Bad issues occur to a human physique in zero gravity. Just take a look at what occurs to astronauts who spend time in orbit: Bones disintegrate. Muscles weaken. So does immunity. “When you go up into space,” says Saïd Mekari, who research train physiology on the University of Sherbrooke, in Canada, “it’s an accelerated model of aging.” Earthbound experiments mimicking weightlessness have revealed comparable results. In the Seventies, Russian scientists immersed volunteers in bathtubs lined in a big sheet of waterproof material, 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 delivery to demise, 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 other way up for too lengthy. But as a normal rule, the fixed push of g-force on our physique is part of life that we not often discover.
Or no less than, that’s what scientists have at all times thought. But there may be one other chance: that gravity itself is making some folks 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 is a rogue concept that’s removed from broadly accepted, although one which no less than some consultants say can’t be dismissed outright. IBS is a quite common ailment, affecting as much as an estimated 15 p.c of individuals within the United States, and the signs might be brutal. People who’ve IBS expertise stomach ache and fuel, really feel bloated, and infrequently have diarrhea, constipation, or each. But no precise reason for IBS has been pinned down. There’s proof behind many competing theories, resembling early-life stress, food plan, and even intestine infections, however none has emerged as the only real rationalization. That is an issue for sufferers—it’s tough to deal with a situation whenever you don’t know what to focus on.
Brennan Spiegel, a gastroenterologist at Cedars-Sinai Medical Center, in Los Angeles, has a unique concept: People with IBS are hypersensitive to gravity on account of any variety of elements—stress, weight achieve, a change within the intestine microbiome, dangerous sleep patterns, or one other conduct or harm. 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 informed me. “We’re not really supposed to be lying flat for that long.” The speculation, published late final yr 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. But a part of what makes the speculation so alluring is that it’d embody all the different standard explanations for the illness. “It’s meant to be a new way of thinking about old ideas,” he stated.
So precisely how would somebody’s relationship with gravity get off-kilter? Consider 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 vital bodily capabilities influenced by g-force, resembling blood circulation. Serotonin could cause blood vessels to slim, slowing circulation. It could make sure muscle tissue contract or loosen up. It’s additionally essential to digestion, serving to with bowel perform, eliminating irritating meals, and regulating how a lot we eat. Without serotonin, gravity would flip our intestines right into a “flaccid sac,” Spiegel writes. Because 95 p.c of the physique’s serotonin is produced within the intestine, if ranges spike or plummet from elements resembling stress, then the chemical’s attainable dealing with of gravity can be thrown into chaos, affecting digestion. The outcome, he theorizes, is IBS.
Other components of our physique that reply to gravity will also be in on the issue. We are 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 essential to concern responses, and stress of varied varieties could 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. Sure sufficient, folks with IBS have been proven to have a hyperactive amygdala.
That is hardly something near proof. The thought that this painful and extended situation may very well be a gravity dysfunction is a serious stretch, counting on a renegade interpretation of fundamental biology. “People just think I’m crazy,” Spiegel stated. Many of his fellow medical doctors will not be offered on the thought. The gravity speculation is one other in a protracted parade of unconvincing theories about IBS, Emeran Mayer, a gastroenterologist at UCLA, informed me. He’s heard all of them: “It doesn’t exist; it’s a hysterical trait of neurotic housewives; it’s abnormal electrical activity in the colon.” He added, “I don’t think there’s any other disease that has gone through these peaks of attention-grabbing new theories.”
Spiegel’s concept has clear holes. If a defective response to gravity triggers IBS, says David C. Kunkel, a gastroenterologist at UC San Diego, then you definitely would count on to see increased charges of IBS amongst populations dwelling at sea degree versus at excessive altitudes, the place g-force is barely weaker. But that doesn’t appear to be the case: About 1 / 4 of Peruvians stay excessive within the mountains and most Icelanders stay at sea degree, but each nations have excessive charges of IBS. Likewise, IBS charges seem to lower with age, “which would not be expected if the disease was caused by a constant gravitational force,” Kunkel informed me.
Spiegel is conscious that the gravity speculation has little assist within the area and no proof. But the gravity speculation has some logic behind it. The undeniable fact that the weightlessness of area journey can drastically change the physique lends credence to the concept different shifts in our relationship to gravity might do the identical, says Declan McCole, a biomedical scientist at UC Riverside.
And the intestine could also be significantly delicate to gravity adjustments. McCole has discovered 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 purpose that such a shift might hit the intestine laborious. He’s much less positive of whether or not that hypersensitivity exists. If it does, then why haven’t we recognized any chemical substances that assist deal with gravity, as we’ve for concern or intercourse drive or starvation? That molecule might certainly grow to be serotonin, however proper now there’s no proof.
The gravity speculation actually issues solely whether it is significant for folks with IBS. And that’s not assured. Tying the very actual ache of IBS to such a fantastical concept could appear nearer to mythology than medication, leaving sufferers feeling dismissed or belittled. Or they could throw up their arms in despair and put together for a lifetime of ache: If the immovable drive of gravity is the enemy, then why trouble preventing?
But if there may be some fact to it, then the speculation might additionally present a attainable beginning place for therapies. Some of Spiegel’s solutions are already frequent, resembling weight reduction and drugs that lower serotonin, however he additionally advocates for some gravity-specific therapies. “I do talk about it with my patients,” Spiegel stated. “I recommend certain yoga poses; I recommend tilt tables.” People who’ve IBS might balk at his extra radical concepts, resembling transferring to a better altitude or farther from the equator.
The gravity speculation might by no means be something greater than a speculation. We have a protracted strategy to go earlier than actually realizing whether or not the human physique can develop a hypersensitivity to gravity that may make us unwell, or whether or not a few of us are higher geared up to deal with gravity than others. But the burden 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? And then, why can’t it even be harnessed for good? Mekari and his colleagues lately discovered that mendacity at a six-degree downward angle sped up response instances to cognition checks—pointing to a attainable hyperlink between gravity and government functioning. Antigravity treadmills, which assist astronauts put together for weightlessness, are being studied for the therapy of cerebral palsy, Parkinson’s illness, and sports activities accidents.
All of those unknowns about gravity can really feel haunting. Life on Earth has modified so much since its first varieties appeared about 4 billion years in the past, however by means of all of it, gravity has seemingly remained fixed—maybe the one factor that connects each organism that has ever lived. What if there’s nonetheless a lot we’ve to find out about what it’s doing to us? After all, proper now your physique is dealing with gravity, simply because it has been for each different second of your life. Perhaps it could be weirder if gravity wasn’t doing something to us over time. “Every fiber in our body is straining to manage this force,” Spiegel stated. You don’t must spend 56 days in a bath to determine that out.