Celestial Bodies
A 2022 paper by the German Institute for Aerospace Medicine on cardiovascular orthostatic intolerance in astronauts concludes: “In space, even the healthiest of the healthy will experience worsening of performance and health status unless sufficient countermeasures are instituted. These risks comprise consequences of space radiation, isolation and confinement, a hostile and closed environment, the distance from Earth, and altered gravity.” We have known this since the first astronauts landed, some struggling to stand, much less walk, presenting near-identically to an Earthly patient suddenly grounded by dysautonomia — damage or dysfunction in the autonomic nervous system.
Exercise science suggests that this vital regulatory and navigational system can be righted with the right movement. But the body, nicked off kilter, does not often readjust itself without medical intervention. Reductions in left ventricular mass and blood volume have been observed both in astronauts returning from space and patients on bedrest, a cosmic shortcut to the shrunken heart of Grinch Syndrome.
Hypergravity may exceed the compensatory capacity of the autonomic nervous system, messing with the delicate system of baroreceptors (blood pressure), chemoreceptors (blood composition) and the vestibular system (the body’s position in space) that send information to the brain stem to adjust heart rate, cardiac contractility, vascular tone, and renal sodium reabsorption. In zero gravity, weightless fluid and blood cells are distributed to the head and there is a paradoxical reduction in central venous pressure reduction and changes to grey and white volume matter, not dissimilar to those seen in Long COVID patients or other kinds of brain damage. During re-entry, the spacecraft’s rapid deceleration generates 3-5x the additional gravitational stress on the body, raising the heart rate as high as 150bpm, akin to a dysautonomic response to standing still.
In The Calculating Stars, Mary Robinette Kowal’s fictional astronaut heroine, Elma York, one of the few female WWII veteran pilots with enough flight hours to qualify for astronaut training says: “I know people who are afraid of flying who say that the takeoffs and landings are the only hard parts, perhaps because that’s when the act of flying is most apparent….The weight and the sense of momentum press against you and the vibrations from the tarmac hum through the yoke and into your palms and legs.” How the start and end of something (relationships, jobs, travel) have their own momentum.
Science fiction handles this risk in various narrational and experimental ways. Kowal’s moon colony includes a weighted track and gym and mandatory exercise rotations, weaving in commentary on women’s bodies being unfit for adventure or war and the vital but mundane science of space travel that is more akin to keeping house. Kim Stanley Robinson’s Martian-born children grow adaptively lean, metaphors for second generation immigrants outpacing their parents in integration; anti-colonial and environmental arguments against terraforming. In The Expanse series, James S.A. Corey uses it to talk about class segregation: blue collar workers on asteroid belts physically out of place planets; new ethnicities formed around gravitational effects and linguistic isolation.
Aerospace medicine handles it with research, trying to mimic the conditions of space on earthen bodies to better study it and design countermeasures, to cushion the after-shock of reintegration, recognizing that we cannot have viable space travel if all the highly trained and educated astronauts return ruined by gravity. But it remains poorly studied in medicine and the failure rates for autonomic rehabilitation programs are sky-high and under-investigated. The famous Levine program had a 70% drop-out rate in it’s original study. David Putrino’s slower autonomic rehab program, built for and with Long COVID patients, was 60%. Patients are still routinely told they are merely anxious and their symptoms psychosomatic, the problem individual compliance not design.
It was not for lack of trying that I failed out of every physical rehab program I attempted, despite months of bedridden heel slides, clam shells, and leg lifts; Levine-style seated rowing machines and recumbent bicycles. The body inflamed, operating sub-optimally, needs higher caloric input just to function, much less regrow beefcake muscle, and in my ill health I could barely prepare and digest a meal. I vibrated so hard from sympathetic overdrive I shook off pounds like water, tachycardia making even the elevator ride to the gym an endurance event. Lifting my hands over my head or reaching forward for the rowing machine handle was asking my body to deck me to near-blackout. My anaerobic threshold lowered so much my body responded to every session, no matter how lightweight or brief, like I’d run a marathon with no training and the flu.
On Earth, dysautonomia can be triggered by brain injury, viruses, blood loss, pregnancy, birth, bedrest, or a combination of the above. It is, I believe, a critical factor in the Long COVID disease process, not a symptom, and medical interventions beyond physical rehab are key to preventing a degenerative trajectory into severe MECFS where even sitting up in bed can be catastrophic. In a recent study arguing that Long COVID is a kind of accelerated aging, the authors describe the body as lacking the physiological reserves to snap back to homeostasis, both from the original viral stressor and further threats, a possible explanation for why some patients’ conditions degrade from subsequent infections, vaccines, stress, or even exercise.
Most of the medications available for dysautonomia work indirectly, addressing the cardivascular issues that autonomic dysfunction causes, but not the dysfunction itself, in the hopes that lifting the weight off the nervous system will allow it to recalibrate or the patient to exercise their way to stability. But a few (e.g., Ivabradine) are more nuanced and stabilizing, promising not just the temporarily blunted sympathetic response of beta blockers but a potential re-regulation of the neurological cluster that comprises the “second brain” in the heart.
Dysautonomia is also often comorbid with other neurological and immunological disease, neurodivergence, and psychiatric conditions, which many doctors dismiss as an unexplained coincidence or mind-body influence, not a causal link helping explain everything from emotional reactivity to heat sensitivity. In Multiple Sclerosis, it is a byproduct of lesions in the autonomic regulation regions of the brain, responsible for MS’s cardiovascular, thermoregulatory, gastrointestinal, and sleep symptoms. In Parkinson’s, it is one of the early predictatory sign and responsible for common symptoms, including heightened fall risks; potentially key to pathological propagation from the peripheral to the central nervous system. Early evidence, suggests Long COVID patients may also be at heightened risk of neurodegenerative illnesses, echoing data from the Spanish Flu and other viruses.
