Unhealthy issues occur to a human physique in zero gravity. Simply have a look at what occurs to astronauts who spend time in orbit: Bones disintegrate. Muscle tissue weaken. So does immunity. “Once you go up into area,” says Saïd Mekari, who research train physiology on the College of Sherbrooke, in Canada, “it’s an accelerated mannequin of getting old.” Earthbound experiments mimicking weightlessness have revealed comparable results. Within the Nineteen Seventies, Russian scientists immersed volunteers in bathtubs coated in a big sheet of waterproof cloth, enabling them to drift with out being moist. In a few of these research, which lasted as much as 56 days, topics developed critical coronary heart issues and struggled to regulate their posture and leg actions.
Weightlessness hurts us as a result of our our bodies are fine-tuned to gravity as we expertise it right here on Earth. It tugs at us from beginning to dying, and nonetheless our intestines keep firmly coiled of their stack, blood flows upward, and our backbone is able to holding up our head. Unnatural contortions can throw issues off: People have died from hanging the wrong way up for too lengthy. However as a common rule, the fixed push of g-force on our physique is part of life that we hardly ever discover.
Or no less than, that’s what scientists have all the time thought. However there’s one other chance: that gravity itself is making some individuals sick. A brand new, peer-reviewed idea means that the physique’s relationship with gravity can go haywire, inflicting a dysfunction that has lengthy been a troubling thriller: irritable bowel syndrome.
This can be a rogue thought that’s removed from broadly accepted, although one which no less than some specialists say can’t be dismissed outright. IBS is a quite common ailment, affecting as much as an estimated 15 % of individuals in the USA, and the signs may be brutal. Individuals who have IBS expertise stomach ache and fuel, really feel bloated, and sometimes have diarrhea, constipation, or each. However no actual reason for IBS has been pinned down. There’s proof behind many competing theories, akin to early-life stress, eating regimen, and even intestine infections, however none has emerged as the only real clarification. That could be a downside for sufferers—it’s troublesome to deal with a situation once you don’t know what to focus on.
Brennan Spiegel, a gastroenterologist at Cedars-Sinai Medical Heart, in Los Angeles, has a unique thought: Individuals with IBS are hypersensitive to gravity on account of any variety of components—stress, weight achieve, a change within the intestine microbiome, unhealthy sleep patterns, or one other habits or damage. The concept got here to him after watching a relative confined to a nursing-home mattress develop traditional signs of IBS. “We’re upright organisms,” he instructed me. “We’re probably not purported to be mendacity flat for that lengthy.” The speculation, published late final 12 months in The American Journal of Gastroenterology, is simply that, a speculation. Spiegel hasn’t performed any experiments or affected person surveys that time to a “mismatch” in our physique’s response to gravity as the reason for IBS, although the mechanics are all based mostly in agency science. However a part of what makes the idea so alluring is that it’d embody the entire different standard explanations for the illness. “It’s meant to be a brand new mind-set about outdated concepts,” he mentioned.
So precisely how would somebody’s relationship with gravity get off-kilter? Take into account serotonin, a chemical that carries messages from the mind to the physique. Spiegel sees serotonin as an “anti-gravity substance” due to the position it performs in so many essential bodily features influenced by g-force, akin to blood stream. Serotonin may cause blood vessels to narrow, slowing circulation. It could actually make sure muscular tissues contract or relax. It’s additionally essential to digestion, serving to with bowel perform, eliminating irritating meals, and regulating how a lot we eat. With out serotonin, gravity would flip our intestines right into a “flaccid sac,” Spiegel writes. As a result of 95 percent of the physique’s serotonin is produced within the intestine, if ranges spike or plummet from components akin to stress, then the chemical’s potential dealing with of gravity could be thrown into chaos, affecting digestion. The consequence, he theorizes, is IBS.
Different components of our physique that reply to gravity can be in on the issue. We’re hardwired to react negatively to conditions during which the pull of gravity would possibly hurt us; stroll to the sting of a cliff and your physique will inform you one thing. The amygdala in our mind is vital to worry responses, and stress of varied varieties may cause it to enter overdrive. Spiegel thinks that when stress taxes the amygdala, an individual begins overreacting to potential threats, together with gravity. The digestive points that make up IBS are a manifestation of that overreaction. Certain sufficient, individuals with IBS have been proven to have a hyperactive amygdala.
