Provided are a method for strengthening blood vessels with extreme ease and a compression and decompression control system used in implementing said method. A compression and decompression control system (1) is provided with belts twined around a specific portion of a user's limbs and configured so as to apply a compression force to the specific portion, and a control device for controlling the compression force applied to the specific portions by the belts. The control device controls the compression force applied by the belts so as to alternate repetition between a compression operation for applying a predetermined compression force to the specific portions and a decompression operation for entirely removing the compression force applied to the specific portions by the compression operation. The repetition of the compression operation and decompression operation increases the nitric oxide produced by the vascular endothelial cells of the user's blood vessels, thereby strengthening the blood vessels.
