet, with advanced knowledge of the side effects of altitude and hypoxic exposure, Global REACH members have joined forces to answer a plethora of physiological questions. For many, this will mark more than four expeditions to high altitude, a select few even in the double digits. In the first few days, most – including our team leaders – will have headaches, nausea, sleep disturbances and apnoeas. The inter-individual variability of these symptoms is quite high, as a select few may feel fine, most will feel some magnitude and combination of the list, and others will be periodically out of commission.

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Performing a carbon monoxide rebeathe test to measure red cell volume and total blood volume with an Andean participant in Cerro de Pasco. This method is technically challenging, and is made more difficult with a significant language barrier.

So, why do we do it? Why do we involve ourselves with the potential suffering at altitude and any additional risks (i.e. transport, illness) kindred to these trips? From my experience, three fundamental elements outweigh the risks and define the success of expeditions and collaborations like Global REACH: the science, the experience, and the team.

Science

1 July 2018: Day 2 at altitude

“MAS FUERTE, MAS FUERTE, yeah Johnny!” Johnny, our first Andean participant is laying on the bed of testing Bay 1, currently practising a handgrip protocol for a vascular study. Johnny already has a venous catheter placed in his forearm and will be shuttled through a screening circuit: ultrasound imaging (cardiac, ocular and vascular), a maximal exercise test and assessment of total blood volume. Our Spanish skills are currently dismal, but we’re managing to compliment the amazing work of our translators to collect a large cardiovascular dataset on approximately 50 Andean participants.

3 July 2018: Day 4 at altitude

Four of us are working in the bloods room to measure total blood volume, hematocrit and viscosity. We knew from previous reports that Andeans would have augmented total blood volumes and hematocrit levels compared to us lowlanders but seeing those bloods ourselves was staggering. ‘A hematocrit of SEVENTY-EIGHT per cent!’ a colleague yelled, astounded. For reference, a lowlander’s normal hematocrit is ~40%. (Fig. 1) An undeniable passion for physiology underpins collaborations like Global REACH.

The energy amongst the group drives impressive productivity and allows us to complete multiple studies in relatively restricted time periods. During the 2016 Nepal Expedition our team conducted 18 major studies, including a total of 335 study sessions in just three weeks at 5,050 m (further to multiple sea level and ascent testing sessions). This high-density data collection is relatively uncommon outside of field work and is only made possible by the vast breadth of technical fluency, specific expertise and research experience amongst the team. The expeditions allow us to not only answer our current questions but further breed a multitude of ideas for future study.

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‘We could answer that one next, Ethiopia 2020? Another Nepal expedition?’ Of course, these expeditions allow us as trainees and investigators to be productive, and to present and publish high-quality data and exciting findings. They strongly contribute to our development and career progression in academia. But what is undoubtedly most important is the greater aim of Global REACH: to understand altitude health on a ‘global’ scale. This collaboration and research ultimately aims to understand why chronic mountain sickness occurs, how different high-altitude communities have adapted (or maladapted) to low oxygen, and what might ultimately be done to improve the health of individuals exposed to acute or chronic hypoxia.

Stay tuned for Part 2 next week, or read the full article in its original version in Physiology News magazine.

Seeing Depth in the Brain – Part II

By Andrew Parker, Oxford University

Stereo vision may be one of the glories of nature, but what happens when it goes wrong? The loss of stereo vision typically occurs in cases where there has been a problem with eye coordination in early childhood. Developmental amblyopia, or lazy eye, can persist into adulthood. If untreated, this often leads to a squint, or a permanent misalignment of the left and right eyes. One eye’s input to the brain weakens and that eye may even lose its ability to excite the visual cortex. If the brain grows up during a critical, developmental period with uncoordinated input from the two eyes, binocular depth perception becomes impossible.

