“Exercise is quite powerful under these conditions,” said Lori L. Ploutz-Snyder, dean of the University of Michigan School of Kinesiology, who was previously a senior exercise scientist at NASA Johnson Space Center in Houston and is co-author of the new research.
But there is a catch. To faithfully recreate low-G workouts, we’d have to run up a wall, like the cartoon roadrunner, and train with weights in bed. However, with a few tweaks, astronauts’ daily exercise routines can work on Earth and help us develop our own off-world fitness.
Why do astronauts need exercise?
Space travel is all the rage right now, as NASA’s newly launched Orion spacecraft circles the moon, the International Space Station continues its long-term Earth orbit, and private rocket companies offer cheap sightseeing tours. exorbitant towards the stars.
Unfortunately, our bodies do not adapt well to space. In microgravity, muscles and bones are unbearable and wither quickly, and cardiovascular capacity plummets.
“Without regular exercise, we would lose significant muscle mass and bone density,” said Jessica Meir, a scientist and astronaut who served as a flight engineer on the International Space Station.
Hoping to halt such declines, NASA added exercise equipment to the space station in the 1990s, and astronauts began exercising slowly and laboriously for several hours a day, pacing themselves to avoid injury and fatigue. . But his muscles and fitness still shrank.
So, in the early 2010s, Ploutz-Snyder and his fellow NASA scientists began to consider intensity. By then, exercise science had shown that brief bouts of all-out, strenuous exercise built strength and stamina.
Could that kind of brief, intense exercise be effective and safe in space, scientists wondered? To find out, they asked 34 earthlings to lie down and stay there, non-stop, for 70 days.
HIIT bed workout test
Head-down inclined bed rest is the best scientific simulation of space travel, and the most baffling. During downward tilt bed rest studies, people lie down, day and night, in beds that are inclined six degrees so that their heads point toward the floor and their feet slope up. Fluids rush towards their heads, as they do during weightlessness, and muscle and stamina atrophy.
On initial head-down bed rest, the once-healthy volunteers’ physiques quickly turned, in effect, to goo: their muscles softened and shrank, similar to what you would see if they had spent months in space.
But Ploutz-Snyder and his colleagues hoped that the correct exercise program it could keep bedridden volunteers fit and, if so, could be used in space. Then his engineers set up side treadmills on the wall to mimic weightless running, they brought in bikes and weight machines that could be used in bed and had some of their volunteers exercise almost every day, on their backs, for anywhere from a few minutes to an hour.
Others remained totally sedentary as controls. (All of the volunteers, ages 24 to 55, had passed medical and psychological tests before the study began and were paid for their participation. None dropped out.)
The athletes’ six-times-per-week routine centered on what the researchers called “undulating periodization,” meaning that some days they did high-intensity intervals of varying duration and others they lifted weights and did some aerobic training.
In more granular detail, the volunteers ran on the lateral treadmill three times per week through high-intensity intervals (while lying on their side, in the air, hooked to the ceiling). Once a week, the intervals consisted of eight 30-second all-out sprints; another day of six two-minute intervals; and on a third day, four four-minute intervals, all with short rests between sprints.
On alternate days, the volunteers rode stationary bikes upside down in bed at a brisk pace for about 30 minutes.
Later that day, they lifted in bed, grunting through squats, leg presses, calf raises, and leg curls, using weights heavy enough that they could barely finish eight to 12 reps.
The program was calibrated to stress and strengthen multiple aspects of the cardiovascular system and the large muscles of the lower body in the shortest amount of time possible, Ploutz-Snyder said.
The results indicate that the tummy time workouts were successful. The jocks retained most of their muscle and nearly all of their stamina, and sustained almost no injuries other than ear infections caused by sweat entering their ear canals while exercising on the bed.
But day by day over the 70 days of the study, the inactive controls became less fit and weaker. The scientists enrolled them in a separate 11-day exercise and rehabilitation program after the study ended.
“The most compelling part of this story, to me, is that an average of one hour of exercise a day protected people against 23 hours a day of being in bed,” Ploutz-Snyder said. “There is no drug that can do that.”
With the data in hand, she and her colleagues persuaded NASA to test the program in space. At the time, in the mid-2010s, astronauts were exercising up to 2.5 hours a day, mostly at a moderate pace. Now, some of them started the new routine, running or biking for a few minutes in short, brisk intervals three times a week and lifting weights but fast on other days, while also jogging or riding space bikes for about 30 minutes. Their weekly exercise time was cut by more than half. (Since the study ended, astronauts on the International Space Station have continued to mix vigorous and moderate exercise, albeit in different combinations.)
Meir, who was in space for 205 days during the International Space Station missions in 2019 and 2020, praises the effects of his training there. “Exercise on the International Space Station is an incredibly important part of our routine,” he said.
Lessons for exercising on Earth
The astronauts in the study returned to Earth with much, but not all, of their stamina and strength intact.
There is a lesson in both his losses and his gains for the rest of us, Ploutz-Snyder said. Long hours of sitting is no different, physiologically, than floating in space. Our muscles, hearts, and lungs are inactive when we sit, and if that inactivity continues, they lose their function.
So get up and move, Ploutz-Snyder said. Any activity will be better than none. But for an efficient and effective exercise routine, he said, try scientifically proven space training, but not from bed. Use a bike or treadmill (located on the floor, not the wall) or walk briskly up the hill. If it seems daunting, thread interval sessions for a few weeks.
The entire program can easily fit into most of our schedules, he said, and has flirty appeal.
“It’s efficient,” he said, and effective, and as added support, “many of the astronauts continued with the program after their missions ended.”
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