A study of diurnal variation in wrinkles on the human face

We recently evaluated diurnal variations in facial skin elasticity and thickness and reported a decrease in skin thickness and an increase in skin elasticity in the afternoon compared with the morning. This phenomenon may be associated with the effect of gravity on dermal fluids. There have been no reports on the diurnal variation in wrinkles on the face, and we now describe such a study. The subjects of this study included 38 healthy Japanese males and females (mean age 34 years). Wrinkles on their foreheads, in the corners of their eyes and in their nasolabial grooves were evaluated. Replicas were obtained and skin thickness and skin elasticity measured in the morning (0830-1000 hours) and in the afternoon (1530-1700 hours) of the same day. Image analysis of the replicas showed significant aggravation of wrinkles in all areas of the face in the afternoon compared with the morning. The results of skin thickness and skin elasticity were in agreement with those of our last study. Swelling tended to occur in the morning due to the effects of gravity during sleep. Therefore, wrinkles may be swollen in the morning. Furthermore, repeated movements of the face due to changes of facial expression may gradually increase wrinkle formation and depth from the morning to the afternoon.