According to the American Sleep Association,1 up to 70 million Americans have a sleep disorder, nearly 40 percent unintentionally fall asleep during the day at least once a month and nearly 5 percent have nodded off while driving at least once. Insomnia is the most common sleep disorder, with 10 percent of American adults struggling with chronic insomnia and 30 percent reporting occasional or short-term insomnia.

Interestingly, insomniacs will often insist they’ve not slept a wink all night, even though they’ve actually been sleeping. Researchers have now discovered there’s a reason for this discrepancy in experience, and it has to do with consciousness. In a nutshell, even though the brain is sleeping, insomniacs remain consciously aware, and therefore believe they’ve not slept at all.

Many Insomniacs Remain Conscious Even When Asleep, Study Finds

Daniel Kay, a psychology professor at Brigham Young University in Utah who led the study,2 told Medical News Today,3 “… [Y]ou can be consciously aware and your brain [can] be in a sleep pattern. The question is: What role does conscious awareness have in our definition of sleep?” Traditionally, it’s been believed that sleeping involves the absence of conscious awareness, but Kay’s team was able to conclude that this is not categorically true.

To investigate the role of consciousness during sleep, the team analyzed the sleep patterns and subjective experience of 32 people with insomnia and 30 who reported sleeping well.

Once the participants were deemed to be asleep, based on their brain patterns, a radioactive tracer was injected into their arms. Using brain imaging, the researchers were able to examine neurons that remained active during sleep, and their exact locations. The following morning, the participants were asked about their subjective experience of their sleep. Medical News Today explains the results:

“The study found that people with insomnia who reported that they had been awake, even when the polysomnography showed otherwise, had increased activity in brain areas associated with conscious awareness during the dreamless phase of sleep — that is, nonrapid eye movement sleep …

[I]t is normal during the process of falling asleep for the brain to send inhibitory neurons that make people less and less consciously aware until they’ve reached a state of deep sleep. However, what the findings of the new study suggest is that people with insomnia may not feel as though they’re asleep until their brain experiences a greater inhibitory activity in areas that are linked to conscious awareness.”

Normal Sleepers May Not Get as Much Sleep as They Think

As noted by the authors,4 “Brain activity in the right anterior insula, left anterior cingulate cortex, and middle/posterior cingulate cortex may be involved in the perception” of insomnia. People who reported sleeping well turned out to have increased activity in the same areas of the brain as insomniacs. The reason for this is because your brain goes through “an inhibition process” when you fall asleep, gradually lowering your conscious awareness.

While insomniacs require a greater level of inhibition before their consciousness recedes, many good sleepers report falling asleep long before their brainwaves indicate that they’re actually sleeping. This is basically the reverse situation of insomnia: Good sleepers lose conscious awareness at a very low level of inhibition, making them believe they fell asleep much faster than they actually did, based on their brain patterns.