This is the 790th most frequent Russian word.
здоровье
Health.
In this sentence, "здоровье" refers to general physical and mental well-being.
Здоровье — это самое важное в жизни.
Health is the most important thing in life.
Here, "здоровье" is used in the context of an individual's personal well-being.
Ему нужно следить за своим здоровьем.
He needs to take care of his health.
In this case, "здоровье" relates to the improvement and maintenance of well-being.