https://www.scientificamerican.com/article/mental-downtime/
the mind obliquely solves tough problems while daydreaming — an experience many people have had while taking a shower. Epiphanies may seem to come out of nowhere, but they are often the product of unconscious mental activity during downtime
Solutions emerge from the subconscious in this way only when the distracting task is relatively simple, such as solving an anagram or engaging in a routine activity that does not necessitate much deliberate concentration, like brushing one’s teeth or washing dishes.
Psychologists have established that vacations have real benefits. Vacations likely revitalize the body and mind by distancing people from job-related stress; by immersing people in new places, cuisines and social circles, which in turn may lead to original ideas and insights; and by giving people the opportunity to get a good night’s sleep and to let their minds drift from one experience to the next, rather than forcing their brains to concentrate on a single task for hours at a time.
In a four-year study, Leslie Perlow of the Harvard Business School and her colleagues tracked the work habits of employees at the Boston Consulting Group. Each year they insisted that employees take regular time off, even when they did not think they should be away from the office. In one experiment each of five consultants on a team took a break from work one day a week. In a second experiment every member of a team scheduled one weekly night of uninterrupted personal time, even though they were accustomed to working from home in the evenings.
After five months employees experimenting with deliberate periodic rest were more satisfied with their jobs, more likely to envision a long-term future at the company, more content with their work — life balance and prouder of their accomplishments.
So what should you do?
get seven to eight hours of sleep every night, to use all their vacation days, take power naps and many small breaks during the day, practice meditation, and tackle the most challenging task first thing in the morning so they can give it their full attention