My lab’s work supports a growing tide of opinion that careful binocular training may prove to be the best form of orthoptics for improving the binocular coordination of the eyes. Recent treatment of amblyopia has tended to concentrate on covering the stronger eye with a patch to give the weaker eye more visual experience with the aim of strengthening the weaker eye’s connections to the visual cortex. Now we understand from basic research like ours that there is more to stereoscopic vision than the initial connection of left and right eyes into the primary visual cortex.

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Figure 2: Ramon y Cajal’s secret stereo writing, see Text Box

Secret Stereo Writing. The great Spanish neuroanatomist Ramon y Cajal developed this technique for photographically sending a message in code. The method uses a stereo camera with two lenses and two photographic plates on a tripod at the left. Each lens focuses a slightly different image of the scene in front of the camera. The secret message is on plate B, whereas plate A contains a scrambled pattern of visual contours, which we term visual noise. The message is unreadable in each of the two photographic images taken separately because of the interfering visual noise. Each photograph would be sent with a different courier. When they arrive, viewing the pair of photos with a stereograph device as in Figure 1, the message is revealed because it stands out in stereo depth, distinct from the noisy background. Cajal did not take this seriously enough to write a proper publication on his idea: “my little game…is a puerile invention unworthy of publishing”. He could not guess that this technique would form the basis of a major research tool in modern visual neuroscience.

Our lab is investigating the fundamental structure of stereoscopic vision by recording signals from nerve cells in the brain’s visual cortex. One of the significant technical developments we use is the ability to record from lots of nerve cells simultaneously. Using this technique, I am excited to be starting a new phase of work that aims to identify exactly how the visual features that are imaged into the left eye are matched with similar features present in the right eye.

The neural pathways of the brain first bring this information together in the primary visual cortex. Remarkably there are some 30 additional cortical areas beyond the primary cortex, all in some way concerned with vision and most of them having a topographic map of the 2-D images arriving on the retinas of the eyes. The discovery of these visual areas started with Semir Zeki’s work in the macaque monkey’s visual cortex. Our work follows that line by recording electrical signals from the visual cortex of these animals. To achieve this, we are using brain implants in the macaques very similar to those being trialed for human neurosurgical use (where implants bypass broken nerves in the spinal cord to restore mobility).

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Figure 3: A very odd form of binocular vision in the animal kingdom. The young turbot grows up with one eye on each side of the head like any other fish, but as adulthood is reached one eye migrates anatomically to join the other on the same side of the head. It is doubtful whether the adult turbot also acquires stereo vision. Human evolutionary history has brought our two eyes forward-facing, rather than lateral as in many mammals, enabling stereo vision.

My lab is currently interested in how information passes from one visual cortical area to another.  Nerve cells in the brain communicate with a temporal code, which uses the rate and timing of impulse-like events to signal the presence of different objects in our sensory world. When information passes from one area to another, the signals about depth get rearranged. The signals successively lose features that are unrelated to our perceptual experience and acquire new properties, corresponding closer to perceptual experience. So, these transformations eventually come to shape our perceptual experience.

In this phase of work, we are identifying previously unobserved properties of this transformation from one cortical area to another. We are examining how populations of nerve cells use coordinated signals to allow us to discriminate objects at different depths. We are testing the hypothesis that the variability of neural signals is a fundamental limit on how well the population of nerve cells can transmit reliable information about depth.

To be specific, we are currently following a line of enquiry inspired by theoretical analysis that identifies the shared variability between pairs of neurons (that is, the covariance of neural signals) as a critical limit on sensory discrimination. Pursuing this line is giving us new insights into why the brain has so many different visual areas and how these areas work together.

It is an exciting time. We still need to determine whether our perceptual experiences are in any sense localised to certain regions of the brain or represent the activity in particular groups of neurons. What are the differences between types of neural tissue in their ability to deliver conscious perception?

There are many opportunities created by the newer technologies of multiple, parallel recording of neural signals and the ability to intervene in neural signaling brought by the use of focal electrical stimulation and optogenetics. By tracking signals related to specific perceptual decisions through the myriad of cortical areas, we can begin to answer these questions. The prospect of applying these methods to core problems in the neuroscience of our perceptual experience is something to look forward to in the forthcoming years.

