Whether or not this is “backed up by science” (as replies have focused on), my own personal long term experiment says that for me this is absolutely the case. A

Whether or not this is “backed up by science” (as replies have focused on), my own personal long term experiment says that for me this is absolutely the case. At a certain lull in the day I can either take some time to relax and feel rejuvenated for the remainder, or I can expect to drag throughout. “Loosen the bolts” is an apt metaphor and exactly how I feel.