I have lhermitte's that gets worse with exercise. neuro says its not ms (clear mris/eval). can other nerve problems get worse with exercise?

L'hermitte's : Sounds neurogenic by your use of the term. Cervical radiculopathies, brachial plexus problems, chiari malformation, syrinx, can all cause similar complaints. I assume they were also ruled out by neurologist. Muscles that attach to occipital for thoracic origin or scapular origin can cause this "lightning" like symptom with movement.

Generic answer: Yes, increased body temperature, fatigue, infection, exertion, all could make central and peripheral nerve symptoms worse. Regarding your "Lhermitte's", have you had a series of blood studies to assess other etiologies, such as B-12 or Lyme issues??