In neurodivergence and psychiatry, the picture is more complicated and even less well-studied, impaired by medical bias, a historic tendency to hystericize physical ailments in women and trans people, and known cardiovascular and autonomic side effects of many neuropsychiatric medications. Autonomic dysfunction is a predictor of developing schizophrenia and believed to be responsible for heightened cardiovascular risk among patients, but few clinicians have made the link between neurotransmitter-mediated autonomic regulation and emotional regulation in other psychiatric diagnoses or the psychiatric effects of long-term impaired cerebral oxygenation and neuroinflammation, despite evidence that immunological issues are part of why it is so difficult to treat.
A review of 15 studies that measured autonomic modulation in adults with ADHD found “compromised measurements of electrodermal activity, heart rate variability, blood pressure variability, blood volume pulse, pre-ejection period, and baroreflex sensitivity”. Another 55 study review reported high rates of autonomic nervous system dysfunction in adults with ADHD, notably hypoarousal at rest and during “tasks requiring response regulation and sustained attention”.
We treat ADHD with stimulants predominantly, or alpha-androgenic activators that directly impact vasodilation. We tell patients it is to increase a critical shortage of dopamine, but fail to tell them dopamine is critical to blood circulation, that all ADHD meds tug on the complex knot that is the cardiovascular system, that blood flow to the brain and inflammatory markers such as IL-6 are as much a contributor or detriment to attention and memory as dopamine. We tell psychiatric patients the problem is insufficient or too many neurotransmitters (eg: serotonin, noradrenaline), but fail to mention how critical neurotransmitters are in the cardiovascular system, how connected they are to histamine and other inflammatory processes, how much our emotions are impacted by not just the experience of physiological dysregulation but it’s mechanisms, that many SSRI’s are also (intentionally, necessarily) vasoconstrictors or histamine blockers.
“Postflight orthostatic intolerance”, says the Aerospace Medicine study, “could pose major risks when landing on another celestial body”. Certainly, I am still a flight-risk to my own and other bodies, too many months of isolation and confinement, my own hostile environment cooking my brain and atrophying my muscles, how this illness pins you to the bed like hypergravity. I am quicker to retreat to regulate away from environmental inputs and stressors; more overwhelmed still by crowds and conflict. Recently, bedridden scientist Dianna Cowern (@physicsgirl) went live to show a day in her life, her bedroom a kind of space capsule protected from sound and light and touch and company in the hopes that reducing stimulus will keep her condition from worsening.
Ellen Samuels writes, in an essay on crip time: “Disability and illness have the power to extract us from linear, progressive time with its normative life stages and cast us into a wormhole of backward and forward acceleration, jerky stops and starts, tedious intervals and abrupt endings.” While I slowly got used to moving again at an earthly pace the world moved on, and I am still catching up: whole communities, sports leagues, relationships and friend groups, bars and venues, festivals and events, infrastructure and connections, gossip and trends, sprung up on the ground while I was aloft. Unmappable in their formation unless you lived through them, more difficult to enter if you missed the incubation period when people re-emerged into post-vaccine pandemic life desperate for in-person connection.
I still feel alien on Earth sometimes, in my own skin and the company and arms of others. Particularly the unscathed, those miraculously untouched by both the health and economic impacts of the past four years, who did not lose momentum or loved ones, whose lives were enriched by the constraints or unfettered entirely. I don’t always have the energy to wait for someone else to speak up in a conflict, to show up in community regularly, to let the friction of casual proximity re-spark dropped connections. I am more direct, more honest, more bold with the limited time and energy I have, take charge more because I can barely trust my own body in my own hands, much less allow myself to be a passenger princess someone else can pilot.
I calculate and miscalculate every move I make before flying (down a hill, off the handle, in love). I’m still closely monitoring everything, still tinkering with my health like a loving mechanic on a long-haul spaceflight, knowing I don’t have the option of spare parts or ignoring a problem. My body cannot bear the weight of unresolved conflict orbiting me like debris, to have additional drag on decisions to go out. But my brain still moves slower than it should. Weeks or months later I will understand a social situation, comprehend the risks of an action, or connect the dots on a bodily mechanism gone awry, often too late to navigate around it. Elma York, the consummate calculating pilot in Kowal’s Lady Astronaut series says, in a moment of crisis, “without a plane, what was I supposed to do? Math the problem to death?”
I am not out of the woods yet health-wise but I can hike them, steps sweetened with the cautious optimism of multiple days in a row without disaster, blood oxygen tonguing my calves fuller — second hearts swollen with pride, recirculating deoxygenated blood back to the heart by compressing vessels with a firm grip on my feet instead of volatile neurotransmitter triggers. Wading two feet into water is more compressive than medical grade stockings, submerging not unlike accelerating into spaceflight, and I am back in the water swimming laps instead of just floating in space. The dysautonomia rehab program designers were not wrong that the right movement begats improvements, they just underestimated the sometimes permanent damage of false starts without the cushion of parallel treatment and amount of variation in their patient population. I am unlearning my body’s disaster protocol, refreshing the basics of running and moving with ease instead of terror, the good kind of stress that improves instead of degrades the body. I am coming down to Earth, a little more grounded, a little worse for the journey, a stranger still in my own city.
The Impairing Curse is a long-form, serialized experiment in personal essay, science journalism, policy analysis, and poetry. To start at the beginning and read it in order, go to the first essay or read about the aesthetics and labour of illness, and the failures of public health. To support this project, share it online or subscribe. The series is intentionally not behind a paywall, to ensure broad access to patients and timely circulation of information in our evolving public health crisis, but paid subscriptions are welcome.