by Mary Roach
Leon is part of a NASA-funded bed-rest study at the Flight Analogs Research Unit (FARU) at the University of Texas Medical Branch in Galveston. For decades, space agencies around the world have been paying people rather handsomely to lounge around all day and night in their PJs. That’s how it was presented to Leon, who heard about the gig on one of Howard Stern’s odd-ball-headline roundups: NASA WILL PAY YOU TO LIE IN BED.
For three months, twenty-four hours a day, Leon does not get up—or even sit up—for anything: not to shower, not to eat, not to use the toilet. Bed rest is an analog, or mimic, of spaceflight in that staying off one’s feet causes the same sorts of bodily degradations that weightlessness causes. Most direly, the bones thin and the muscles atrophy. Space agencies study bed-resters to try to understand these changes and figure out how best to counteract them.
Bed-rest studies often assess the helpful (or not) effects of drugs or exercise devices—countermeasures, as they say in aerospace medicine lingo—but the one for which Leon has volunteered is simpler. The researcher is comparing certain changes in men versus women. Leon pauses an episode of Magnum, P.I. on the smartphone that he bought on the Internet with his first check. “So basically, yeah, I’m just deteriorating. And they just want to watch it.” He reports this as cheerfully as someone else might report a promotion or a good night at the blackjack table. Leon has high cheekbones, longish, springy black hair, and an appealing smile.
The human body is a frugal contractor. It keeps the muscles and skeleton as strong as they need to be, no more and no less. “Use it or lose it” is a basic mantra of the human body. If you take up jogging or gain thirty pounds, your body will strengthen your bones and muscles as needed. Quit jogging or lose the thirty pounds, and your frame will be appropriately downsized. Muscle is regained in a matter of weeks once astronauts return to earth (and bed-resters get out of bed), but bone takes three to six months to recover. Some studies suggest that the skeletons of astronauts on long-duration missions never quite recover, and for this reason it’s bone that gets the most study at places like FARU.
The body’s foreman on call is a cell called the osteocyte, embedded all through the matrix of the bone. Every time you go for a run or lift a heavy box, you cause minute amounts of damage to your bone. The osteocytes sense this and send in a repair team: osteoclasts to remove the damaged cells, and osteoblasts to patch the holes with fresh ones. The repaving strengthens the bone. This is why bone-jarring exercise like jogging is recommended to beef up the balsa-wood bones of thin, small-boned women of northern European ancestry, whose genetics, postmenopause, will land them on the short list for hip replacement.
Likewise, if you stop jarring and stressing your bones—by going into space, or into a wheelchair or a bed-rest study—this cues the strain-sensing osteoclasts to have bone taken away. The human organism seems to have a penchant for streamlining. Whether it’s muscle or bone, the body tries not to spend its resources on functions that aren’t serving any purpose.
Tom Lang, a bone expert at the University of California, San Francisco, who has studied astronauts, explained all this to me. He told me that a German doctor named Wolff figured it out in the 1800s by studying X-rays of infants’ hips as they transitioned from crawling to walking. “A whole new evolution of bone structure takes place to support the mechanical loads associated with walking,” said Lang. “Wolff had the great insight that form follows function.” Alas, Wolff did not have the great insight that cancer follows gratuitous X-raying with primitive nineteenth-century X-ray machines.
How bad can it get? If you stay off your feet indefinitely, will your body completely dismantle your skeleton? Can humans become jellyfish by never getting up? They cannot. Paraplegics eventually lose from one-third to one-half of their bone mass in the lower body. Computer modeling done by Dennis Carter and his students at Stanford University suggests that a two-year mission to Mars would have about the same effect on one’s skeleton. Would an astronaut returning from Mars run the risk of stepping out of the capsule into Earth gravity and snapping a bone? Carter thinks so. It makes sense, given that extremely osteoporotic women have been known to break a hip (actually, the top of the thighbone where it enters the pelvis) by doing nothing but shifting their weight while standing. They don’t fall and break a bone; they break a bone and fall. And these women have typically lost a good deal less than 50 percent of their bone mass.
