Low blood pressure can lead to headaches. The main ones are: first, hypotension causes ischemia and hypoxia leading to headache; second, hypotension is too long and serious causing a series of lesions leading to headache. Usually, low blood pressure will cause a decrease in cerebral perfusion pressure, causing insufficient blood supply to the cerebral arteries, and the organic substances provided by the blood flow to the body will be reduced, blood volume will be lowered, and the local tissues of the body will suffer from ischemia and hypoxia, and the small arterial vessels will also spasm, thus causing headaches, dizziness, blackness in front of the eyes and other uncomfortable symptoms, among which migraine headaches appear more often. It may be that low blood pressure leads to vascular lesions in the brain, and a series of pathological relationships with the nerves in the brain, eventually leading to headaches. A normal adult with blood pressure below 90 mmHg for high pressure and 60 mmHg for low pressure measured three times in a row can be called hypotensive. Chronic hypotension is more common and can lead to chest tightness, shortness of breath, dizziness, headache, weakness of the waist and knees, weakness, insomnia and irritability.