GreetingIt's a common greeting in Japan — genki? More formally "genki desu ka". This is very similar to the English "how are you?". People usually answer with an affirmative "genki!".
Genki and HealthWhich comes first energy or health?
While many Western people would believe that you feel energetic because your healthy. Japanese tend to believe that a strong life force (energy) will make you healthy. This is based on ancient Chinese philosophy and medicine.
The kanji for the word genki (元気) mean "spirit source". This is linked with the Chinese concept of Qi (often translated life force).
Qi is the basis for Chinese medicine — many diseases are thought to be caused by disruptions in your life force. This has translated to Japanese culture in a very generally way. The Japanese tend to believe that by keeping a positive and high energy outlook you can stay healthy. In other words, genki people live longer.