Using a chi machine for passive exercise may be helpful in alleviating leg and back pain, detoxifying the lower body, and increasing blood flow, especially for those with limited mobility.
What is Chi Machine?
Invented in Japan in the late 1980s, this is an exercise machine that helps with a particular type of workout called “passive aerobic exercise.” The machine is about the size of a large briefcase, with padded ankle supports on top that oscillates back and forth. To use the machine, you lay down on the floor on your back and prop your ankles up on the supports. When the machine turns on, it sways your ankles and legs back and forth at a set rate of speed. The motion is intended to replicate an exercise move from Japanese martial arts known as “the goldfish” because the movement of the legs resembles the movement of a goldfish’s tail when it swims.
Types of Chi Machines
The original machine is sold around the world by Sun Ancon and is the most popular variety. However, it is also quite expensive, costing $450 or more. Many other companies make chi machines at various price levels, with the cheapest ones starting at around $100. 
More expensive machines may be more durable, and some have additional features, such as variable-speed oscillation, self-timer, and remote controls. If you’re shopping for one, it’s best to do some research and read online reviews, as the quality of these machines can vary significantly.
Benefits of Chi Machines
Many benefits of using a chi machine have been claimed since they were first introduced, including the following:
- Improved blood flow: Throughout the day, especially if sitting or standing for long periods of time, blood flow to and from the legs and feet can be impaired. The goldfish motion of the machine can help to increase blood flow and circulation to the lower half of the body, which can also lead to some of the other benefits listed below. 
- Reduced leg and back pain/swelling: The movement by the chi machine can loosen stiff joints and muscles in the legs and lower back. This motion, in addition to the improved blood flow, can relieve swelling, pressure, and pain in the lower body. 
- Lymphatic system benefits: The lymphatic system helps to cleanse the body and blood of toxins, wastes, diseases, and other undesirable materials by circulating a fluid called lymph, which contains white blood cells, around the body. The oscillation of this specialized machine can improve the circulation of lymph, and therefore help to detoxify the body. This may be especially beneficial for those with lymphatic disorders, such as lymphedema.
- Weight Loss: Exercising with this machine can burn calories at a similar rate to walking, which is especially beneficial for those with limited mobility.
- Stress Reduction: The movement of this exercise device is somewhat like a massage, and can help relax stressed muscles in a similar way, thus lowering your likelihood of injury, and helping to reduce the chronic presence of stress hormones in the body.
It should be noted that while there is a great deal of anecdotal evidence to support these claims, very few hard scientific studies exist on the chi machine. And as always, consult with a medical professional before starting a new exercise routine to prevent injury.