Sarah 1 May 2018 10:44 am That could very well be… Humidity: that could very well be right. I developed MS first when I was about 24. Twenty years later it became progressive and I was finally diagnosed, but in that intervening time I went to the South of France and Italy several times in hot weather, but was not overly affected by the heat. Of course the weather was not humid. On this humid Isle, hot sunny summer weather even now knocks me out.......................Sarah Completed Stratton/Wheldon regime for aggressive secondary progressive MS in June 2007, after four years, three of which intermittent. Still improving bit by bit and no relapses since finishing treatment.