Bad dreams are the stuff of nightmares

Scientists suggest that repeated episodes can be a risk factor for cardiovascular problems and elevated blood pressure

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Nightmares are more common than many realise. After waking startled, you often forget the disturbed dream quickly. However, we now know more about what is happening to your body. Sleep laboratory studies have revealed your cardiovascular system is getting an intense workout — as your heart rate and blood pressure escalates ~ because your body feels it’s escaping some terrifying ordeal.

Scientists now suggest repeated nightmares could be a risk factor for cardiovascular problems, such as sustained elevated blood pressure when awake. Heart rhythm is more likely to become irregular during stressful sleep, meaning you should pay more attention to nightmares.

The occasional unpleasant encounter while asleep is probably harmless, but if you suffer two or more nightmares a week, it's possible these are symptoms of some kind of underlying psychological disorder.