Future Tense

What Working Out Might Look Like on Mars

Extraterrestrial exercise for former earthlings will require some creativity.

Photo illustrations of two people jogging on treadmills on Mars
Photo illustration by Slate. Photos by Getty Images Plus.

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Imagine going for a jog on Mars. With each step in the reduced gravity, you would fly through the air for just a hair longer than you would have on Earth. Even though your jog includes vistas of the famous red soil, you are, woefully, in a pressure-controlled habitat, hopping around a 200-meter track. Indoor space is at a premium here, as is time outside—Mars does not have a magnetic field, so you have to be careful about your cosmic radiation exposure adding up. Plus, bulky spacesuits take a long time to put on and are awkward to move in. The excursions themselves require planning and approval, and you always have to go with a buddy, for safety. You prefer to go outside only on special guided hikes every week or so. Serious outdoor recreation here is reserved for the extreme-sports minded.

Which you are not. In this thought experiment, you have come to the red planet not as one of the first brave souls, or even a very early pioneer. As NASA astronauts are today, these career space travelers were each carefully selected for their pristine blood pressure and had to become scuba certified in order to advance through the agency’s training so they could complete spacewalks. You arrived a bit later in the game to inhabit a bustling colony the size of a small town. You paid your way, and then some, to help make it possible for a couple of artists and a yoga instructor to join (congratulations, in this hypothetical future you are extremely rich!). In your new home, you exercise to keep from going stir-crazy in your largely indoor life, to bond with other residents (making friends as an adult is tough, even here), and to keep your body from deteriorating in reduced gravity.

Even confined to the indoors, running here has its upsides, namely: You can go faster without getting as tired. As physicist Rhett Allain has explained in Wired, it takes less energy to push up with each step, allowing you to put more force into going forward. Plus, you weigh less. Earthlings can experience some of the ease of reduced gravity running by trying out the AlterG, a special treadmill based on research done at NASA in the early ’90s. The AlterG simulates reduced gravity by strapping joggers into, essentially, a large balloon that can be inflated to support much of a person’s weight, simulating reduced gravity. (The initial NASA idea was to use air pressure to increase weight, so that astronauts in microgravity could run in a more earthly way.)

Currently, the AlterG is mostly available at physical therapy locations to allow people with injuries to run with a lower impact. On our Martian settlement, transplants who had running-related knee pain back on Earth can lace up their sneakers again. But most people won’t notice a huge difference after they start running on Mars. When I tried out the AlterG, set to 40 percent of my body weight as one would experience on Mars, it only took a few minutes for it to feel somewhat normal. When I returned to running with full body weight, on the other hand, it felt like my legs were made of lead.

Still, doing bounding laps around the track is so relaxing that you’ve decided to train for your first half-marathon. You’ve registered for an Earth race, the Popular Brooklyn Half. As the name indicates, it’s tough to get into for most, but you’ll run remotely as an astronaut participant. The practice was pioneered by Sunita Williams in 2007 when she completed the Boston Marathon from the International Space Station, her official bib taped to the front of her treadmill. Your setup will be a little fancier: You’ll run on a treadmill wearing a virtual reality headset that takes you through the course. During uphills, you’ll crank up the treadmill incline; for downhills, a coach will attach a large rubber band–like strap to the front of your body to mimic the feeling you’d get on Earth of being pulled down an incline—as well as provide your bones with a bit of higher-impact exercise to keep them strong.

There are perks to running a long race on a treadmill, Tristan Bassingthwaighte, an architect in Hawaii, can attest to. He lived in a small habitat for a year as part of Hawai’i Space Exploration Analog and Simulation (HI-SEAS) to give scientists an idea of what life on Mars might look like. Though he had never run a race before, a couple of his companions inspired him to train for a marathon in order to have something to do. In a treadmill marathon, you are always within arm’s reach of food for refueling, and friends can “come by with a little plant mister and just spray you down,” says Bassingthwaighte.

Though it’s not your favorite, lifting on Mars will be crucial to keep your bones from weakening in the reduced gravity, especially since you one day hope to head back to Earth. In microgravity, load-bearing bones can lose around 10 percent of their mass over six months. The effect is far less dramatic on Mars, but doctors still recommend lifting regularly—a fact that the workout industry here has seized upon. While you have regular lifting equipment now, in the early days of Martian exploration, before ships were able to lug anything but the essentials across the solar system, astronauts had to get creative. Their workouts were designed around whatever they had available, which included lot of walking back and forth with supplies from the food pantry stuffed in a backpack, as participants in HI-SEAS missions on Earth once did. When you arrive on Mars, the new exercise class craze is an old-school astronaut workout that involves transferring Martian rocks and out-of-commission spectrometers around an obstacle course, to 2040s music.

For real fun, you’ll fill part of your weekend playing Ultimate frisbee, an activity that, even for the brave, is impossible to do outside. As astronaut Stan Love told Science Friday, Frisbees require air flowing over them to stay aloft. Mars’ air is thin, and according to Love, “the frisbee would fall to the ground like a rock, although it would go farther than you might expect for a rock because of the lower gravity.” So for your pick-up game, you play on a field inside the small track. Later, you might head to an aerial yoga class, feeling just a bit more graceful twisting around on a piece of fabric hanging from the studio ceiling that you once did on Earth.

Read more from Future Tense on settling space.

Future Tense is a partnership of Slate, New America, and Arizona State University that examines emerging technologies, public policy, and society.