I do crossfit 2-3 times a week mixed with regular bike, recumbent bike, and rowing. It's helped a lot with tachycardia. I don't need meds to be upright . I supposedly have mild classical EDS. My biggest issue is still GI with slow motility and bloating . I have also cut out simple sugars and gluten. I would notice more tachycardia with desserts and sweets. try to eat Lots of protein, cheese, nuts, fruit. Supplements: vit c, coq10, magnesium, vit e, vit d, multi vit, vit b1, vit B5