After tempering, refined gold is refined into steel, grindability, water-washing quenching, tempering, sharpening, sharpening, late bloomer, sharpening, etc.

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Exercise is a Chinese vocabulary, pronounced duàn liàn, which is defined as physical activity that uses planned, structured and repeated physical activities to improve the health of one or more body parts. Make the body strong through exercise, and cultivate virtues such as courage, wit and safeguarding collective interests.

Modern sports physiology research shows that the highest and lowest points of human physical strength are controlled by the "biological clock" of the human body and generally reach the peak in the evening. For example, the metabolic rate of the human body will peak at 4 pm to 5 pm, and the flexibility and flexibility of the body will reach the best state.

Heart beating and blood pressure regulation are most balanced between 5 pm and 6 pm, while the body's sense of smell, touch and vision are also most sensitive between 5 pm and 7 pm. So, on the whole, the effect of exercise at night is better.

In addition, the hormone activity of the human body is also in a good state between 4 pm and 7 pm, and the body's adaptability and nerve sensitivity are also the best. Therefore, experts advocate evening exercise, but in the evening time, we should pay attention to the intensity of exercise, otherwise too high intensity will excite sympathetic nerves and hinder sleep.

Specific analysis:

In the cold winter, many people choose morning exercises to enhance their immunity. However, isn't outdoor fitness the sooner the better? Relevant health experts suggest that outdoor fitness in winter should be carried out after sunrise.

It is understood that the ground temperature is low before sunrise in winter, and the content of pollutants such as carbon monoxide and carbon dioxide released in the air in the morning is high. In addition, harmful pollutants such as nitrogen oxides, hydrocarbons and lead in automobile exhaust also gather on the ground. If people get up early to exercise, they will inhale a lot of smoke and toxic gases. Long-term exercise in this environment may lead to fatigue, dizziness, pharyngitis and other diseases, which are harmful to the body.