Fever and lack of energy are related to the infection of the body by bacteria, viruses and other pathogens, such as common cold, flu, tonsillitis, bronchitis, pneumonia and infections in other parts of the body. Due to these diseases caused by fever, the body will be in anaerobic respiratory metabolic state, when the body tissue muscle in a state of hypoxia, lactic acid metabolism increased, the body is in the fight against invasive viruses, bacteria, high energy consumption state, coupled with the corresponding gastrointestinal function will be weakened during this period, appetite becomes poor, eating less, the whole body will be in general weakness, muscle pain symptoms, if this time have If you take cold medicine, because of the antihistamine ingredients contained in it, the influence of these drugs will also make people feel drowsy, weak performance, will appear the above discomfort symptoms. At this time, as long as timely targeted treatment under the guidance of doctors, pay attention to rest, drink more water, as the fever subsides, the above discomfort symptoms will be significantly improved.