If I use a pedal exerciser, my legs need to actively push the pedal. However, if I attach my feet on the machinery pedal, and let the machine rotates, my legs are still moving. I call that "inactive exercise".
Sure, the muscle doesn't work out because I don't spend energy, but the lymph does move in back and forth in it the system. As I know, the immune system needs the lymph to move because that's how white cells can escape the blood vessel to protect the body. Massage is one way to stimulate the movement of lymph.
So, would my immune system (and my health in genera) have equivalent results as it has if I really put my effort to do exercise?