There are a few trivial tricks you can use to refresh yourself. The tips are generally useful for long-term or short-term, acute challenges, but if you just want to be more energetic and fit in general, they'll come in handy too.

An interview with Dr. Tamás Sebestyén - Psychologist, lawyer, mediator
How did you first encounter the herb ginseng? As a psychologist, how do you see people and our society? What are the effects of ginseng? How do you see the potentiating effects of ginseng?

Should I drink it instead of coffee? In what form is it available? Can I take more if I am very tired?