Seeing Depth in the Brain – Part I

By Andrew Parker, Oxford University

The Physiological Society set up the annual, travelling GL Brown Prize Lecture to stimulate an interest in the experimental aspects of physiology. With predecessors such as Colin Blakemore and Semir Zeki, following in their footsteps is a tall order. They are not only at the very top scientifically but also superb communicators.

My lecture series on stereo vision has already taken me around the UK, including London, Cardiff, and Sheffield. I’ll be at the University of Edinburgh on 15 November and Oxford University on 23 November. It’s a nice touch that GL Brown’s career took him around the country too, including Cambridge, Manchester, Mill Hill and central London, before he became Waynflete Professor in my own department in Oxford. The other pleasurable coincidence of giving lectures on stereo vision this year is that there is a 50th anniversary since fundamental discoveries were made about how the brain combines the information from the two eyes to provide us with a sense of depth.

In his 1997 book How the Mind Works Steven Pinker wrote, “Stereo vision is one of the glories of nature and a paradigm of how other parts of the mind might work.” I can’t claim to have written this inspiring sentence myself, but I can at least claim to have chosen stereo vision as my field well before Steven Pinker wrote his sentence.

Stereo vision is, in a nutshell, three-dimensional visual perception. It is the use of two eyes in coordination to give us a sense of depth: a pattern of 3-D relief or 3-D form that emerges out of 2-D images arriving at the left and right eyes. These images are captured by the light-sensitive surface of the eye called the retina. Stereo vision gives us the ability to derive information about how far away objects are, based solely on the relative positions of the object in the two eyes.

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Figure 1: “The stereograph as an educator,” illustrating the virtual reality technology of the Victorian era.

The Victorians amused themselves with stereo vision (see Figure 1). Virtual reality is our modern day version of this, but what comes next? The next generation will probably enjoy “augmented reality” rather than virtual reality. With augmented reality, extra computer-generated imagery is projected onto objects in the real world. The aim is to create a perceptual fusion of real objects with virtual imagery. For example, in one prototype I have seen, surgeons perform their operations with virtual imagery (acquired with diagnostic imaging devices) superimposed upon the surgical field in the operating theatre. Needless to say, this places much higher demands on the quality and stability of the virtual imaging systems.

What causes people like Pinker, who are outside the field, to get so excited about stereo vision? Partly it’s just the experience itself. If you’ve been to the 3-D movies or put on a virtual reality headset, you will have the sense of stereoscopic depth. It is vivid and immediate. The other thing that excites Pinker is the way in which the brain is able to create a sense of a third dimension in space out of what are fundamentally two flat images. As a scientific problem, this is fascinating.

We also see parallels between stereo vision and how other important functions of the brain are realised. One straightforward example of that is visual memory. Gaining a sense of stereoscopic depth from two images (left and right) requires matching of visual features from one image to another. Remembering whether or not we have seen something before requires matching of a present image to a memory trace of a previously seen image. Both processes require the nervous system to match visual information from one source to another.

Another aspect that Pinker is highlighting is the way in which the two flat images in stereo are fused to form with a new perceptual quality, binocular depth. A great deal of spatial perception works this way. One obvious example is our ability to use the two ears in combination to form an impression of sound localised in space, based just on the vibrations received by the left and right ear canals.

What is the world like without stereo vision? While you can partly experience this by placing an eyepatch over one eye (try playing a racket sport or carefully making a cup of tea), the difference is most strongly highlighted by the very rare cases when stereo vision appears to have been lost but is then recovered. Susan Barry, professor of neurobiology at Mount Holyoke College, was stereoblind in early life but eventually gained stereo vision with optometric vision therapy.

