When astronauts blast off into space, they’re leaving behind the comforts of Earth’s gravity—and with it, many of the forces that keep our muscles strong. On Earth, gravity helps us stay grounded, giving our muscles a reason to stay active and engaged. But once astronauts enter the weightless environment of space, things change. Without gravity pulling on their bodies, astronauts don’t have to exert the same physical effort to perform everyday tasks. As a result, without a carefully planned exercise regimen, they could quickly lose muscle mass and strength, which is crucial for their overall health and the success of their mission.
Since I was a child, I’ve been fascinated by the day-to-day lives of astronauts, wondering what it must be like to float in space, surrounded by stars and the infinite blackness. But beyond the wonder of space exploration, there’s a lot to be learned from the way astronauts maintain their health in such an extreme environment. One of the most important aspects of their health is muscle preservation, and it turns out that astronauts undergo serious daily workouts to avoid the devastating effects of muscle atrophy in space.
Why Muscle Maintenance is Critical in Space
In a zero-gravity environment, our muscles no longer need to work as hard. On Earth, simple tasks like standing, walking, and lifting objects require muscle engagement due to gravity’s pull. In space, however, astronauts aren’t using these muscles in the same way. This lack of use leads to muscle weakening, which is problematic for astronauts who need to perform physically demanding tasks like moving heavy objects or even re-entering Earth’s atmosphere safely. Muscle strength and endurance are crucial for their ability to handle the high-stress conditions of space missions, as well as for their health and well-being upon return to Earth.
In addition to muscle loss, astronauts also face the risk of bone density loss due to the lack of gravity. Without the need for bones to support the body’s weight, they become weaker and more brittle over time. As a result, astronauts must also engage in exercises designed to maintain their bone health. Together, these two challenges make it clear why staying physically fit in space is not just a choice—it’s essential for survival and mission success.
How Astronauts Combat Muscle Atrophy
NASA takes muscle preservation in space very seriously. Every astronaut on a long-term mission is required to complete daily workouts to counteract the effects of living in a microgravity environment. These workouts are not optional—astronauts must commit to spending at least two hours each day engaging in physical exercise.
But how do astronauts work out in space? Without gravity to create resistance, traditional forms of exercise like running or lifting weights are not feasible. Instead, NASA has designed a series of specialized equipment and routines that simulate the benefits of Earth-based workouts.
- Treadmills
One of the most common pieces of equipment used on the International Space Station (ISS) is a treadmill. Astronauts strap themselves to the treadmill with harnesses to prevent themselves from floating away. They can then run or walk, getting the cardiovascular benefits they would normally achieve on Earth. The treadmill also provides an excellent opportunity to keep their muscles engaged, as the movement mimics walking or running on Earth. - Resistance Training Machines
Since astronauts don’t have the weight of gravity to help build muscle through traditional lifting, they use machines that simulate resistance. The most well-known of these is the Advanced Resistive Exercise Device (ARED), which allows astronauts to squat, deadlift, and bench press using a system of vacuum cylinders to create adjustable resistance. This exercise machine is essential for preserving muscle strength in the lower body and core, which is critical for daily activities like moving and even just maintaining posture. - Cycle Ergometer
The Cycle Ergometer with Vibration Isolation and Stabilization (CEVIS) is another crucial piece of equipment. It functions similarly to a stationary bike on Earth, but with added technology to help keep the astronaut stable while they pedal. Just like the treadmill, astronauts are strapped into place to prevent them from floating away. The cycling machine provides cardiovascular benefits and also engages the lower body muscles in a way that’s essential for their overall health.
The Importance of Consistency
The key to maintaining muscle mass in space is consistency. Just as on Earth, regular exercise is essential to keeping the body strong. NASA has found that even with two hours of exercise per day, astronauts may still lose some muscle mass—particularly in the legs and back. However, this loss can be minimized with the right combination of workouts and equipment.
Astronauts undergo a carefully designed regimen that mixes cardio with strength training. This combination is critical because while cardio exercises improve endurance, strength training helps preserve and build muscle. In space, these workouts are specifically tailored to target muscle groups that would normally weaken due to the lack of gravity.
The Psychological Benefits of Exercise
Exercise in space isn’t just about muscle preservation; it also has significant psychological benefits. For astronauts who spend months at a time in the isolated environment of the ISS, exercise serves as a way to maintain mental health. Physical activity can reduce stress, improve mood, and help astronauts maintain a sense of normalcy. Given the demanding nature of space missions, staying physically fit is just as important for mental well-being as it is for physical health.
Looking to the Future
As we continue to explore space, especially with upcoming missions to Mars and beyond, exercise in space will only become more important. Future missions may require astronauts to stay in space for extended periods, with physical fitness routines evolving to meet the demands of even more extreme environments. Innovations in space exercise equipment, as well as advances in our understanding of muscle preservation in zero gravity, will likely continue to evolve.
Just as exercise on Earth plays a vital role in human health, the same holds true for astronauts in space. By carefully monitoring and maintaining their physical fitness through innovative techniques and equipment, astronauts can continue to thrive and succeed in the harsh conditions of outer space. And perhaps, with these groundbreaking approaches, we’ll learn a lot about the human body—and what it takes to keep it strong—both here on Earth and in the farthest reaches of space.
