“In this case, exercise is very effective,” said Lori L. Ploutz-Snyder, dean of the University of Michigan’s School of Kinesiology and former chief exercise officer at NASA’s Johnson Space Center in Houston. Scientists, too, are new to research.
But there is a problem! To faithfully recreate low-gravity training, we need to run straight to the wall like a cartoon Roadrunner and do weight training on the bed. With a few tweaks, though, an astronaut’s daily exercise routine can work here on Earth and help us develop our own extraordinary fitness abilities.
Why astronauts need to exercise
Space travel is hot right now as NASA’s newly launched Orion spacecraft orbits the moon, the International Space Station continues its long-duration Earth orbit and private rocket companies offer overpriced tours of the stars.
Unfortunately, our bodies are not well suited for space. In microgravity, muscles and bones cannot bear the weight and atrophy rapidly, and cardiovascular fitness plummets.
“Without regular exercise, we lose a lot of muscle mass and bone density,” says Jessica Meyer, a scientist and astronaut who worked as a flight engineer on the International Space Station.
To stem this decline, NASA added exercise equipment to the space station in the 1990s, and astronauts began dutifully exercising slowly and strenuously for several hours a day, pacing themselves to avoid injury and fatigue. But their muscles and stamina still atrophy.
So, in the early 2010s, Ploutz-Snyder and her science colleagues at NASA started thinking about intensity. Until then, exercise science has shown that short bouts of intense exercise build strength and endurance.
Scientists wondered, would this type of short, high-intensity exercise be effective and safe in space? To find out, they asked 34 Earthlings to go to bed and stay there non-stop for 70 days.
Testing HIIT Workouts in Bed
Head-down bed rest is the best scientific simulation of space travel, and it’s also the most disturbing. During the head down tilt bed study, people lay down day and night, On a bed inclined at 6 degrees, their head is facing the floor and their feet are angled upwards. Fluid rushes to their heads, as they would in zero gravity, and muscles and stamina atrophy.
During early head-down-tilt bed rest, the once-healthy volunteers’ physiques actually quickly transformed into mucus — their muscles softened and contracted, similar to what they’d seen after spending months in space.
But Ploutz-Snyder and her colleagues hope that the right exercise program can keep bedridden volunteers fit, and if so, in space. So their engineers mounted treadmills sideways on the wall to simulate running in zero gravity, brought in bed-ready bikes and free weights, and had some of their volunteers work out on their backs almost every day, from a few hours to a few hours. From minutes to minutes. One hour.
As a control, the others were completely sedentary. (All volunteers, aged 24 to 55, passed medical and psychological screenings before the study began and were paid for their participation. No one dropped out.)
The exercisers’ six-week workouts centered around what the researchers call “fluctuating periodization,” meaning they performed high-intensity interval training of varying lengths on some days, while on other days they lifted weights and performed Some cardio training.
In finer detail, volunteers performed 3 high-intensity interval sprints per week on a lateral treadmill (lying on side, mid-air, strapped to the ceiling). Once a week, the interval consisted of eight 30-second all-out sprints; another day of six two-minute intervals; and on the third day, four four-minute intervals, all with a short rest between sprints.
Every few days, the volunteers rode a stationary prone bike for about 30 minutes while in bed at a brisk pace.
Later in the day, they lift weights on the bed, grunting through squats, leg presses, heel raises, and leg bends, using enough weight that they can barely do 8 to 12 reps.
The program is calibrated to stress and strengthen the cardiovascular system and large lower body muscles in the shortest possible time, Ploutz-Snyder said.
The results showed that the prone training was successful. The exercisers retained most of their muscles and nearly all of their stamina, and suffered few injuries, save for ear infections from sweat running into their ear canals while exercising in bed.
But day after day, The inactive control group became less fit and frail throughout the 70 days of the study. After the study, the scientists put them on a separate 11-day exercise and rehabilitation program.
“To me, the most compelling part of the story is that exercising an average of 1 hour a day protects people from being in bed 23 hours a day,” Ploutz-Snyder said. “There is no drug that does that. “
With the data in hand, she and her colleagues then convinced NASA to try the project in space. Back then, in the mid-2010s, astronauts were exercising as much as 2.5 hours a day, nearly all of it at a moderate pace. Some of them now start a new exercise program of running or cycling with short, fast intervals 3 times a week, and lifting weights hard but fast on other days, while also jogging or space biking for about 30 minutes. Their weekly exercise time was cut by more than half. (The ISS astronauts have continued to engage in high-intensity and moderate-intensity exercise since the study ended, albeit in different combinations.)
Meir, who spent 205 days in space during her 2019 and 2020 missions to the International Space Station, praised her workouts there. “Exercising on the ISS is a very important part of our daily lives,” she said.
Lessons from Exercising on Earth
The astronauts in the study returned to Earth with most, though not all, of their stamina and strength intact.
Their losses and gains, Ploutz-Snyder said, are a lesson for the rest of us. Physiologically speaking, sitting for long periods of time is no different than floating in space. When we sit, our muscles, heart, and lungs idle, and if this idleness continues, they lose function.
So get up and walk, says Ploutz-Snyder. Any activity is better than none. But for an efficient, effective workout routine, try scientifically-tested workouts in space, not in bed, she says. Use a bike or treadmill (located on the floor, not a wall) or walk uphill at high speed. If this seems daunting, do interval training for a few weeks.
Full shows can easily fit into most of our schedules and have suggestive appeal, she said.
“It’s been efficient,” she said, and as a sort of added recognition, “many astronauts have continued with the program after their missions.”
Do you have fitness issues?e-mail YourMove@washpost.com We may answer your questions in a future column.