In a New Yorker article by Oliver Sacks (Stereo Sue, A Neurologist’s Notebook, June 19 2006) Barry describes her newly acquired perception of the world. “Every leaf seemed to stand out in its own little 3-D space. The leaves didn’t just overlap with each other as I used to see them. I could see the SPACE between the leaves. The same is true for twigs on tree, pebbles on the road, stones in a stone wall. Everything has more texture.”

Check back next Wednesday for Part II of Andrew Parker’s blog on stereo vision.

I am bionic, I have aids in both ears: A Physiology Friday poem

By Simone Syndercombe, age 13, Newminster Middle School

I am as deaf as a post; don’t you see,

That’s why hearing is of interest to me.

Pin back your pinna and I will begin,

To tell you how sounds gets from out to within.

When my mum shouts with intention to berate,

Her speech makes the air from her mouth oscillate.

Hitting the pinna the shape does enhance,

The sound which is high pitched, to further advance.

Down through my ear canal, hitting the drum,

The sound is transferred into mechanical vibra-tion!

The eardrum is attached to a bony chain of three,

The malleus, the incus and the stapes, of me.

They act like a lever, enhancing the sound big,

Transferring the signal from middle to inner ear rig.

Through the oval window, the stapes does conduct,

Sound to the snail-shaped cochlear duct.

In this fluid-filled spiral are sensory cell hairs,

Attached to the basilar membrane, which cares,

Whether amplification or attenuation is desired,

Dampening or boosting before the auditory nerve fired,

Transferring the message to brainstem from ear,

The auditory nerve ensures that we can all hear.

I am bionic; I have aids in both ears,

As I have great difficulty hearing my peers.

Remember the mechanisms this poem’s about.

For I’m not ignoring you, you just need to shout!

Hearing is fascinating, I hope you’ll agree.

And that is why hearing is interesting to me.

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The First Mars Marathon: Part 3

Martian nutrition: How runners will fuel

Carb-loading for the Red Planet marathon might prove more difficult than simply gorging on a pre-race pasta dinner. Since they will be shivering and burning a lot more calories not only during, but before the race, runners will simply have to eat more on Mars during the pre-race period to fully saturate their muscles with glycogen.

Just getting plates of pasta to Mars will be a major issue. After years in transit, many of the nutrients in any food shipped to Mars will have been lost, and deep-space radiation will have degraded much of a food’s chemical and physical structure. Preparing and shipping food to Mars for the runners to eat requires special methods. Anyone care for high-pressure processed, microwave sterilized, freeze-dried spaghetti and meatballs…anyone?

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Use of critical fuels such as carbohydrate and fat will drastically increase on mars due to the extreme cold

Mid-race nutrition is equally important. As stated earlier, the drastically cold temperatures will result in a higher rate of glucose use and glycogen depletion, so the runners will need to fuel more often to keep glucose stores elevated in the face of increased use of these from shivering, coupled with the metabolic demand of running. Marathoners, who rely heavily on their glycogen stores into the later miles of the race will need to ingest glucose during the race at a rate exponentially higher than the recommended 25-60 grams per hour to avoid hitting the dreaded wall around mile 20 of the Red Planet marathon. This drink will likely have to be specially formulated with a higher glucose content.

Authors of a 1998 paper in Experimental Physiology provide evidence that providing a drink containing 15% carbohydrate was able to maintain blood glucose levels better than one containing just 2% during a cycling test to exhaustion (1). For this reason, Martian aid stations will need to occur at regular intervals and provide runners with carbohydrate-rich gels, drinks, or tasty freeze-dried space snacks.

What they’ll wear

Until we evolve into actual Martians, humans won’t get away with running unprotected on the surface of Mars. For now, technology will prove vital to success as runners on this new planet. Newly minted Martian sports scientists and gear technologists will be recruited to design a top of the line marathon-specific spacesuit.

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Theoretical concept of the Mars runner suit. Source: News.mit.edu

This suit will provide a sealed, pressure-controlled environment, help maintain some warmth and control body temperature, riding a fine line between protection and optimal range of motion. A protective suit is necessary: in the low atmospheric pressure environment of Mars, bodily fluids would boil. This is known as the Armstrong limit of pressure, which Mars sits well below.

