I'm looking for watermelon in the traditional market. But I didn't buy a watermelon, because the seller was sleeping soundly. - I remember that there was a book that explained good sleep (I forgot the title of the book). Well ... for those of you who have enough time to take a nap, keep in mind that sleeping for 60 minutes can improve cognitive. You will be easier to think, better memory, even more sharp concentration. - Meanwhile, sleeping in the afternoon for 90 minutes or more, meaning that it has entered in a period of full sleep cycle or REM (Rapid Eye Movement) which will help increase creativity, improve memory emotional and procedural parts and will automatically replace the 'sleep debt' at night day. - But remember not to sleep in the afternoon, with more than 2 hours, because it increases the risk of cardiovascular disease, weakness and disorientation. - According to research, the most natural time to sleep in the afternoon based on the human circadian rhythm is between 2pm and 4pm.