As so many people start out making positive changes in their diet, fitness exercises, and lifestyle, but they sometimes neglected their sleep qualities. Some of them only sleep six or so hours a night and call it enough for themselves. Or, they lay awake at night stressing about their career, relationships, or finances, making it nearly impossible to fall asleep. Whatever the case may be for you, if you aren't sleeping enough every evening, it is definitely going to influence on your happiness, more than you may have realized.
Is a good night's sleep better than a pay rise at work?
n. 适合度（生物学术语） n. 健康