Sleep is crucial to people’s quality of life and health, and it is estimated that a man spends one third of his life to sleep. Without drinking or eating, one could live 7 days; while without sleeping, one can only live 4 days. While sleeping, the nervous system, circulatory system, endocrine system and the nerve reflex of muscles undergo many obvious changes in comparison with those in the daytime. In addition, the immunologic functions are strengthened during sleep, which helps to prevent various diseases.
The regularity of sleep which is easily disturbed by hot weather and mosquitoes in summer matters most to evaluate the quality of sleep. The air-conditioners can lower the temperature, but it brings noise, deduction of anions in oxygen and some other side effects at the same time, which makes it difficult to guarantee the normal and regular sleep. The bad quality of sleep in summer will induce the decline of one’s constitution in autumn and winter and the weakening of the immunologic functions of the body.
Because of the insufficient sleep at night in summer, nap becomes much more important than ever, especially for the elderly. According to the research, nap is beneficial in the aspects of preventing apoplexy, cardio-/cerebrovascular diseases and senescence, and promoting longevity, etc. However, one should also pay attention to some techniques while taking nap. The nap should not last too long; 1 to 2 hours is appropriate. Taking nap after meals will influence the digestive functions, so 10 to 30 minutes after meals is the best time for a nap. The place of taking nap should also be well chosen. Bed is better than sofa, chair and any other place. In addition, one should take nap in a quiet environment in order to guarantee the quality of sleep.