BPD and Physical Health: How Are They Connected?

I don't have BPD but my mom does. When she hits her low, she gets very physically sick. Her muscles ache, she gets migraines, and she catches whatever is going around at the time.

When I hit my lows, or even worse, when I feel nothing, my brain fog is staggering. My aches get worse, joints are stiffer. And I cant convince myself to do the things that help.