The discomfort of the left side of the body from head to toe may be related to ischemic cerebrovascular disease and poor sleeping posture. 1. Ischemic cerebrovascular disease: Ischemic cerebrovascular disease refers to all kinds of cerebrovascular lesions or blood circulation abnormalities, resulting in brain blood supply obstacles, the corresponding blood-supplying areas of brain tissue due to ischemia, hypoxia and brain tissue necrosis or softening, when the right cerebral hemisphere is involved in the left side of the body can appear discomfort. 2. Poor sleeping posture: when you sleep for a long time and keep the left side lying position, due to the limb pressure, causing the left side of the limb blood reflux is not good, which leads to the left side of the body from head to toe uncomfortable. The left side of the body from head to toe discomfort may also have other reasons, it is recommended to go to the hospital in a timely manner, improve the examination to clarify the cause of the disease, targeted treatment or treatment.