For some, dreams are easily remembered. Others struggle to grasp on to the scenarios they dreamed up when asleep. Why is it that some people can't remember their dreams once awake? The reasons lie in the way we sleep and the chemicals in our bodies.
When we sleep, our brain goes through four different mental states. The final state, REM or Rapid Eye Movement, is when the brain begins to dream. In REM sleep, the eyes twitch rapidly, the heart rate lowers, and the body enters a paralysed state known as atonia. It's at this stage that the levels of two chemicals in our brains vital to our dreams change.
The production of acetylcholine increases, triggering intense activity in the brain. Acetylcholine controls how vivid our dreams appear to us. Meanwhile, norepinephrine, a chemical which regulates our alertness and stress, decreases. Lower levels of norepinephrine help the brain process dreams stress-free, but also reduce the ability to memorize dreams during sleep.
The levels of these two chemicals spike drastically when we fall asleep quickly or wake up to an alarm, making it harder for the brain to retain dreams. Moreover, sometimes the brain doesn't remember dreams because they are simply not exciting enough.
What can you do if you forget dreams easily but don't want to?
"Dreams are incredibly fragile when we first wake up, and we don't really have an answer for why that is," says Harvard Medical School sleep researcher Robert Stickgold to BBC. "If you're the kind of person who leaps up out of bed and goes about their day, you're not going to remember your dreams. When you sleep in on a Saturday or Sunday morning, that's an excellent time to remember dreams.
There are also other techniques to help you remember dreams better. Watch the video above to find out more.
