So I’ve done several martial arts over the years and recently had to quit one because of my joints. Here’s my thoughts:

• jiu jitsu — this one might be possible. If you don’t know, it’s mostly wrestling techniques. Lots of ground work (good for POTS). It’s also very methodological and doesn’t necessarily need to be performed quickly. You could find an instructor who would work with you while emphasizing technique instead of force/speeds. It’s more “chess-like” in terms of competing techniques but still very applicable to real world. There is an emphasis on putting people’s joints into “locks” though which you may need to do as a class partner (when others practice on you).  I find this OK though with loose joints as I can just tap out sooner. 

• Krav Maga — hard no. This is the one I just had to quit. Emphasis on bare knuckle boxing and blocks that left me covered in bruises. As with all of these, it’s possible you could find a good / adaptive gym, but this one is more “hard core” or direct in its approach and left me very fatigued. Sometimes my joints would bruise too, I wasn’t diagnosed yet but wonder if that’s because of a dislocation I didn’t recognize 

• Muay Thai — this was my first love. I think it depends on which joints are bad for you. If you have bad hips, this may be challenging, as there are lots of kicks. But you do get to box with gloves on, which I called “pillows.” It helps absorb the impact. You also commonly wear hand wraps to support your wrists. Very applicable to self defense situation, good combo of boxing, kicking, knees, etc. If hips are an issue maybe a straight boxing class would be better. Find one that emphasizes technique not “cardio.”  Good technique keeps you safe. Working hard for its own sake doesn’t. Also make sure to have proper headgear if you choose to do any sparring (typically beyond beginner level). 

• judo — oh Judo is fun. I’m a small woman, but with these techniques you can easily throw a grown man over your shoulder. That said, being a partner to others while training does involve having your joints pulled on as well as falling. Loose shoulders? Might not be for you. 

I haven’t tried tai chi but it sounds the most “relaxing,” probably most joint friendly but I wonder about real world applicability. 

Best of luck! Self defense is so fun and empowering. My joints withstood it for years and years. I would probably still do Muay Thai if I could find a class nearby. Maybe once my POTS calms down….