it can be due to
high blood pressure, low
blood pressure including bleeding disorders causing anemia, heart diseases like arrhythmias, attack, cardiomyopathy, medications like blood pressure drugs , antidepressants, metabolic disorders like hypoxia, hypoglycemia, dehydration. in women, internal bleeding or hemorrhage, anemia, infections, endocrine disease like thyroid, pituitary gland and adrenals, allergies may cause wheezing, low blood pressure, can trigger sinusitis and resulting dizziness.