Extremely lightheaded,exhausted..have pots.current resting hr went from 45 sitting to 80 standing & stayed around 75 after 1 min. causes?what can help

POTS means: positional orthostatic tachycardia syndrome. That means your heart rate increases when you stand up! The cause is your disease. Autonomic dysfunction. You need to establish with an experienced health care provider as the treatment needs to be individualized and is not cut and dry. Electrophysiologists are specially trained and experienced with this. Seek one out.