Japanese researchers recently reported in the online edition of the American journal Cell Reports that “social jet lag” adversely affects the ovulation cycle of animals and is a cause of infertility as they age. Regular living in line with the biological clock may help treat age-related infertility. By “social jet lag”, the report refers to the conflict between modern lifestyles and the body’s natural biological clock. The body’s biological clock is based on the early days of mankind, when the sun rose and the sun set. Nowadays, many people “get up earlier than the chicken”, most of them are in the office with insufficient sunlight during the day, and continue to stay under the light for a long time after nightfall. Due to exposure to natural light for a short period of time, inappropriate time and receive too much light, the body’s biological clock will be disturbed. Researchers at Osaka University and Ritsumeikan University in Japan tried to subject healthy female lab rats to the above “social jet lag” and then observed changes in their ovulatory cycles. It was found that older female rats that repeatedly experienced this “social jet lag” stopped ovulating and became infertile. In contrast, female rats of fertile age did not experience changes in their ovulatory cycles and their reproductive functions remained normal even when they experienced “social jet lag”. Shibu Nakamura, an associate professor at Osaka University who led the study, believes that weakening this sense of “social jet lag” may help improve infertility in older female lab rats. Since the human body has a similar biological clock, this finding may be useful for research into the treatment of female infertility.