Schwartz and McCarthy in a paper for Harvard Business Review ("Manage your energy, not your time") argue that the capacity for work can be re-energized with greater and bettter output than by working more hours.
How can we achieve that? According to the authors, our energy comes from body, emotions, mind and spirit. Those forms of energy come from:
Physical energy: comes from nutrition (for example light snacks every three hours), exercise, sleep and rest (regular breaks respecting ultradian cicles every 90 min or 120 min)
Emotional energy: awareness of whar triggers negative emotions, expressing appreciation to others.
Mental energy: fully focusing from 90 to 120 min, establishing priorities for next day.
Spiritual energy: sense of meaning and purpose, establishing a few rituals (gratification, living one's core values).
Re-energizing seems to be hard work but feasible. Our quality of life certainly deserves we dedicate time to it.