The most suitable temperature for the human body is 25 ℃, but different parts of the human body, different ages, the thickness of clothing, activities and other different, the human body feels comfortable temperature is also different. The temperature in summer is 19-24 ℃ human body is the most comfortable, winter is 17-22 ℃. The more comfortable temperature of different parts of the body, the lower the temperature outside, such as the buttocks need higher temperature than the hands and feet. Women’s comfort temperature is higher than that of men, middle-aged and elderly people’s comfort temperature is higher than that of young people, and the elderly need higher. The body temperature rises during strenuous activity, the body dissipates heat, so the ambient temperature requirements are low, and about the same for mental work and rest. The most suitable temperature for the human body during sleep is 20-22 ℃, higher than 24 ℃ or lower than 18 ℃ sleep will become shallow, not easy to fall asleep.