Or in medical terms, Uhthoff's Phenomena (heat intolerance).
Many people with MS experience a drastic sensitivity to increased body temperature.
Demyelinated tissues in the central nervous system can be very sensitive to even small increases in core body temperature, which results in nerve conduction delays or even conduction block.
This sensitivity can be exasperated by exercise, hot baths, emotion, fatigue, fever, or for me - Summer. Ugh.
Any MS symptom can appear because of this, with the most common being blurring of vision after activity and overall physical weakness.
Avoidance is the best defense (yeah - tell that to my kids).
For now, I'll use my cooling neck tie (so ugly, but really helps), take lots of cold showers, and make room in the freezer for my entire self...
Only two months to go...