German expert Hans Gunter Weiß said naps have many health benefits, as they have a positive effect on the cardiovascular system, help restore vigor and vitality, increase the ability to focus and improve memory performance.
The researcher added in the field of sleep that a nap that is beneficial to health should not exceed 20 to 30 minutes, otherwise it will lead to adverse results, as sleeping longer than that leads to entering the stage known as "REM sleep" ( Rapid eye movement sleep), i.e. dream stage.
Upon awakening after this stage, one suffers from lethargy, moodiness and poor focus, and it takes a long time for him to regain his activity and focus again.
Also, naps - which exceeds 20 minutes - cause difficulties during sleep at night.