NASA funded the work that led to Carter’s computer models. “But it seems like no one there read our report,” he says. “They have this idea that they can send astronauts up and the bone loss will level off in a few months, but the evidence that has come back doesn’t support that view. If you look at a two-year mission to Mars, it’s kind of a scary prospect.”
SOME BED-REST FACILITIES call their volunteers “terranauts.” At first I assumed this was done to confer a sense of importance to the pursuit, like calling a janitor a sanitation engineer. But the day-to-day existence of the three-month terranaut bears similarities to that of an astronaut orbiting Earth. Each day begins with wake-up music on the speaker system. (It was Metallica* on the space station this morning; “some Beethoven thing” at FARU.) You spend your time confined to a small room, or cluster of rooms, and if you try to go outside, you are in trouble. Privacy is hard to come by. At FARU, closed-circuit cameras are aimed at the beds, so staff can be sure everyone is staying flat. (Subjects are allowed to pull the curtain that surrounds their bed only when they use the bedpan.) Whiners are not a good fit. Leon says he went through an irritable patch at the halfway point of his stay, but that he is “so chipper they didn’t notice.” In the half hour I’ve spent with Leon, I have heard only one complaint. It involved the chicken. “It’s little squares. I want chicken with a bone and skin on it! Don’t give me those cubes.”
Leon excuses himself, because the masseuse is coming. Unlike astronauts, bed-resters get a massage every other day to help with the lower back pain that is a common side effect of taking a load off. Obliviously, doctors used to prescribe bed rest for patients with lower back pain. According to a 2003 article in Joint Bone Spine,* regardless of what ails you, it is almost always a good idea to get out of bed as soon as you can.
Without the weight of a body compressing it, the spine’s curvature lessens and the discs between the vertebrae expand and absorb more water. Astronauts are as much as 2.5 inches taller after about a week in space. (The typical gain is 3 percent of one’s height.) Like children, they will “outgrow” their suits if a “growth” spurt has not been factored in.
AARON F. HAS BEEN “head-down” for eight weeks. (The term refers to the 6-degree tilt of the beds. Since weightlessness causes body fluids to shift to the upper part of the body, so must bed rest.) A large fan by his bed is running at top speed, not to cool him but to mask the noises out in the hall. He’s been feeling trapped, unable to get away from it. Not helping matters: His roommate Tim is still in his “ambulatory period.” He goes head-down in a couple days, but for now he’s allowed to pad around the unit in his slippers and sit cross-legged on his bed, which he is doing now.
A kitchen worker pushes a serving cart into the room.
“The high point of my day!” says Tim. He looks genuinely excited over the prospect of hospital food. Aaron accepts his tray without comment. He props himself on one elbow. It is odd to see people reclining for a meal. It’s a drab, antiseptic take on a scene from the Arabian Nights, men lounging on pillows, eating with one hand.
Tim takes me on a guided tour of supper, pointing with his fork. “We’ve got chicken…”
I think of Leon. “Diced?”
“Diced, yes. You could almost roll them! And over here are carrot coins,…” There is a rapt quality to his speech, as though we were gazing at gold doubloons. “…apple slices, milk, two rolls, Jell-O. I really love the food here.”
Aaron searches for something positive to say. “It’s a good variety.” But is struggling. “Then again, it’s the same variety. We get a lot of fish—”
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“Oh my god.” Tim again. “The fish is amazing!”
Tim reenlisted after his first stint here, a few years ago. A sign on his wall says WELCOME BACK, 9290 in glitter paint borrowed from the pediatric oncology unit next door.
Before I can stop him, Tim slides off his bed to go ask the kitchen staff whether there is an extra dinner for me.
Aaron is antsy and squirmy, alternately bringing his legs up to form an A-frame under the sheets and then stretching them flat again. Like Leon and others I spoke with, he is here because he’s trying to pay off some credit card bills. Bed-rest studies are a modern-day debtor’s prison. It’s not just the amount of money—$17,000 for three months of service—but the limited opportunities to spend it. For three months, there is no rent to pay, no groceries or gas to buy, no bar tabs, no air fares. A bed-rest stint is a way to force oneself out of bad habits. (Though not entirely effective: Internet shopping has made FARU one of the busiest stops on the local UPS route.)
