‘Researchers at the University of California, San Diego (UCSD) School of Medicine have found that the levels of a pituitary hormone that increases testosterone are enhanced after exposure to bright light in the early morning. The findings suggest that light exposure might serve some of the same functions for which people take testosterone and other androgens.

One of the study’s authors, Daniel Kripke, M.D. UCSD professor of psychiatry, added “the study also supports data that bright light can trigger ovulation in women, which is also controlled by luteinizing hormone (LH), the pituitary hormone we studied.” ‘ I wondered, reading this article (but not the actual scientific research paper) if the effect would persist with chronic rather than short term light exposure and whether, for example, there would be a biological difference between high-latitude and equatorial dwellers in this respect.