I have noticed several posts on this website, especially in this section, regarding unexplained, complex symptoms. Most often, I have read complaints associated with rapid heart rate, dizziness, fatigue, and exercise intolerance. If you are struggling with such symptoms, please look into Postural Orthostatic Tachycardia Syndrome (POTS). It is a very unheard of autonomic nervous system disorder that prevents the body from being able to adjust to the pull of gravity. Given the many functions of the nervous system, symptoms of this illness are very widespread and vary from person to person. Most doctors are not yet aware of this condition, and the most common medical tests fail to prove anything is wrong, for those affected appear to be completely normal and healthy. The reason I joined this site is to spread awareness and try to help others. I, and thousands more I have talked to along the way, went undiagnosed for many years. My goal is to decrease the number of people who suffer for so long without answers or proper treatments. I could go on and on, but I will spare you. Just, please, keep this information in mind, and feel free to message me with questions or comments. I have lots to share if you are interested or concerned.Thank you, and best wishes,