Additionally, runners will develop severe impairments in blood pressure maintenance due to the reduced atmospheric pressure. This drastic reduction in blood pressure was demonstrated in a Journal of Physiology study from 2015 (2). Studying astronauts on the International Space Station, researchers noted a reduction in blood pressure of 8-10 mmHg, mainly due to central volume expansion.  The marathon gear will resemble something of a wet suit– a design which is able to solve the low-pressure problem by using super tight wrapping  (instead of gas-pressurization, it uses mechanical counter-pressure) (3). This leaves the body mobile. Wrapping the lower limbs in this counter pressure “fabric” will allow full range of motion at the ankles, knees, and hips,

The suit will require an enclosed helmet with breathing apparatus for runners to get their oxygen which is lacking in the Martian environment and dispense of the large amount of atmospheric as well as metabolically produced CO2. But don’t even think about attempting a snot-rocket.

Additionally, features of the suit crucial to completing our space-race might include an airtight hole in the mask so that runners can ingest their mid-race fluids and gel packs.

One final, and perhaps most vital feature will be the shoes. Just as elite runners have custom shoes designed to their unique gait pattern and foot size, Mars marathoners will need footwear tailored with the same precision and comfort in mind. As it turns out, the painful condition of onycholysis (separation of the finger/toe nail from the nail bed) is not just a problem among ultra-endurance athletes, but astronauts too. Ill fitting gloves combined with the intra-suit pressure can spell disaster (and pain) for anyone carrying out activities in space, and this would surely apply to the feet as well. After 26 miles of running in cramped space-boots, it can only be expected that runners might lose one or more toenails. To prevent this, it will be necessary for runners to have Mars boots fit to their particular foot size, strike, and biomechanics.

Can They Do It?

Just as Opportunity Rover completed its own Red Planet marathon, so too will humans eventually cover 26.2 miles on foot over the dusty red surface of the fourth planet from the Sun.

Will it be fast? Probably not – but let’s hope we break the current standing record of 11 years, 2 months. Evolving a new, skipping gait required for efficient running on Mars will take some time, just as did the adaptation of lower limbs and body structure of Australopithecus to that of the modern Homo erectus, a body ideally formed for endurance running. Tendons and ligaments will have to adjust to the new microgravity environment, and it will take time for muscle fibers to regain their strength and capacity. The deconditioning of the cardiovascular system (due to fewer hemoglobin molecules, reduced ability to both supply and utilize oxygen, and decline in heart and lung function) will take some time to adapt to. Along with the various environmental factors (extreme cold, hypoxia, and dangerous levels of radiation), runners will certainly have a slow marathon debut.

We will eventually design equipment and training protocols that allow us to traverse 26.2 in record times on Mars. Remember, the first marathon run by Pheidippides resulted in his keeling over in death upon arrival. Since then, we have perfected running tactics, advanced our knowledge of performance, and unlocked human physiology such that it is now possible for man to run 26.2 miles at an astonishing 4 minutes and 41 seconds per mile, something once thought impossible.

Perhaps, some day, the elusive 2-hour barrier will be broken, not on a curated and well-paced course in Italy, but near Endeavor crater, some 54.6 million kilometers away.

References:

  1. Galloway et al. The effects of substrate and fluid provision on thermoregulatory, cardiorespiratory, and metabolic responses to prolonged exercise in a cold environment in man. Experimental Physiology. 81 (1998); 419-430
  2. Norsk et al. Fluid shifts, vasodilatation, and ambulatory blood pressure reduction during long duration spaceflight. The Journal of Physiology 593.3 (2015); 573-584
  3. Shrink-wrapping spacesuits. Jennifer Chu, MIT News Office. September 18, 2014. http://news.mit.edu/2014/second-skin-spacesuits-0918