1. Physical fatigue: People are overworked and lack sleep due to busy study and work or more physical exercise. Fatigue is due to the accumulation of a lot of carbon dioxide and lactic acid in the blood, or insufficient oxygen supply during sleep. After timely and proper rest, supplement diet and nutrition, it can be recovered.
2. Psychological fatigue: Due to some environmental factors, people are anxious and pessimistic, and they can't vent their worries all day long, which will lead to psychological fatigue over time. You should pour out your troubles to your relatives and friends to make you feel comfortable, and then you can recover through regular diet and physical exercise.
3. Pathological fatigue: The above two kinds of fatigue can be controlled and recovered through the automatic adjustment mechanism of the human body, and some fatigue is a precursor signal of major diseases, indicating that hepatitis, tuberculosis, hypertension, arteriosclerosis, anemia and cancer are coming soon or already.
4. Seasonal fatigue: As the saying goes: "Spring is sleepy and autumn is lacking, and summer is a nap." Only in winter will people be clear-headed, refreshed and not tired. This is the normal physiological and psychological response of the human body to the natural environment. In winter, when the weather is cold, the blood vessels on the surface of the human body contract, and a large amount of blood flows into the brain, thus providing sufficient oxygen and nutrition, and the brain cells are active and will not feel tired. In spring, summer and autumn, due to the rising temperature, the blood vessels on the human body surface dilate, outdoor activities increase, and the blood supply to the brain is relatively reduced, which leads to the decrease of the excitability of brain cells and easy fatigue. Therefore, in the warm season, people should maintain a moderate and relaxed life to prevent fatigue as much as possible.