The average adult requires 7 to 8 hours of sleep daily. According to the National Sleep Foundation (NSF) 2005 Sleep in America Poll, 40% of the respondents reported <7 hours of sleep on weekdays. The survey also noted that 14% of Americans perform shift work that goes against the body's natural circadian rhythm. Moreover, most diets contain a great deal of caffeine, which remains in the body for an average of 3 to 5 hours but can continue to affect individuals for up to 12 hours.
Another NSF poll found that 36% of the 1000 Americans surveyed reported a current sleep problem, 27% reported occasional insomnia, and 9% reported chronic insomnia. On average, the individuals with occasional insomnia had had difficulty sleeping for 9.3 years, compared with 13 years for individuals with chronic insomnia.Work-related stress was the most frequent reason for insomnia among individuals with occasional insomnia. Family-related stress, however, was the most common cause for individuals with chronic insomnia.
One study linked multiple pregnancies to an increased risk of developing atrial fibrillation later in life, and another investigated the association between premature delivery and cardiovascular disease.
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