“We’re supposed to be these crazed people all day and then suddenly become Buddhists at night,” she said. One benefit of the 3 or 4 a.m. wake-up is that it gives women the rare time to actually check items off the list. Some 4:30 a.m. wakers even relish the extra hours, getting up to reorganize the linen closet or returning e-mail.

“I have some pretty creative moments at 3 a.m.,” said Ms. Stoga of Illinois, who works full time as a marketing consultant. “Many times, I just up and start my day.”

Elizabeth Schwartz, 48, a child psychiatrist and mother of four in New York, said her minutes in the wee hours, normally devoted to “worrying and then worrying about the worry,” proved useful when she had to retake her medical boards, which is required every 10 years. “The only time I could study was from 4 to 6 in the morning,” she said.

Ms. McCoy of Oakland said she knew all the “sleep hygiene tricks” but thought she had discovered the key to her wakefulness.

“I’m pretty sure I wake up at 3 because subconsciously, I know I’ll have this time to myself,” she said. “It’s the only time in a 24-hour period when no one needs me or wants me or expects me to do something. Despite the inconvenience, it’s a time that’s blissfully mine.”

Sleep - or not - on that.

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By PAMELA PAUL