CLOCK and diabetes mellitus: In our study, night exercise not only improved impaired CLOCK expression caused by diabetes (p < 0.05) but also decreased CLOCK expression (p < 0.05) compared with morning exercise (Figure 3A,B), indicating that night exercise is better than morning exercise in alleviating impaired CLOCK expression induced by T2DM, which is speculated that night exercise is more consistent with the biorhythm of mice.