Paragraph EightRegular poor sleep can raise the risk of serious medical conditions like obesity, heart attack and diabetes — and can even shorten life expectancy. Adequate exposure to natural daylight is known to be crucial for governing the body’s circadian rhythm - the built-in clock which dictates our sleeping and waking patterns.A key factor to improve one’s sleep and h_____.
【正确答案】：health
【题目解析】：本段讲的是如何改善睡眠以及健康状况。
