Another health sign of bad dreams are related to the heart. A study of more than 6,000 patients in the Netherlands Journal of Medicine found that those patients who had an irregular heartbeat had more than three times the number of nightmares than those who had no heart problems. Those who also had chest pains had them increase sevenfold after nightmares. These two conditions may be related to breathing problems stemming from less oxygen reaching the brain, thereby triggering nightmares.

Migraine headaches may also be related to nightmares. The very painful headaches can strike at any time, but those that arrive at night may be triggered by nightmares, particularly those dreams that feature aggression or anger. It is believed that the migraine's onset changes brain chemistry.

Dreams also may be a sign of lack of sleep. Sleep paralysis may result from insomnia, which about one in 20 people will experience at some time in their lives. The condition, as the name implies, causes the patient to be “paralyzed” and unable to move shortly after waking up. The cause may be something in our brains that controls the muscles as we dream, and the inability to move upon awakening may indicate damage to that location in the brain.

The condition not only paralyzes the patient, but also creates the hallucination that someone is either pressing on their chest or is present in the room, both mere imaginary conditions. Either way, it can be a terrifying experience for those who experience it.

Other Causes for Weird Dreamland Trips

Outside conditions sometimes may play a role in dreaming. Being too hot or too cold may result in a dream that presents those conditions. This can disturb sleep and wake the dreamer. A fluctuation in female hormones is often a cause of temperatures rising during the night, creating dreaming conditions that reflect menstrual cramps, bloating or other conditions associated with menses or even menopause.