Neuroscience Letters [via Yahoo] says that "an extra hour of bright light can lift the levels of a pituitary hormone that enhances testosterone in men" according to a new study. More of the luteinizing hormone (LH) is produced in the pituatry gland. LH increases are related to higher testosterone levels in men and encouraging ovulation in women. "It is theoretically possible," they write, "that light exposure, which increases LH secretion, will alleviate sexual dysfunctions in depressed patients."

If you don't want to wake up earlier, get a special lamp.