Presumed to have bfs, why does warm showers make the twitching/fatigue worse and cause consequent feelings of weakness, usually better within 15 min

? Something else: What you are describing is not very commonly reported in BFS. What type of evaluation did you have to make the diagnosis? Fatigue and weakness with being over-heated or hot showers is often reported in patients with MS. If you have been thoroughly evaluated by a neurologist, then no need to pursue that. If not, I would consult with one to see if further testing is indicated.