Racial Differences in Heart Rate Variability During Sleep in Women: The Study of Women Across the Nation Sleep StudyHall MH, Middleton K, Thayer JF, Lewis TT, Kline CE, Matthews KA, Kravitz HM, Krafty RT, Buysse DJ Although the number one cause of death for women in the United States is cardiovascular disease, few studies of heart rate variability have specifically analyzed women. Likewise, there has also been a...