Nightmares can be fairly long and complex. The person senses a threat to safety or life. As the threat increases, so does the sense of fear. A person tends to wake up just as the threat or danger reaches its peak.

    About 3 percent of young adults have frequent nightmares. One in two adults has a nightmare on occasion. An estimated 2 to 8 percent of adults are plagued with frequent nightmares. Stress, depression, and anxiety are commonly associated with nightmares in adults. A major life-changing event can cause them, such as loss of a job, financial worries, marital difficulties, death of a spouse, or moving to another house. Alcohol abuse or abrupt withdrawal from alcohol can also lead to nightmares.

    Traumatic experiences such as surgery, brain injury, war, and combat, with their attendant post-traumatic stress disorder (PTSD), can bring on nightmares. Stress is thought to be the most common source of nightmares, so relaxation techniques, such as yoga and meditation, have proven helpful. And eating right beofre going to bed can increase the frequency of nightmares, since eating increases metabolism and brain activities.

Adopted from: Lany Scheckel, Ask a Science Teacher250 Answers to questions You've Always Had about How Everyday Stuff Really Works, New York. Workman Publishing Company, Inc., 2011.

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