Fever (children) A fever is a temperature of 100.4°F (38°C) or above. If your child is not feeling well, you should take his or her temperature because a high fever may need urgent treatment. Excessive sweating Sweating is one of the body’s cooling mechanisms. It is a normal response to heat, exercise, and stress or fear. Some people naturally sweat more than others. Wearing natural fibers, such as cotton, and using an antiperspirant often help to reduce sweating