That’s hardly something near proof. The thought that this painful and extended situation might be a gravity dysfunction is a significant stretch, counting on a renegade interpretation of primary biology. “Individuals simply assume I’m loopy,” Spiegel mentioned. Lots of his fellow medical doctors should not offered on the thought. The gravity speculation is one other in an extended parade of unconvincing theories about IBS, Emeran Mayer, a gastroenterologist at UCLA, instructed me. He’s heard all of them: “It doesn’t exist; it’s a hysterical trait of neurotic housewives; it’s irregular electrical exercise within the colon.” He added, “I don’t assume there’s some other illness that has gone via these peaks of attention-grabbing new theories.”
Spiegel’s thought has clear holes. If a defective response to gravity triggers IBS, says David C. Kunkel, a gastroenterologist at UC San Diego, then you definately would count on to see greater charges of IBS amongst populations dwelling at sea degree versus at excessive altitudes, the place g-force is barely weaker. However that doesn’t seem to be the case: A couple of quarter of Peruvians reside excessive within the mountains and most Icelanders reside at sea degree, but each international locations have excessive charges of IBS. Likewise, IBS charges seem to lower with age, “which might not be anticipated if the illness was brought on by a relentless gravitational power,” Kunkel instructed me.
Spiegel is conscious that the gravity speculation has little assist within the area and no proof. However the gravity speculation has some logic behind it. The truth that the weightlessness of area journey can drastically change the physique lends credence to the concept different shifts in our relationship to gravity may do the identical, says Declan McCole, a biomedical scientist at UC Riverside.
And the intestine could also be significantly delicate to gravity modifications. McCole has found that weightlessness made epithelial cells—which line the intestine and cease invaders from getting into the physique—simpler to evade. So if our inside chemistry can change in a method that makes us hypersensitive to gravity, then, to McCole, it stands to motive that such a shift may hit the intestine exhausting. He’s much less certain of whether or not that hypersensitivity exists. If it does, then why haven’t we recognized any chemical compounds that assist deal with gravity, as we’ve got for fear or sex drive or hunger? That molecule could certainly transform serotonin, however proper now there’s no proof.
The gravity speculation actually issues solely whether it is significant for individuals with IBS. And that’s not assured. Tying the very actual ache of IBS to such a fantastical thought could appear nearer to mythology than medication, leaving sufferers feeling dismissed or belittled. Or they might throw up their palms in despair and put together for a lifetime of ache: If the immovable power of gravity is the enemy, then why hassle combating?
But when there’s some reality to it, then the speculation may additionally present a potential beginning place for remedies. A few of Spiegel’s strategies are already widespread, akin to weight reduction and drugs that lower serotonin, however he additionally advocates for some gravity-specific therapies. “I do discuss it with my sufferers,” Spiegel mentioned. “I like to recommend sure yoga poses; I like to recommend tilt tables.” Individuals who have IBS could balk at his extra radical concepts, akin to transferring to a better altitude or farther from the equator.
The gravity speculation could by no means be something greater than a speculation. We’ve got an extended solution to go earlier than really understanding whether or not the human physique can develop a hypersensitivity to gravity that may make us in poor health, or whether or not a few of us are higher outfitted to deal with gravity than others. However the weight of proof is sufficient to make us assume twice earlier than ignoring the concept our physique’s relationship to gravity can go awry—together with these of us not dealing with IBS. If gravity would possibly contribute to IBS, why not different illnesses too? After which, why can’t it even be harnessed for good? Mekari and his colleagues not too long ago found that mendacity at a six-degree downward angle sped up response occasions to cognition assessments—pointing to a potential hyperlink between gravity and government functioning. Antigravity treadmills, which assist astronauts put together for weightlessness, are being studied for the remedy of cerebral palsy, Parkinson’s disease, and sports injuries.
All of those unknowns about gravity can really feel haunting. Life on Earth has modified lots since its first varieties appeared about 4 billion years in the past, however via all of it, gravity has seemingly remained constant—maybe the one factor that connects each organism that has ever lived. What if there’s nonetheless a lot we’ve got to study what it’s doing to us? In spite of everything, proper now your physique is dealing with gravity, simply because it has been for each different second of your life. Maybe it will be weirder if gravity wasn’t doing something to us over time. “Each fiber in our physique is straining to handle this power,” Spiegel mentioned. You don’t have to spend 56 days in a tub to determine that out.
