To stay healthy in space, astronauts are scheduled to exercise for two and a half hours per day for six days per week. Most, however, exercise seven days per week. They perform both cardio and resistance exercises to keep their muscles and bones strong.
“The theory was that a more stringent regimen of resistance training and interval aerobic exercise would help the astronauts stay fit while on the space station
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Exercise is the number one health priority in space and it is so important for astronauts to exercise while they’re in space. Bone and muscle will decrease in size and strength, and can reduce an astronaut’s ability to do work because it makes them weak, and the weakened muscles and bones would make walking difficult.
Bone plays an important role as a structure that supports the body and stores calcium. It retains fracture resistance by remodeling through a balance of bone resorption and formation.
In a microgravity environment, because of reduced loading stimuli, there is increased bone resorption and no change in or possibly decreased bone formation, leading to bone mass loss at a rate of about ten times that of osteoporosis. The calcium balance (the difference between intake and excretion), which is about zero on Earth, decreases to about -250 mg/day during flight, a value that increases the risk of kidney stones.
Bisphosphonate is a therapeutic agent that has been used to treat osteoporosis patients for more than a decade, with a proven efficacy to increase bone mass and decrease the occurrence of bone fracture. Meals should be nutritionally balanced with calcium-rich foods (milk, small fish, etc.) and vitamin D (fish, mushrooms, etc.). Limited sunbathing is also important for activation of vitamin D. Physical exercise to increase bone load and muscle training should also be integrated into each person’s daily life.
In microgravity, body fluids are moved around. Fluids such as plasma are lost throughout the body. Plasma is where red blood cells live. Less plasma means there is less blood to carry oxygen to the rest of the body. Exercise, however, has been shown to increase the amount of plasma in the body. Astronauts who exercise make more red blood cells.
Microgravity also brings about another change in something called “orthostatic intolerance. It does so by increasing its heart rate and blood pressure to keep more blood returning to your heart. If you can’t do that, you’ll pass out. With no gravity and less blood volume, astronauts are more prone to fainting. Again, exercise can help increase blood volume and circulation. That helps prevent fainting.
Main Exercises in Space:
In space, astronauts use some of these exercise equipment. Each piece does something different. The exercise equipment is put on raised platforms to reduce the noise the machines make.
1. Cycle Ergometer: This is like a bicycle, and the main activity is pedaling. It is used to measure fitness in space because it’s easy to check heart rate and how much work is being done.
2. Treadmill: Walking or jogging on the treadmill is like walking on Earth. Walking is the single most important way to keep bones and muscles healthy. Because the lack of gravity tends to make people float, harnesses are attached to the astronauts to hold them to the walking surface.
3. Resistance Exercise Device (RED): The RED looks like weight-lifting machines you may see on television. To use it, astronauts pull and twist stretchy rubber-band-like cords attached to pulleys. The RED can be used for a total body workout. From squats and bending exercises for the legs, to arm exercises and heel raises, astronauts can do them all on the RED.
An Astronaut uses the RED equipment on the Space Station in 2003, Credit: NASA
4. ARED (Advanced Resistive Exercise Device): was designed for weightlifting weightless environment; it consists of two evacuated, pistol-driven canisters with a flywheel mechanism. Astronauts can configure the machine to perform exercises like dead lifts, squats, biceps curls, and calf raises.
Anti-gravity Treadmill:
Whalen designed a treadmill that would let astronauts run in a more natural way. The design,patented in 1992, encloses a treadmill and the astronaut’s lower body in an airtight chamber. Lowering the air pressure inside the chamber pushes the astronaut down, simulating gravity. Whereas the ISS’s old treadmill allowed Williams to run on about 60 percent of her Earth weight, Whalen’s treadmill would have allowed her to exercise at her normal Earth weight. That’s important for keeping the muscles and bones healthy for when astronauts get home.
Instead of adding weight to astronauts in space, they used the technology to take the weight off of rehab patients recovering from leg and foot injuries.
The machine uses “unweighting technology” to make you feel up to 80 percent lighter—so if you weigh 100 pounds, you could feel as light as 20 pounds on the treadmill.
CEVIS (Cycle Ergometer with Vibration Isolations and Stabilization System) is the closest thing you’ll get to a stationary bike in space. CEVIS doesn’t have a seat because astronauts can’t sit in zero gravity. (The bike in the image below has a seat for training on Earth.) Instead, astronauts snap their shoes to the pedals and tether themselves to the bike with a seatbelt in order to cycle upright and obtain the aerobic and cardiovascular benefits. They can adjust the workload and change speeds to hit their target heart rates.
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