This is incorrect information. Having POTS does NOT mean that your "heart is not strong enough..." It means your sympathetic nervous system is - to use non-medical terms - out of whack. In medical terms, POTS describes a common form of autonomic dysregulation characterized by excessive tachycardia (your heart beating over 100) upon standing in the presence of orthostatic intolerance. In other words, when you stand up, your autonomic nervous system doesn't send the correct signals quickly enough to tell the blood in your lower extremities to get it back to the heart to be pumped to the brain in a timely manner.. so you may feel light headed or even faint. Let's be careful not to frighten people into thinking , if they have POTS they have a weak heart. That's wrong. Just being deconditioned is often a cause and slowly getting back in shape can turn POTS around. Please see the NIH for correct information on POTS: https://www.ninds.nih.gov/Disorders/All-Disorders/Postural-Tachycardia-Syndrome-Information-Page