When menopausal hot flashes caused sweat to run down Donna Cook's face during business meetings, she joked to concerned colleagues, "I'm having my personal summer." But for executives like Cook, menopause symptoms such as profuse sweating, nasty mood swings and memory lapses aren't funny. Cook, 54, felt self-conscious when she had to blot up sweat while giving presentations at System Planning Corp., an Arlington, Va., firm that does scientific research and government contract work. She said she would awake several times a night in drenching sweats after she stopped taking hormone replacement medication, which she had been on for about 10 years. "I would oversleep in the morning. I'd miss the alarm. I'd be late for work. I constantly felt like I was playing catch-up," she said. Sometimes, she had trouble remembering how to do routine duties. Two years later, her symptoms are less frequent and severe, but her problem points to the embarrassment and loss of confidence suffered by many women executives at midlife.