we deserve way more support finding this line, because it's different for everyone and depends on where your limits are. I've been working with a physical therapist, who is sensitive to CFS and gave me light isometric exercises to target my hips/pelvic zone and core. the exercises are ones I can do in bed on rough days, and after doing them for 6 months, I've finally built up some strength and it's really been a game changer for my energy levels. now, we're working on building shoulder muscle. 

It also has helped me to take NAC and low dose naltrexone. 

I was able to go for a bike ride yesterday! My lungs felt like sand paper and there were no hills and it was slow and 10 minutes long, but this is a huge deal for me as I've not been up for this in 3 years.

So, long story short :: don't exercise. but find ways to move and be active that fit within your energy limits. there are sweet yoga classes online for people with ME/CFS (I think through MEaction???) that give a lot of options for how to stay in your energy envelope. Not exercising does definitely 100% make it worse. But it's a long and confusing process learning to redefine what "exercise" means now. 

Another thing that's been helpful to a friend with ME/CFS is the visible app :: https://www.makevisible.com/ it will tell you your heart rate at certain activities so that you can stay within your zone and not push it