Dysautonomia, also known as autonomic dysfunction, is a group of disorders that affect the autonomic nervous system (ANS). Many people with Ehlers-Danlos syndromes (EDS) or hypermobility spectrum disorders (HSD) also have a type of dysautonomia. Many people with dysautonomia experience blood pooling, which occurs when blood collects in the legs and hands rather than being pumped back to the heart. Compression clothing is tight–fitting clothing that can help reduce blood pooling by pushing blood