Skin physiological parameters in early bedtime group (S0) and late bedtime group (S1). Significant differences were shown in the figure. (A) Hydration, (B) TEWL, (C) Sebum, (D) Melanin, (E) Hemoglobin, (F) R2, (G) F4 and (H) Wrinkle. *P < 0.05, ***P < 0.001.