http://www.sleeptracker.com/features.html http://www.amazon.com/s.html/ref=bl_sr_hpc?ie=UTF8&node=3760931&brand=Sleeptracker http://techno.e2b.org/note/384/wake-up-naturally-with-bioalarm-clock.html Wake Up Naturally with Bio-Alarm Clock There are a few types of bio-alarm clocks available such as Sleeptracker, SleepSmart and aXbo Sleep Phase Alarm Clock. Sleeptracker can be worn on your wrist like a watch. It will monitor signals from your body that indicate whether you are asleep or awake. SleepSmart is a headband with circuits that detect brainwaves during sleep, and the aXbo Sleep Phase Alarm Clock is a wristband that reads body movements. Bio-alarm clocks are becoming very popular nowadays. Businessmen, travelers, students, etc. find it very useful and helpful. Having said that, there are also scientists who disagree with the use of these scientific products. Dr. Gregory Belenky, a sleep expert at Washington State University Spokane, has commented that light stage sleep isn’t the best time to be woken by an alarm. Dr. Gregory is of the opinion that light sleep stage is the hardest time to wake a person up unnaturally and he also has doubts on the functionality of this device. Waking up has become more sophisticated and complicated than when our mums used to holler from downstairs or when our sister/brother used to come and jump on our beds. :o
正常人的夜间睡眠有4个周期（cycle）。第1、2周期一般是标准的90分钟。第3周期比较复杂（与波浪理论相似），可能包括两次REM（快波睡眠），时间可能是120分钟。第4周期可能是75分钟，但随后还有15分钟整理，加起来也是90分钟。合计时间是6小时30分钟，前面要加上入睡时间，普通人是15分钟左右（幼儿园儿童则平均长达40分钟，新婚夫妻当然也是例外），总共6小时45分钟，这就是作息时间表上应该填的睡眠时间。
長老上尊睡眠經（中阿含經卷第二十） http://blog.sina.com.cn/s/blog_b3e35fc7010165fd.html 卧禅图（性命圭旨亨集第三节） http://blog.sina.com.cn/s/blog_b3e35fc7010164xr.html 晏息之法，当向晦时，耳无闻，目无见，口无言，心无累，鼻息无喘，四肢无动。那一点元神真气相依相恋，如炉中种火相似。久久纯熟，自然神满不思睡，气满不思食，精满不思欲，元炁自聚，真精自凝，胎婴自栖，三尸向灭，九虫自出，所谓睡魔不知从何而去矣。其身自觉安而轻，其心自觉虚而灵，其气自觉和而清，其神自觉圆而明。若此便入长生路，休问道之成不成。 Sleep Management Techniques http://blog.sina.com.cn/s/blog_b3e35fc7010164xy.html Sleeping after third cycle is either due to habit or for psychological satisfaction. But it is a waste of time because it never gives you relaxation instead it drains out gained energy during three cycles and people fell tired even after sleeping more. An Ultradian Rhythm: The Stages and Cycles of Sleep http://blog.sina.com.cn/s/blog_b3e35fc7010165cv.html There are some universal characteristics of sleep as stages 3 and 4 occur only in the first two cycles and REM sleep always increases in duration with each successive cycle.
睡眠是提供可再生和自我修复能力的最好源泉，晚上睡得早早上精神好，半小时午睡可以拯救最黄金的下午和傍晚。美国人不午睡下午只能靠咖啡因提神不健康不可持续，现在是信息化大数据时代，脑力逐渐代替工业化的体力，所以工业化不午睡的习惯让大脑不休息很不科学，脑力和效率大大降低严重浪费下午和傍晚的黄金时间，不午睡又成了落后时代的产物没能与时俱进