Tim graduated with a business degree and no money with which to start a company. He moved into a Vipassana ashram because he felt a need to ponder his future and because “they feed you, and it’s free!” After much thought and rice, he decided to become an actor. He spent the next four years as “a starving artist, literally,” and then he heard about a study here at FARU. When he finished, he returned to acting, joining a New Hampshire theater troupe doing “children’s Macbeth,” the very thought of which alarms me. When the chance came to re-up at FARU, he took it. These days he’s weighing wildly diverging career options: joining the Houston police force, opening a coin-op laundry, enrolling in Navy officer candidate school, starting a landscaping business, and becoming a motivational speaker. He is having, as he puts it, “a quarter-life crisis.”
According to FARU manager Joe Neigut, 30 percent of the people who sign on to bed-rest studies say they are doing so not only for money, but to be a part of the space effort. As Leon says, “It’s as close as I’m going to get to being an astronaut.” At the very least, the association with spaceflight puts a luster on the undertaking. Knowing this, the staff entreat astronauts to write thank-you messages on 8-by-10 glossies. Every now and then, an astronaut drops by to deliver them in person. Aaron got an in-person visit but does not recall the man’s name. Tim received an autographed photo of Peggy Whitson. (“A total BAMF* astronaut,” he called her.)
Tim is back from the kitchen. There is no extra food for me, and that’s okay. “Did I miss anything?”
“Yuh,” Aaron says. “I moved to the left a bit.”
THE BIGGEST SKELETON at Johnson Space Center belongs to John Charles. Charles is 6 feet 7. When he was ten, he knew he wanted to be an astronaut. His skeleton, as though aware of its fate in space, sabotaged Charles’s dreams by growing past the astronaut height cutoff. Charles got his Ph.D. in physiology and went to work for NASA. It is his job to do what he can to protect the bodies and bones of astronauts.
Charles and I spoke one recent afternoon in the Lyndon B. Johnson Meeting Room in the public affairs building at Johnson’s namesake, the Johnson Space Center. A chaperone from the Public Affairs Office sat quietly in the corner, as though Charles and I might otherwise leap into each other’s arms there amid the plaques and signed proclamations of the Johnson era. Charles must put the public affairs people on edge. He is known for speaking his mind freely and sits high enough on the ladder of command not to worry too much about the consequences.
As on Earth, weight-bearing exercise is the best way to hang on to your bone. In zero gravity, of course, you have to create your weight. The problematic and expensive way to do this is to outfit the space station with a rotating room, a huge, inhabitable centrifuge that spins astronauts outward toward the walls, creating artificial gravity. (Keir Dullea can been seen jogging on one in 2001: A Space Odyssey.) The funky and affordable alternative is to mimic weight by pulling astronauts’ bodies down into a treadmill belt as they jog. Typically this involves a harness and bungee cords and much cursing and chafing. It is not tremendously effective. Bone loss researcher Tom Lang says this kind of device pulls exercisers against the belt with about 70 percent of their bodyweight, a scenario that still translates to “massive bone loss.”
It’s unclear how much exercise helps. “Exercise is probably better than not exercising in space,” says Charles, “but we don’t know how much better, because we’ve never done the experiment.” No one wants to expose a control group to the sort of bone loss that could result from doing no exercise at all. “If you have hundreds of astronauts who’ve done different levels, you can pool them into groups and see that this group did slightly less and it had this effect, and this group used a treadmill, not a bike, and it had that effect. But we don’t have those large numbers. We have one person that used a bicycle and not a treadmill, one person that used a bike and then changed to a treadmill, and the first is a female in her forties and the second is a male in his sixties. All we can do is a sort of grouped average. The grouped average says that we have countermeasures that still are not protecting astronauts as much as we would like them to be protected.” According to Lang, astronauts are coming home from six-month space station stints with 15 to 20 percent less bone than they had when they left.
