I agree with the others especially Tony T. who is a pretty savvy tourer. Start slow, build up, and if very hot, start early. Most cyclist push beyond their endurance and their bodies and immune systems breakdown. Immodium is a must. Be careful eating salads and unwashed vegetables. Eating dairy products, for some people, in the heat, is a not advisable. I keep a little first aid kit & a roll of TP with me. I once felt really ill, high fever, after riding in a cold rain, most of the day. I saw a physician and stayed in a motel for several days. When I felt a little better, I began to ride but felt worse, after a while. Although I was disappointed, I had an upper respiratory infection and my attitude was, not this time, there is always another day. So I rented a car, and drove home. The only other time I had difficulty was after the first day of intense heat and 75 miles, I cramped severely in my quads. Some fluids and backing off the mileage, for the next day, was all I needed. If you plan ahead, for such an emergencies, a lot some funds for it, you should be ok.