Other causes are anemia, claustrophobia, GERD,
hypoglycemia or low sugar
and some endocrine problems. Endocrine problems, such as an underactive thyroid (called hypothyroidism), overactive thyroid (called hyperthyroidism), adrenal insufficiency (called Addison's disease), low blood sugar levels, and in some cases, diabetes, may lead to hypotension and hence lightheadedness and an off balance feeling.
Certain types of epilepsies and seizures too can cause similar symptoms.