Research shows links between dreaming less and worse mental and physical health.
Throughout the night, we pass through four stages of sleep several times. We do the majority of our dreaming during the fourth stage, called the 'rapid-eye movement' (REM) phase.
Research has found that about one in three American adults don’t get enough sleep in general and missing out on dreaming that occurs during REM-sleep can have particularly dire consequences for both our mental and physical health.
A study from the University of Arizona highlighted the wide array of REM-related problems that are forgotten as dreaming-sleep slips through the cracks between sleep science and psychology.
Science has come a long way since Sigmund Freud wrote The Interpretation Of Dreams, in 1899, but we still don’t have a clear answer to the question of why we dream.
The stage of sleep during which we have the most active dream lives, the REM cycle, was once thought to be the most deeply restful phase of sleep.
Now, much contemporary research says that the stage before REM sleep, called deep non-REM sleep is the most restful. But Dr Rubin Naiman, a psychologist specializing in sleep and dreams at the University of Arizona, says that we need both.
He compares much of sleep and dreaming to bodily nourishment. He says that prioritizing deep non-REM sleep over dreaming REM-sleep is like ‘saying which is more important, food or water?’
‘We can actually go without food for weeks and weeks, but without water for only a few days. The brain prioritizes deep sleep over REM sleep, and if someone is sleep deprived they will dive into deep sleep to catch up,’ Dr Naiman says.
‘But in order to be healthy, you need to have both,’ he adds.
Loss of not just sleep, but the REM sleep during which we dream, has been associated with greater risks of inflammation, pain sensitivity, obesity and memory problems, including dementia and Alzheimer’s disease.
The link between REM sleep and Alzheimer’s is quite clear. Studies have shown that those that don’t enter the dreaming phase of sleep as quickly are more likely than others to develop Alzheimer’s.
When sleep is disrupted, a chemical called soluble beta amyloid tends to build up, interfering with cognition and kill brain cells. The presence of the chemical in the brain is one of the earliest warning signs for the onset of Alzheimer’s.
Dr Naiman laments the fact that many of his colleagues dismiss dreams as meaningless, and cites evidence that memory consolidation happens during REM sleep, and that dreams may be a part of this process.
Studies have shown an increase in REM sleep activity in the brain for those who are learning a new language, suggesting the sleep phase’s involvement in declarative memory formation.
‘We have known for years that there is a strong correlation between memory loss and damaged dreaming,’ says Dr Naiman, ‘when we don’t dream well, we don’t remember well.’
REM sleep affects different parts of our anatomy than other stages of sleep do.
‘The brain and viscera are more relaxed in deep sleep,’ says Dr Naiman, ‘but voluntary muscles are actually more relaxed in deep sleep,’ says Dr Naiman.
He also cites a long line of research documenting links between dreamless sleep and depression.
During REM sleep, the brain’s paralimbic system, which is responsible for emotional information processing (among other things) becomes much more active, while suppressing the dorsolateral prefrontal cortex, which is involved in executive functions.
This pattern appears to occur only during REM sleep, when research has shown that the brain is engaged in the process of consolidating negative emotional memories.
‘Dreaming down regulates negative emotion,’ says Dr Naiman. ‘There’s a strong correlation between certain kinds of damaged dreams and depression.’
He says that sleep is comparable to emotional nourishment too.
If, as recent research suggests, ‘the gut acts as a second brain, then the brain is a second gut in dreaming,’ he says.
‘The brain chews, swallows, sifts through, digests and mediates what [experiences] we keep,’ Dr Naiman says.
‘If we don’t dream well, we are no longer digesting experience…it’s like psychological indigestion or constipation, which, for me, is a synonym for clinical depression,’ he says.
Counterintuitively, perhaps, drinking alcohol, smoking marijuana, or taking sleeping pills all disrupt sleep, and particularly dreams.
Dr Naiman says that while a glass of wine with dinner is probably okay, a night cap (or two, or three) after dinner probably aren’t.
He says that this is because ‘the body and brain are always seeking equilibrium.’
Alcohol acts as a depressant, slowing down the brain and the nervous system, like the brakes in a car.
‘When the brain is braking, the body tries to balance things out by releasing adrenaline,’ like pressing the gas pedal, Dr Naiman says.
But once alcohol is processed by the digestive system, ‘that foot comes off the brake pretty quickly, but the other foot stays on the gas.’
This leads to a surge of adrenaline that can pull us out of any sleep, including REM sleep, and disrupt the whole resting process.
He says that data suggests that marijuana may help people fall asleep, but then lead to a similar disruptive rush. Sleeping pills similarly can help to put you to sleep, but, like antidepressants and allergy medications contain compounds that interfere with acetylcholine, which mediates REM sleep.
Dr Naiman says that he and his lab have used ‘effective combinations of exercise, morning light and nutrients with vitamin D’ to help people eliminate alcohol, drugs and even alarm clocks – which he says can shake us from important dreams too early – form their lives, and promote healthy, dreamy sleep.