Whether you’re obsessed with dream interpretation or are only mildly interested in that dream you keep having about all your teeth falling out, most of us can agree that the subconscious mind is one of the stranger things in life. 

Sometimes you’ll have pleasant dreams and other times you’ll have nonsensical ones. Maybe one night you’ll wake up in a sweat from a realistic and terrifying dream. Then there are periods when you’ll realise you’ve gone a week without remembering any of your dreams if you’re having them at all.  

To figure out why this happens ― and what it might mean about the quality and quantity of sleep we’re getting ― we consulted sleep experts. Here’s what they had to say.

Sleep cycles, sleep quality and morning distractions all play a role in dream recall.

If you’re going through a period where you can’t remember any of your dreams, you may be going through a specific phase with your REM (rapid eye movement) sleep.

Most active dreaming happens during REM sleep, which is about 25% of the night. REM cycles continue to get longer as the night progresses, with the longest period happening in the morning. So if you have an alarm set to a specific time that’s not during one of your REM cycles, that could be the culprit. 

Another possibility? Your technology use. “If you’re immediately distracted when you wake up ― for example, a phone call, or having the radio or news on ― that could wipe out your dreams,” Tore Nielsen, a dream researcher at the University of Montreal, told HuffPost. “Or sometimes the content of your dreams just isn’t that memorable.” 

And if you never remember your dreams ― or if you exclusively have nightmares ― you may need to work on getting higher-quality sleep.

“This could be happening because you are not sleeping enough hours at night,” Nielsen said. “When you curtail your sleep, it is often the long bouts of morning REM sleep that are sacrificed, and that is precisely when we have the longest, most intense and memorable dreams.”

The sleep phase also affects if you remember full dreams or random snippets.

You’ve likely had times you remembered very realistic dreams that seemed like an extension of your everyday life. Other times, maybe you could only recall bits and pieces of a dream.

According to Andrew Varga, a neuroscientist and physician at the Mount Sinai Integrative Sleep Centre, these different types of dreams could be occurring during different phases of sleep.

“It is thought that most plot-based dreaming occurs during REM sleep, irrespective of whether it is bizarre or more realistic,” he said. “For a long time, dreaming was thought not to occur in non-REM sleep, but this has been challenged recently. That said, non-REM dreaming is thought to be less plot-based ― more feelings and scenes.”

And then there’s lucid dreaming, which is when you’re actually aware that you’re dreaming. If you’re a frequent lucid dreamer, it could be indicative of how your brain works.

“Frequent lucid dreamers had increased functional connectivity (increased simultaneous blood flow) to the anterior prefrontal cortex and more posterior temporoparietal association regions of the brain,” Varga said. 

Even if you never remember dreams, you are likely having them.

Varga said the question of whether we always dream, even if we don’t remember those dreams, is a bit of a philosophical question, like “If a tree falls in the forest and there is no one around to hear it, does it make a sound?” But the answer is probably yes.  

“Most active dreaming occurs during REM sleep, and it is fairly uncommon to have no REM sleep at all, although it can happen, for instance, in severe sleep apnea,” Varga said. “So by logical extension, there are probably dreams, even if they are not recalled, but ever proving this can be difficult.”

Niesen agreed that proving that we always dream is difficult, but he also believes that some level of cognitive activity always occurs.

“Sometimes it’s just low-level thinking that often doesn’t involve emotions, vivid images or a storyline,” he said.

Dreaming is complicated ― and there’s still a lot more we need to learn about it to fully understand it, according to experts. So for now, just try to enjoy how strange and sometimes fun the subconscious mind can be.