FARU has lately run a study on vibration as a means of preventing bone loss. Subjects exercised while pulled by elastic cords into a vibrating plate installed at the foot of their bed. It’s the same kind of vibrating plate you see advertised on the Internet with promises to build bone and muscle, trim fat, flatten bellies. I was surprised to find them here. So was John Charles. When I asked him about vibration as a bone-loss countermeasure, he said, “It’s over with. It’s not working.” The FARU consent form notes that the investigator has a “relationship” with the vibration machine. He helped invent it.
Carter, too, was surprised to hear about the vibration study. He says the only promising data came from an animal study in which vibration appeared to speed fracture healing. “But in animals that just had low bone mass, it hardly changed the bone mass at all.”
Vibration has had an enduring quack appeal. Medical journals from 1905 to 1915 are rife with articles on “vibratory massage” and the many things it cures. Weakened hearts and floating kidneys. Hysterical cramp of the esophagus and catarrh of the inner ear. Deafness, cancer, bad eyesight. And lots and lots of prostate problems. A Dr. Courtney W. Shropshire, writing in 1912, was impressed to note that by means of “a special prostatic applicator, well lubricated, attached to the vibrator, introduced to the rectum” he was “able to empty the seminal vesicles of their secretions.” Indeedy. Shropshire’s patients returned every other day for treatment, no doubt also developing a relationship with the vibration machine.
Neither Tim nor Aaron is involved in an exercise study. “Me allowing myself to atrophy is going to be the hardest thing I’ve ever done in my life,” says Tim. Before he began the study, Tim was running three to five miles three times a week. He has a countermeasure plan of his own devising. “I heard a story of a POW in Vietnam.” He pauses for some Jell-O. The spoon clicks against the glass bowl. “He was locked in a cage.” Click-click-click. “Every day he played golf mentally. He improved his golf score by six strokes!” He leans back against his pillow. “So, mentally, I can go on a jog.”
Aaron has been pinching off pieces of dinner roll and listening without comment. He turns to face us. “I’ve been mentally doing squats.” He says he has considered suggesting to NASA that they enlist yoga masters or Buddhist monks to teach astronauts how to train their minds to fight the effects of zero gravity. I’m mentally enjoying the image.
The dinner cart returns, and the trays are taken away. The attendant places Tim’s glass on his table. “You didn’t finish your milk,” she says. Food intake is documented as part of the studies. Students hired to monitor the bed-resters make sure they don’t stuff food under their mattresses or behind the ceiling tiles. (Both have happened.)
“You have to e
at everything,” says Aaron. “They will bring back your little tub of maple syrup and make you drink what’s left in it.”
PEGGY WHITSON HAS lived through the scenario that worries Dennis Carter and John Charles. In this scenario, astronauts who have been weightless in space for months or years, bone and muscle compromised, find themselves in an emergency situation: enduring the G forces of a crash landing, jumping out of capsule hatches, pulling colleagues to safety. For Whitson, as we learned earlier, it came to pass in 2008. She and two crewmates returning from the International Space Station endured a ballistic reentry and a 10 G landing. Sparks from the landing set the grass afire, and crewmate So-yeon Yi injured her back.
I talked to Whitson* about the incident. The day the interview was scheduled, there were technical problems with the phone system. By the time Whitson’s voice came on the line, six of my allotted fifteen minutes were up. I lurched from niceties straight into fire and snapping bones. “Commander, I am a huge admirer. Were you worried that your legs would break when you had to run away from the Soyuz capsule?”
“Nah,” said Whitson. She had more pressing concerns. Breathing during the 8 G’s of reentry, for instance, and not throwing up in front of Kazakh farmers in the field where they’d landed.
On her first ISS mission, Whitson said, she exercised so much that some of her bones were denser* than they were before she left. Her overall loss was less than 1 percent. “I did so many squats that I actually increased some in my hips.” Tom Lang, who has studied the skeletons of ISS astronauts, is not overly reassured by things like this. The returning astronaut’s total bone mass can be very similar to what it was before the mission, but that mass is distributed differently. Most of the regrowth takes place in the parts of the bone needed to support walking. But the parts of the hip that would break in a fall were nowhere near where they had been, leaving women like Whitson vulnerable to fractures in their retirement years.
